3^rd International Conference on Theoretical and Condensed Matter Physics October 19-21, 2017 New York, USA

Biography:

Utpal Chatterjee has completed his PhD from University of Illinois at Chicago in 2007. Afterwards, he has conducted his Postdoctoral studies at Matreials Science Division of Argonne National Laboratory with Director’s fellowship. He has joined University of Virginia in 2012. His research is focused on experimental study of strongly correlated electronic systems. His principal expertise in angle resolved photoemission spectroscopy. His research over past 10 years has produced many high impact publications, which include Nat. Commun, 2015; 6: 6313 DOI: 10.1038/ncomms 7313, Nat. Phys. 10, 357; PNAS 110, 17774; PNAS 108, 9346; Nat. Phys. 6, 99; PRL 96, 107006.

Abstract:

Recently, the studies of incommensurate charge density wave (CDW) phases in various 2H-polytypes of transition metal dichalcogenides (TMDs), e.g., 2H-NbSe2 and 2H-TaSe2, have attracted a lot of attention due to intriguing experimental observations, some of which are reminiscent of the enigmatic pseudogap phase in cuprate high temperature superconductors (HTSCs). We present a comprehensive Angle Resolved Photoemission spectroscopy. ARPES) study on 2H-TaS2, a canonical incommensurate CDW material. Comparing our ARPES data together with arguments based on a tight-binding analysis on 2H-TaS2, with those on related materials like 2H-NbSe2 and 2H-TaSe2, we identify the generic and system-specific characteristics of these systems. We find the following generic features of incommensurate CDW TMDs: (i) opening of CDW energy gap (Δcdw) along part of the underlying Fermi Surface (FS) sheets; (ii) finite Δcdw at temperatures above the CDW transition temperatures and particle-hole asymmetry in Δcdw and a lack of one-to-one correspondence between CDW wave vectors and the FS nesting vectors. We have also observed some system-specific features. For example, in contrast to 2H-NbSe2, where Δcdw is non-zero only at a few “hot spots” on a specific FS sheet, Δcdw in 2H-TaS2 is non-zero along the entirety of multiple FS sheets. Using a tight-binding model, we describe this in terms of the difference in the orbital orientations of their electronic states close to the Fermi level. In short, our strong-coupling model can describe both the generic and the material-specific features of these compounds. Therefore, we argue that the strong electron-phonon coupling, including its orbital and momentum-dependence, is key to the incommensurate CDW instability in TMDs.

Biography:

Yshai Avishai (PhD at Weizmann institute), is a professor of theoretical condensed matter Physics at Ben Gurion University, Beer Sheva Israel. He is a fellow of the American Physical Society, and during 2008-2014 he served as a Divisional Associate Editor for Physical Review Letters. In 2014 he was an Outstanding Referee for APS journals. Professor Avishai served as head of the Physics Department at Ben Gurion University, as head of the Ilse-Katz Center for Nanotechnology, as member of the Judging Committees, for Israel prize in Physics and the Emet prize for exact Sciences. He is the author of 235 papers in high level journals including Physical Review Letters and Nature, and an author of three books in Physics. Professor Avishai occasionally serves as Faculty Member at NYU-Shanghai University, and he is an affiliated professor (2017) of the Yukawa Institute of Theoretical Physics at Kyoto Japan. He visited and worked in numerous institutes around the world, Including Argonne National Laboratories, Lyon, Saclay, Orsay, Heidelberg, Tokyo, Kyoto, Hokkaido and others. Professor Avishai holds also a second degree in Economics and speaks numerous languages including French and Japanese. He is also an amateur Piano player.

Abstract:

The feasibility of manipulating a Fermi gas of cold atoms with spin s>1/2 in a specially designed optical potential enables studying a new kind of topological insulators, described by a two band model where cold fermionic atoms with spin s=3/2 occupy a two dimensional optical lattice where spin orbit coupling is relevant. The pertinent time-reversal invariant Hamiltonian is an 8x8 matrix in [spin]x[particle-hole] spaces, whose spectrum and topological properties are remarkably distinct from those encountered for spin 1/2 fermions. Specifically, on each edge of the 2D sample there are two pairs of oppositely propagating helical states. The two states in each pair move along the same direction, but they are protected against scattering with each other: they have different quantum numbers and different dispersion: (E1 proportional to k and E2 proportional to k^3). Strikingly, the corresponding bulk topological numbers are Z1=2 and Z2=0. Thus, the ubiquitous bulk-edge correspondence is broken here because the group velocity (and hence the conductivity) associated with the second edge state vanishes at k=0.

Biography:

Avik Ghosh is Professor of Electrical and Computer Engineering and Professor of Physics at the University of Virginia. He has over 100 refereed papers and book chapters and 2 upcoming books in the areas of computational nano-electronics and low power devices including 2D materials, molecular electronics, low-power devices, nanomagnetism, photodetectors and nanoscale heat flow. Ghosh did his PhD in physics from the Ohio State University and Postdoctoral Fellowship in Electrical Engineering at Purdue University. He is a Fellow of the Institute of Physics (IOP), senior member of the IEEE, and has received the IBM Faculty Award, the NSF CAREER Award, a best paper award from the Army Research Office, the Charles Brown New Faculty Teaching Award and the UVA's all University Teaching Award. His group's research on observing negative index behavior in graphene was voted by Physics World as one of the top-10 Breakthroughs of 2016.

Abstract:

With the current slow-down of Moore's law and the abolition of the ITRS roadmap, there is a pressing need to explore various materials, architectural and physical solutions for low-power electronics, ranging from spintronics to 2D materials to subthermal switching that beats the fundamental Boltzmann limit. Graphene and other 2D materials have been widely studied because of their photon-like band structure and high mobility. However, their gaplessness compromises their ability to switch under gate bias. I will discuss how using a sequence of gated PN junctions, we can make electron flow in graphene resemble optics-with unconventional equivalents of Snell's law for trajectories, Fresnel equation for transmission, Malus' law for polarization and cut-off modes of a waveguide. These equivalents (negative index, Klein tunneling and Veselago focusing) can be used to filter electrons and engineer a gate-tunable transport gap that allows us to turn off the electron flow abruptly without hurting the mobility of the on current. This novel switching has implications for both digital devices and high speed analog RF applications. Extended to 3D topological insulators, the unconventional switching allows us to filter the spins, amplifying their torque at an injecting ferromagnetic by giving us a gate-tunable giant spin hall angle.

Biography:

Patrick M Vora has received a PhD in Physics from the University of Pennsylvania. Subsequently, he was a Postdoctoral Fellow at the University of Pennsylvania and later at the US Naval Research Laboratory as a part of the National Research Council’s Research Associateship Program. He was named an Assistant Professor at George Mason University in 2014 where he has established a research group that focuses on two-dimensional materials. He has published 22 papers in reputed journals.

Abstract:

The structural polymorphism intrinsic to transition metal dichalcogenides provides exciting opportunities for engineering novel devices. Of special interest are memory technologies that rely upon controlled changes in crystal phase, collectively known as phase change memories (PCMs). MoTe2 is ideal for PCMs as the ground state energy difference between the hexagonal (2H, semiconducting) and monoclinic (1T’, metallic) phases is minimal. This energy difference can be further reduced by substituting W for Mo on the metal sublattice, thus improving PCM performance. Therefore, understanding the properties of Mo1-xWxTe2 alloys across the entire compositional range is vital for the technological application of these versatile materials. We combine Raman spectroscopy with aberration-corrected scanning transmission electron microscopy and x-ray diffraction to explore the MoTe2-WTe2 alloy system. The results of these studies enable the construction of the complete alloy phase diagram, while polarization-resolved Raman measurements provide phonon mode and symmetry assignments for all compositions. Temperature-dependent Raman measurements indicate a transition from 1T’-MoTe2 to a distorted orthorhombic phase (Td) below 250 K and facilitate identification of the harmonic contributions to the optical phonon modes in bulk MoTe2 and Mo1-xWxTe2 alloys. We also identify a Ramanforbidden MoTe2 mode that is activated by compositional disorder and find that the main WTe2 Raman peak is asymmetric for x<1. This asymmetry is well-fit by a phonon confinement model, which allows the determination of the phonon correlation length. Our work is foundational for future studies of MoxW1-xTe2 alloys and provides new insights into the impact of disorders in transition metal dichalcogenides.

Biography:

V P Maslov is a professor of National Research University, Higher School of Economics (School of Applied Mathematics). In 1984, he was elected to Full Membership of the Mathematical section of Russian Academy of Sciences directly, without passing through the Corresponding Member stage. He has published over 600 papers and over 20 monographs. He has introduced a series of important notions of which Maslov-type index theory, Maslov classes, Maslov form, Maslov correction, Maslov WKB method, Maslov cycle, Maslov dequantization are best known.

Abstract:

Quantum mechanics has established a new physical picture of the world, a significant contribution being due to the famous treatise “Theoretical Physics” by Landau and Lifshits. In the “Statistical Physics” volume, they obtained the main equations ofthermodynamics without resorting to the so-called three main principles of thermodynamics, which appear in all thermodynamics textbooks. Bohr’s liquid-drop model of nucleus does not involve attraction interaction of particles and is based on a potential well common for all nucleus elements. Our concept of thermodynamics is based on quantum mechanics and the Earth’s gravitational attraction as an element of a common potential well. We say that a condensate is soft if the gravitational forces push the heavier clusters of the solution to the bottom of the vessel, where they form a thin heavy liquid layer without becoming a hard precipitate. Thus, the critical isochore separates fluids into soft and heavy ones. This approach allows describing the behavior of isotherms in the domain of heavy fluids and determining the weight of heavy clusters for each gas. Our model of thermodynamics shows good agreement with experimental data and explains effects such as negative pressure and liquid–solid phase transition based solely on collisions between molecules and the Earth’s gravitational attraction without using attraction between molecules. N Bohr (1938) noticed the deep relationship between nuclear fission and the partition problem in number theory. The author involves methods of number theory as the third constituent of a new model of thermodynamics. This model does not apply to satellites, where weightlessness occurs.

Biography:

Ceballos Garzón Ricardo has a degree in Physics from the National  Pedagogical University, Physics Specialist from the National University of Colombia, Magister in Geophysics of the Central University of Venezuela, PhD student in Engineering Sciences from the Central University of Venezuela.

Carrillo Guerrero Sergio is a Physicist from the National University of Colombia, M.Sc in Physics from the National University of Colombia, Ph.D in Materials Science from the University of Lille 1.

Abstract:

We carry out the study of a theory based on the properties of transport, with the purpose of obtaining a detailed description of the process of optic absorption in the semiconductors. We have derived expressions that show the relationship between the spectra of absorption and the conductivity of the crystals starting from those properties of transport (conductivity) and of the optic transitions. Such a correlation settled down keeping in mind that the model Tight Binding can be used to show the correlation of the moment matrix elements with the optical matrix elements. The relationship between the conductivity and the infuence of the external field was established, including the importance of the optical constants of the material. When delving into the relationship between the absorption spectrum and the electrical conductivity tensor in the semiconductors it was possible to obtain the description of the optical absorption spectrum in terms of the electric conductivity tensor. Intraband absorption in PbSe QD's is present in a broad wavelength range. Broadband response in near to mid-infrared range can be very relevant for ultra high speed all-optical signal processing (telecom applications). Dominant e_ect from the PbSe core in PbSe/CdSe QD's: electronic structure (bandgap, SP splitting), absorption. CdSe QD's show new high intraband peaks corresponding to hole transitions.

Biography:

Anant Raj received his Undergraduate Degree in Mechanical Engineering from the Indian Institute of Technology, Kanpur in 2010. He received a Master’s degree in Nuclear Engineering from the North Carolina State University, Raleigh in 2013 and continued to pursue a PhD degree under the guidance of Prof Jacob Eapen. During his graduate studies, he was introduced to the fascinating field of materials science and the intricacies of probing materials behavior using statistical mechanics and atomistic simulations. He received his PhD on phonon dynamics and beyond-phonon descriptors for energy transport in materials. He is currently working as a Post-doctoral Research Scholar at the North Carolina State University.

Abstract:

Energy transport in low dimensional systems has been of interest for over 60 years, since the seminal paper by Fermi, Pasta, and Ulam on the vibrational modes of a one-dimensional non-linear string, popularly known as the FPU problem. Several studies have demonstrated that unlike bulk three-dimensional systems, the energy transport in low dimensional systems does not follow Fourier’s law of heat conduction. The thermal conductivity for these systems is ill-defined and is reported to diverge, scaling with the size of the system. Such divergence is also observed in realistic polymer chains as well as in two dimensional materials such as graphene. More recently, this anomalous behavior has been linked to the presence of cross-correlation between different phonon modes arising from collective phonon excitations. To elucidate the relationship between the phonon modes and energy transport more deeply, we analyze the local energy fluctuations of a linear mono-atomic chain and relate them to the phonon modes. We demonstrate theoretically that normal modes of the displacements interfere to produce energy wave packets. We further derive the condition that pairs of phonon modes interfere to produce waves of energy if and only if three-phonon scattering law is satisfied by the trio, even in the absence of phonon-phonon scattering. In general, for nth order in the interaction potential, n displacement normal modes combine to form energy waves if and only if (n+1)th order phonon scattering law is satisfied between them. Further, we show that the frequency and decay of the energy normal modes are directly associated with the collective excitation of phonon modes. Our theoretical findings link the established theory of phonon excitation modes to the normal modes of energy in crystal lattices from statistical-mechanical first principles.

Biography:

Leonardo dos Santos Lima has completed his PhD from Federal University of Minas Gerais, Brazil and Postdoctoral studies from Technische Universität Kaiserslautern, Germany. He has published more than 35 papers in reputed journals.

Abstract:

We use the SU(3) Schwinger's boson theory to study the spin transport properties of two-dimensional anisotropic frustrated Heisenberg model at T=0. We have investigated the behavior of the spin conductivity in diferent frustrated spin systems that presents exchange interactions J1, J2 and J3. We have studied the spin transport in the Bose-Einstein condensation regime where the bosons tz are condensed. Our results show an influence of the quantum phase transition point on the spin conductivity behavior. We also have made a diagrammatic expansion for the green-function and do not have obtained any significative change on the results.

Biography:

Eliade Stefanescu graduated the Faculty of Electronics, Section of Physicist Engineers, in 1970, and obtained a PhD in Theoretical Physics in 1990. As a Scientist from 1976, a Senior Scientist III from 1978, he worked in physics and technology of semiconductor devices, and from 1978, he worked in physics of optoelectronic devices. From 1987, and from 1990 as a Senior Scientist II, he worked in the field of open quantum physics. In the years 1995-2000, he held a course called Dissipative Systems for the master degree. In 1991 he discovered that the penetrability of a potential barrier can be increased by coupling to a dissipative system, and described the decay spectrum of some cold fission modes. As a Senior Scientist I, from 1997 he developed a microscopic theory of open quantum systems, and discovered a physical principle for the heat conversion into usable energy. In 2014, he produced a unitary relativistic quantum theory. He received the Prize of the Romanian Academy for Physics in 1983, Diploma as Ordinary Member of the Academy of Romanian Scientists, Diploma and Golden Plate as Founder of the Academy of Romanian Scientists, and the Prize “Serban Titeica” (2014) for the book “Open Quantum Physics”.

Abstract:

Recently, we conceived a semiconductor structure converting environmental heat into electromagnetic energy and, further, into electric energy: while a current I is injected in the device, a super radiant field is generated by quantum transitions of electrons from the n-zones to the p-zones. We notice that this current enhances the lower states of the ohmic contacts between the n-p super radiant junctions, while the upper states of these contacts are depleted. This makes these contacts become colder, the current I traversing these contacts by thermal excitations of electrons, on the account of the heat absorption from the surrounding zones. This is a complex process based on the quantum dynamics of three coupled physical systems: (1) the active electrons in the quantum wells of the super radiant junctions, (2) the electromagnetic field in the device cavity, and (3) the optical vibrations of the crystal lattice, leading to an approximately 3 times variation of the field propagation velocity, according to the crystal refractive index. The dynamics of these systems includes an important dissipative component due to the couplings to the other electrons and to the mechanical vibrations of the crystal. We describe the dissipative quantum dynamics of the three systems by quantum master equations with explicit microscopic coefficients depending on the physical characteristics of the device. We understand the electron and electromagnetic field dynamics in the framework of a unitary relativistic quantum theory. In this theory, a quantum particle is described by wave packets in the two spaces of the coordinates and momenta, of a form providing the Hamilton equations as group velocities of the two wave packets, which include the Lagrangian instead of the Hamiltonian in the conventional wave functions. Unlike the classical relativistic principle of the light velocity consistency, we consider a relativistic quantum principle of invariance of the time dependent phase of a quantum particle.

Biography:

Manuel S Morales is an independent researcher in the field of fundamental mechanics, i.e., origin physics. He has a BFA in illustration and AS in photography. His notable career as an artist inadvertently led to conducting a twelve year experiment at TemptDestiny.com which revealed that the current methods and theories of science are incomplete. He has applied his findings to particle physics, theoretical physics, experimental physics, and has served as a referee for a number of physics journals.

Abstract:

In a twelve year experiment it has been empirically confirmed, without ambiguity, that there are two mutually exclusive and jointly exhaustive (hidden) variables that give rise to existence. What has been revealed is that the two acts of selection are not effects of cognition. They are origin variables of physical existence. This bold claim can be confirmed by all via a simple thought experiment or empirically validated in real life. The findings show that the two complimentary dichotomies of selection can only come to exist not preexist or be existent. As such, they serve to give rise to effects of existence, i.e., matter and the four fundamental forces of nature. Graph analysis of the findings illustrate the construct of how an act (x) directly pairs with its potential (y) in order to become a direct selection dichotomy (z) and how an act (-x) indirectly pairs with its potential (y) in order to become an indirect selection dichotomy (-z). Together, both dichotomies create an X pattern similar to the X-ray diffraction photograph of the famed DNA image taken by Raymond Gosling in May 1952. The difference between the two observations is that one creates an X pattern while the photograph records the effect of an X pattern which in turn prompts further investigation. DNA is known to carry the genetic code of cells and some viruses. The two acts of selection serve to generate everything that exists. Exploration of how the fundamental laws of selection generate genetic codes hopes to open new fields of research that will bridge physics with genetics.

Biography:

Holger Bech Nielsen is Professor emeritus at the Niels Bohr Institute and reputed for being one of the inventors of string theory, vortex lines line paper with P Olesen, Nielsen-Ninomiya (Foerster) No go theorem for chiral Fermions on the lattice, Forggat-Nielsen mechanism for masses of fermions in the Standard Model, and has been very keen on developing his dream of Random Dynamics, that the laws of nature shall come out automatically almost whatever the fundamental theory is taken to be. He gives many popular talks on high energy physics. Recently, he works on the suggested new law of nature Multiple Point Principle, from which coupling constants get restricted (predicted the Higgs mass). The Humboldt prize visiting DESY and several ca 8month visits to CERN.

Abstract:

It is an old idea of ours (H. B. “Nielsen Dual Models'' section 6 “Catastrophe Theory Program'' Scottish University Summer school 1976?) that a most general material with only translation symmetry, but otherwise no symmetries should generically (in general) have some small regions in quasi momentum space, where you ''see" an approximate Weyl equation behavior. The Weyl equation is the relativistic equation for a (left handed) neutrino. This remark means that one could imagine, that there were behind the Standard Model of High energy physics, a very general crystal model with very little symmetry. Even for the Yang Mill or electrodynamics types fields a similar philosophy is possible. There are though some problems with this solid-state type of model beyond the Standard model, for which we thought have some remedy by means of homolumo gap effects. Now a days, the kind of material on which we speculated is being found and very high conductivity achieved for them.

Biography:

Loris Ferrari is graduated in Physics at the University of Bologna, with highest praise. He was awarded with Guglielmo Marconi prize in 1974. He became Assistant of Analytical Mechanics at University of Ferrara (Italy). He became Associate Professor of Condensed Matter Physics in 1981. Since 1985 he held a number of courses in the field of condensed matter at the Department of Physics of the University of Bologna. His research work was initially concerned with glasses and glass transition. In this period he cooperated with Sir N F Mott and W A Phillips of the University of Cambridge. Then he worked in the field of renormalization group theory and non autonomous quantum systems. At present, he works on ultracold bosonic systems and superfluidity. He has published about 80 papers in reputated scientific reviews.

Abstract:

In a gas of N interacting bosons, Bogoliubov’s first step is dropping all the interaction terms between free bosons with moment ,which leads to the truncated Hamiltonian Hc. Bogoliubov’s second step (Bogoliubov Canonic Approximation) is approssimating Hc with a bi-linear canonic form HBCA in the creation/annihilation operators, which can be diagonalized by the well known Bogoliubov transformations. All this leads to the current notion of quasiphonons, i.e. collective bosonic excitation, with wave-like character (at low k), each carrying a finite moment Here we show what happens when Hc is diagonalized exactly. The resulting eigenstates depend on two discrete indices where numerates the quasiphonons carrying a moment , responsible for transport or dissipation processes. S, in turn, numerates a ladder of vacua , with increasing equispaced energies, formed by boson pairs with opposite moment. Passing from one vacuum to another , results from creation/annihilation of new momentless collective excitations, reminiscent of bosonic cooper pairs, that we call pseudo-bosons. Exact quasiphonons originate from one of the vacua by creating an asymmetry in the number of opposite moment bosons. The well known Bogoliubov quasiphonons (QPs) are shown to coincide with the exact eigenstates , i.e. with the QPs created from the lowest-level vacuum (S=0). All this is discussed, in view of existing or future experimental observations of what we call the hidden side of Bogoliubov collective excitations (CEs), i.e. the
pseudobosons.

Biography:

Eugene Machusky is currently Head of the Dept. of Technical Information Protection Systems, Scientific Director of Special Design Bureau "Storm" in National Technical University of Ukraine "Kyiv Polytechnic Institute" (KPI), Kyiv, Ukraine. He received his MEng (1974), PhD (1979), DSc (1989) from NTUU "KPI". He has been a Research Visitor at the University of North Wales (1983-1984, Bangor, UK), Visiting Professor at Harbin Technological University (2015-2018), China. He has also been an Author and Editor of Radio Engineering Encyclopaedia (Kyiv 1999; Moscow 2002, 2009, 2016), Articles in Great Ukrainian Encyclopedia (2016-2017). His scientific fields of interest includes microwave electronics, underwater acoustics, information security, mathematical linguistics.

Abstract:

For the first time, the Unified Quantum Metric system was analytically developed without any artifacts, such as m, s, kg and without measurements at all. The energy diagrams of Feynman were replaced by calculations of harmonic space-time differentials. The main constants of quantum physics are, in fact, dynamic gradients of normal, half-normal, log-normal and truncated normal distribution of inverse radius of pulsing spiral. The Quantum Physics is the logarithmically compressed two-dimensional image of threedimensional motion of wave fronts. One matrix equation [Gi]=2*PI*[Ri]*(1+[Ai]) where Ai, Ri, Gi are eccentricity, radius, density correspondingly, completely describe the 3D motion of wave fronts. Radii and eccentricities are bonded by the argument of information entropy Sqrt(2*PI*E) of the function of normal distribution Ri = 1+2/100*(E +Ai*(1+Sqrt(2*PI*E/100))). Lower limit of the nuclear rotational radius of pulsing spiral R = Integer{10^8*(C/10^7)^(1/64)/10^8 = 1.05456978 corresponds to upper limit of the harmonic rotational speed. C = (R+4*PI*C/10^18)^64*10^7 = 299792457.86759 (Maxwell unit) and K=E+AS+BS=2.7315999984590452 (upper limit of background temperature, Kelvin unit) link electrodynamics and thermodynamics. The number AS = 0.00729 = 1/100/(1.11111111...)^3=1/100/Sum{[137+(137-100)*N]/10^(3*N+2)} is the Schrodinger quantum binary inverse integral number.The number BS=Sum{602214183/10^(3*N+11)}=0.0060281699999…=0.00602817 (Avogadro quantum decimal integral number) connects binary and decimal calculation systems The thirteen digital sequences are sufficient for estimating all fundamental quantumconstants with practically unlimited accuracy.

The following equations functionally links binary, decimal and natural quantum calculation systems (bit-dit-nat): A1=1/137, A0=(PI*E/100)^2, A4=A0+4*(A1-A0), AH=1/(4^2*PI*E), AL=(1+59*Ln(10)), AF=1000/Inteer{1000*Sqrt(137^2+PI^2)},RC=R+4*PI*C/10^18,RE=R+1/E/10^8, RA=R+1/(E+AS)/10^8, RK=R+1/K/10^8, NB=602214183/(1+4*PI/10^8)/10^8=6.022141073235 (reference number of differential entropy, lower limit of harmonic Avogadro unit), [Ni]=(Sqrt(8*PI*E/(8*PI*E+137^2))/(1+2*[Ai]/1000)-1/2/10^7)/10 (Avogadro energy entropy matrix), [MMi]=12-[Ai]/10 (molar mass entropy matrix), [KBI]=Cos(12-[Ai]/10)-Sin(12-[Ai]/10) (Boltzmann phase entropy matrix), [Vi]=[Ri]^64*10^7 (translation speed entropy matrix), AX=5/Root{X*E^X/(E^X-1)=5}=0.0070261763632109 (lower limit of relative inverse eccentrisity, Wien referenceunit).

Biography:

Mohammed Ä°brahim has completed his PhD at University of Technology (IRAQ) in Material Science on 1996 and he got his MSc degree from University of Glasgow (UK) in Reactor Technology (1985). He has published more than 40 scientific papers in material technology in scientific journals and has been serving as Researcher and Teaching Staff in University Of Technology/Chemical Engineering Department. Currently, he is working as an academic staff in Chemical Engineering Department, Faculty of Engineering, Sulyeman Demirel University-Isparta-Turkey.

Abstract:

In recent years, using nanofluids to increase the heat transfer is gaining much more attention among engineers and researchers. Nanofluids are comprised of a concentration of nanoscale sized particles dispersed in a base fluid. The particles can be composed of any type of material, examples include pure metals, oxides, carbides and carbon nanotubes. The base fluid can be any material from pure water, ionic liquids, oils, to diluted organic compounds such as ethylene glycol and oleic acid. A chance to increase the heat transfer by employing nanofluids have opened the way for a spectrum of promising applications like miniature electronic devices, high power electric devices like transformers and enhanced heat transfer in many other energy conversion systems. Magnetic nanofluids also called as ferrofluids, consists of colloidal mixtures of super paramagnetic nanoparticles suspended in a nonmagnetic carrier fluid, constitute a special class of nanofluids exhibiting both magnetic and fluid properties. In these suspensions, also known as smart or functional fluids all features such as fluid flow, particles movement and heat transfer process can be controlled by applying external magnetic fields. In the present work, we proposed to synthesize water base nanofluids consisting of magnetic Graphene-Fe (Ge-Fe) nanocomposite and to study the fluid thermal conductivity in presence and in absence of magnetic field. Graphene was prepared by exfoliation method and graphene-Fe nanocomposite was prepared by co-precipitation of Fe2O3 (over graphene) from aqueous salt solution in alkaline medium. Synthesis of nanofluid has been done by well dispersed of Ge-Fe in a certain fluid. The results obtained showed that, the disperssion of these nanoparticles in fluid, as a magnetic nanoparticle increased the efficiency of nanofluid (when graphene is used alone) and a significant improvment in thermal conductivity has been obtained by addition of Fe to graphene sheets. When the magnetic field is applied, the magnetic dipole moments of the particles align and the particles came in contact with each other and form chains in the direction of the applied magnetic field. When parallel to the direction of heat flow, the magnetic field causes the effective thermal conductivity in the direction of the magnetic field to increase. Characterization techniques like X-ray diffraction (XRD), Scanning electron microscope (SEM),Transmission electron microscope (TEM),Raman shift spectroscopy were used to investigate the morphology and structure of synthesized nanoparticles, while thermal conductivity of nanofluid at different conditions is measured by thermal conductivity meters and temperature thermocouples readings.

Biography:

Numerical methods for differential equations are one of the notable glories of contemporary science. Coupled with much algorithmic ingenuity, numerical methods are widely applied across science and engineering fields. One of the most important numerical methods is the numerical integration which has been the focus of intense research since its development in 1915 by David Gibb. In this abstract, we present the study of numerical integrator based on Fer expansion in the integration of the time-dependent Schrodinger equation (TDSE) which is a central problem to nuclear magnetic resonance (NMR) in general and solid-state NMR in particular. Numerical simulations of NMR experiments are often required for the development of new techniques and for the extraction of structural and dynamic information from the spectra. The development and design of various pulse sequences and understanding of different NMR experiments are based on the form of effective Hamiltonian or effective propagator that satisfies the TDSE which is difficult to solve unless the Hamiltonian is time independent or commutes with itself at two different times. The evolution operator allows obtaining the density matrix of the spin system that has evolved from the equilibrium density matrix due to the application of RF irradiation. The signal intensity depends on the final density matrix of the spin system. For example, if the numerical model is implemented with the approximate solutions of Fer or Magnus, the results of the simulation will show incorrect or undesirable effects of finite pulses and ring-down mainly when dealing with quadrupolar nuclei (I>1/2). In this study we proposed an efficient numerical integrator based on Fer expansion for solving the TDSE to obtain an effective propagator that continually improves the detected NMR signal. We will also compare the performance of the numerical integrator based on Fer expansion with respect to other Lie-group solvers, namely Magnus and Cayley methods.

Abstract:

Eugene Stephane Mananga is a Faculty Member in the Physics Doctorate Program and in the PhD Program in Chemistry at the Graduate Center of the City University of New York. He is an Assistant Professor of Physics and Nuclear Medicine at BCC of CUNY, and an Adjunct Professor of Applied Physics at New York University. He completed his PhD in Physics from the Graduate Center of the City University of New York, and holds six additional graduate degrees and training from various institutions including Harvard University (HMS), Massachusetts General Hospital (MGH), and City College of New York. He did his Postdoctoral studies in the National High Magnetic Field Laboratory of USA, Harvard Medical School, and Massachusetts General Hospital. Prior to joining Harvard - MGH, he was a Research Engineer in the French Atomic Energy Commission and Alternative Energies. He has published more than 40 peer-review scientific articles including prestigious scientific journals and he has been serving as Editorial Board Member for more than 20 remarkable journals. He currently serves as Editor-in-Chief of the Journal of Imaging Science. His scientific contribution was honored during the 70th anniversary (1946-2016) of the Russian Academic of Sciences.

Biography:

Hafiz Muhammad Asif Javed has completed his PhD from Electronic Materials Research Laboratory, School of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an China. He is an Assistant Professor of Physics at University of Agriculture Faisalabad Pakistan. He has published more than 12 papers in well reputed journals. His current research interests include advanced energy nanomaterials, organic–inorganic hybrid nanomaterials for solar cells, TiO2 nanotubes/nanowires arrays, ZnO nanowires arrays and SnO2 nanotube arrays sensitized with semiconductor quantum dots or organic dyes for photovoltaic and environmental applications.

Abstract:

An efficient photoanode for dye-sensitized solar cells (DSSCs) should have several features, such as high dye uploading, favorable band gaps and good capability in electron transport. Herein, TiO2 nanohexagon arrays (TNHAs) were fabricated by using an electrochemical anodization process. Then, the TNHAs were attached onto FTO glass for front-side illumination mode operation. The as-prepared TiO2 nanohexagon arrays had a length of 27.25 μm and an average diameter of 125 nm. SnO2 is a promising wide band gap material for DSSCs due to its high electron mobility. To improve the performance of DSSCs, SnO2 was introduced into the TNHAs by using a one-step facile immersion approach in 0.25 M K2SnO3 solution for 30 min. The as-fabricated SnO2/TiO2 nanohexagon array heterojunction was utilized as the photoanode for DSSCs. The SnO2 nanoparticles had a superior light harvesting capability owe to the higher surface area for dye uploading and the high electron mobility. The SnO2/TNHAs heterojunction based DSSC had a power conversion efficiency of 6.34%, which was 1.32 times higher than that of the pure TiO2 nanohexagon arrays. Furthermore, incident photon-to-current conversion efficiency (IPCE) and the amount of dye adsorption (Ada) are also improved, with values of 63.96% and 6.8×10-5 mol cm-2, respectively.

Biography:

Sergey V Kravchenko has completed his PhD in 1988 from Institute of Solid State Physics, Russia. Since 1998, he is a Professor of Physics at Northeastern University, Boston, USA. His discovery of the metallic state in 2D was listed among 50 main discoveries of the last century in the field of mesoscopic physics.

Abstract:

In two-dimensional (2D) electron system, electrons can move in two dimensions but are confined in the third, pretty much like billiard balls. Low-disorder 2D electron systems are currently the focus of a great deal of attention, particularly for low electron densities, where the interactions between them dominate their behavior, theoretical methods are still poorly developed, and new experimental results are of great interest. Consistent with Fermi liquid theory at high electron densities, these 2D systems are expected to freeze into a Wigner crystal in the dilute, strongly-interacting limit. In the intermediate regime, where interactions are not yet strong enough to cause crystallization, the electrons behave like a strongly-correlated liquid. Our recent data show that the low-temperature (fractions of 1 kelvin) properties of this strongly correlated electron liquid are unusual and very interesting. For example, the spin susceptibility grows and seemingly diverges as the electrons become more dilute, which indicates transition to a new state of matter (Wigner crystal or a precursor). Moreover, I will report the observation of strongly nonlinear voltage-current characteristics that display two distinct thresholds and a dramatic increase in noise at the breakdown of the insulating state. With the roles of voltage and current interchanged, this behavior is strikingly like that observed for the depinning of the vortex lattice in Type-II superconductors. Adapting the model used for vortexes to the case of an electron solid yields good agreement with our experimental results. This strongly favors the formation of the electron solid in the insulating phase as the double threshold behavior cannot be described within existing alternative models.

Biography:

Gennadiy Filippov has his expertise in particle-solid interaction physics. He has completed his PhD from Tomsk State University (Russia). He is the Head of the Laboratory of Biophysics and Bio-Nanotechnology in the Chuvash State Agricultural Academy and Professor in the Chuvash State Pedagogical University in Cheboksary, Russian Federation.

Abstract:

Calculation and further analysis of density matrix (DM) for projectile which collides with a solid film reveals some new representations which hard to be anticipated without the calculation. Namely: 1) The coherence properties in the projectile’s wave field are describing through the special function of coherence. 2) The collision with the solid leads to a significant decrease in the total coherence length of the projectile’s wave field. The coherence length can become much smaller than the initial size of a wave packet of a particle passing through the film. 3) During the collision with solid, the number of different spatial areas where the mutual coherence in the projectile’s wave field is supported, can be multiplied. 4) Every part of projectile’s wave field can be individualizing as the separate particle having own property in its inner quantum state. 5) The procedure which has a responsibility for such a transformation can be characterized as a spontaneous breaking of symmetry. The process described in the point three can be considered as a special form of breaking in quantum mechanics. 6) Knowing the wave packet evolution during the passage through the solid film allows one to explain experimental results on the pore formation during the passage of high charged atomic ions through the thin carbon nano-membranes. 7) The parts of the wave field considered above can be stabilized in its quantum state after been captured in its own polarization well.

Biography:

Ming B Yu has graduated from Jilin University, 1961. Before retiring, he worked as a Lecturer in Zhengzhou Coal Manage College, China, and a Visiting Adjunct Lecturer in University of Georgia, USA. Currently he is still active in studies in theoretical condensed matter physics and nonequilibrium statistical theory of closed and open systems.

Abstract:

It has a long history to study monatomic and diatomic chains with or without impurity as models for dynamics of lattices. By means of recurrence relations method, a diatomic chain with an impurity is studied. The Laplace transform of the momentum autocorrelation function of the impurity is derived. It has two pairs of resonant pole and three separated branch cuts. The poles lead to cosine function(s) and the cuts result in acoustic and optical branches. A frequency theorem is derived governing the upper and lower frequencies of the two branches; Criteria for resonant poles are established; general expres-sions for frequency and amplitude of cosine(s) are derived. The acoustic and optical branches can be expressed as inverse Laplace trans-forms which are not easy to be carried out in general. By means of convolu-tion theorem, analytical expressions for acoustic and optical branches are derived as expansions of even-order Bessel functions. The expansion coeffi-cients of the acoustic branch are integrals of real Jacobin elliptic functions. However, coefficients of the optical branch are integrals of complex elliptical functions. By addition theorem, the expansion coefficients for the optical branch are obtained as integrals of elliptic function along a contour parallel to the imaginary axis in a complex plane. A modulus theorem is derived relating the modulus of elliptic functions in the acoustic and optical branches.

Biography:

Rikio Konno has completed his PhD at the age of 28 years from University of Tokyo and postdoctoral studies from Tsukuba University. He is the Science Section Head of Kindai University Technical College, a famous college based on Kindai University in Japan. He has published more than 25 papers in reputed journals. He won the International Plato Award for the Educational Achievement, the Order of International Fellowship Golden Peace Prize, and Ultimate Achiever Award for Science-Certificate in 2009. He is a member of Physical Society Japan, a Life member of American Physical Society, and a member of Institute of Physics, U.K.

Abstract:

We have investigated the thermal expansion of localized paramagnets, with almost negligible wave-vector dependence of their dumping constant of spin fluctuations. By assuming the Lorentzian form of the dynamical susceptibility, we have found that the thermal expansion coefficient has the T-linear dependence at low temperatures. The volume dependence of the spectral width of spin fluctuations is included accoding to the theory of magneto-volume effects by Takahashi. This dependence is equivalent to that of the specific heat, and both of their T-linear coefficients are related with the magnetic Gruneisen parameters. Our localized paramagnon model will be well applicable to almost localized 5f electron system, UPt3.

Biography:

Luxmi Rani has completed her PhD (Theoretical condensed matter physics: Superconductivity) from IIT Roorkee India in 2015 and received degree in 2016. She has worked as a Post-Doctoral Fellow in Theoretical Physics Division, Physical Research Laboratory Ahmedabad during 2015-2017. She has published over eight research papers in peer reviewed journals.

Abstract:

The discovery of high -Tc superconductivity in cuprates by Bednorz and Müller and the recent finding of the high -Tc iron based superconductors by Kamihara group in 2008 changed the traditional concept and clearly indicated that BCS theory based on the electron-phonon interaction may not be able to explain such high Tc’s and spin fluctuation since antiferromagnetic background can also contribute to the pairing mechanism, and still a debatable issue from the theoretical point of view. The isotope effect coefficients show a deviation (above and below the BCS limit) in Fe based high-Tc superconductors and need careful attention in any theoretical analysis. Motivated from the fact, the present work is devoted to a theoretical analysis of isotope effect coefficient as a function of transition temperature in two orbital per site model hamiltonian in Fe based superconducting system. The expression of isotope effect coefficient has been computed numerically and self-consistently by employing green’s function technique within the BCS- mean-field approximation. It is observed that the isotope effect coefficient increases with the increase of the hybridization while with the increase in coulomb interaction it starts decreasing. On increasing the carrier density per site in two orbital per site iron pnictide system, isotope effect coefficient (α) exhibits large values (much higher than BCS limit) at lower temperatures, while in the under doped case, isotope effect coefficient shows minimum value in superconducting states of the iron based systems. Furthermore, it has been found that the large value of the isotope effect coefficient is the indication of the fact that the contribution of phonon alone is inadequate as the origin of superconductivity in these systems. Finally, the obtained theoretical results have been compared with experimental and existing theoretical observations in iron based superconductors.

Biography:

Rita John is Professor and Head, Department of Theoretical Physics, University of Madras, Chennai, India. She is fulbright Visiting Professor at the Department of Physics and Astronomy, Texas Christian University, Fort Worth, Texas, USA (2014). She has been teaching condensed matter physics for graduate students over 18 years. The book, ‘Solid State Physics’ authored by her and published by Tata McGraw Hill publisher (2014) is used globally by graduate students. She guides PhD, MPhil, MSc and MTech projects. She has over 50 international publications. She is the recipient of various awards and prizes for her academic and research contributions.

Abstract:

Shape memory alloys are intermetallic compounds that have the ability to recover their original shape upon appropriate thermomechanical loading. TiPd, a prominent high temperature shape memory alloy (HTSMA) undergoes martensitic transformation (MT) from the parent B2 (cubic) phase to the product B19 (orthorhombic) phase. We have studied the effect of addition of X (Co, Rh, Ir) on the structural and electronic properties of TiPd shape memory alloys. The site preference of ternary additions X are determined from the calculated formation energy. It was found that X has strong preference for Ti sublattice for the composition considered. The cubic structure of B2 phase is maintained for the substitutional alloying of 6.25% of Ti/Pd sites with X. The density of states (total, site and angular momentum decomposed) are plotted for both Ti43.75Pd50X6.25 and Ti50Pd43.75X6.25 series. Higher stability of Ti43.75Pd50X6.25 is due to the decrease of d states of Ti and X at fermi level with increasing atomic number of X impurities. Though localization effect is more pronounced in Ti50Pd43.75X6.25 series with increasing atomic number of X, the number of d states of Ti remains same. It is Tid states at fermi level that determines the phase stability of these alloys. Also, we have investigated the impact of addition of varying concentration of magnetic impurity Co (6.25, 12.5, 25%) on B2 and B19 phases of TiPd. Band Jahn Teller broadening is observed in Ti25Pd50Co25 which is one of the accompanying features of MT. Band structure calculations are consistent with the results of density of states. Hole and electron pockets observed in the band structure are endorsed in fermi surfaces. Charge density contours are plotted which give an idea about electron charge distribution and nature of bonding.

Biography:

Valentiyn A Nastasenko, the Kherson State Maritime Academy Ukraine, faculties Electrical engineering and electronics, the department of transport technologies. Sphere of scientific interests includes quantum physics, the theory of gravitation, fundamentals of the material world and the birth of the Universe, the author of 50 scientific works in these spheres.

Abstract:

Currently gravitational constant G is defined up to 5 characters, that is 2 or 3 orders of magnitude less than the accuracy of other fundamental physical constants – the speed c of light in vacuum and Planck’s constant h. However in the Earth conditions the possibility of increasing the accuracy of defining G experimentally has reached its technical limit, which requires the search of new fundamental approaches. For this purpose the original approach is suggested and the system of calculated dependences resulted from fundamental physical constants c, G, h, as well as from Planck’s values of length l_p, time t_p and mass m_p, is obtained allowing to refine the presently known value of the gravitational constant G by 3 orders. Scientific discoveries are put of the solution this problem:

1) The possibility of expressing the fundamental physical constants in the framework of their dimension in terms of their Planck’s values l_p, t_p, m_p [1] found in which for the gravitational constant G amounts to (1) [2]:

2) Next transformed constant G of this basis

3) this allowed on a strict basis to determine the wave parameters of the gravitational field:

4) 1-th work hypnotize of this: paper ν_p – is quantum parameter of time 1 second [3] and can be expressed by an exact number of ν_p =7.4∙10⁴²(s^-1)Of this basis gravitational constant, at the strict physical (3) and mathematical level, amounts the value with the accuracy of up to 9 characters (4) [4]:

Taking into account the obtained wave characteristics [5] it can be strictly maintained that gravitational field can only by unified with electromagnetic field having the same wave characteristics. Thus, It can be summed up that unification of given fields is possible only on Plank’s level. This conclusion is confirmed number physical and mathematical level [5].

Biography:

Yoshihito Kuno is Postdoctoral Fellow of Japan Society for the Promotion of Science (JSPS), and a Member of Quantum Optics Group of Kyoto University, Japan. He got his PhD at Nagoya Institute of Technology.

Abstract:

Recently atomic quantum simulation for high-energy physics comes to become an active field in cold-atom physics society. In particular there are a plethora of proposals to build up a quantum simulator for lattice gauge theory by using cold atoms in an optical lattice. To realize the quantum simulator for lattice gauge theory, theoretical proposal for future experiment is important. In this talk, we show theoretically an atomic quantum simulator of U lattice gauge-Higgs model based on an extended Bose-Hubbard model in one dimensional (1D) optical lattice. This quantum simulator of the lattice gauge theory is directly connected towards the Bose-Hubbard model with nearest-neighbor (NN) interactions. In the 1D system the most important ingredient, i.e., Gauss’ law can be implemented in a much simple way, i.e., only controlling the NN interactions. Furthermore we show a global phase diagram. Also by using the correspondence between the Bose Hubbard model and the lattice gauge theory we interpret these phases from the view of the lattice gauge theory. In addition, it is important and interesting to detect the non-equilibrium properties of the quantum simulator. We focus on simulating the dynamics of an electric flux (confinement string) in both Higgs and confinement phase. To study this subject we use the Gross-Pitaevskii equation for the Higgs (superfluid) regime and the semi-truncated Wigner method for shallow confinement regime. We certify that the electric flux spontaneously breaks in the Higgs phase on the other hand in the shallow confinement regime the electric flux is dynamically stable. These results are expected to be measured in future real experiments. Moreover our numerical simulations find that the Schwinger-like mechanism which can be observed. Electric fields oscillate via a Higgs and anti-Higgs pair creation.

Biography:

Azher M Siddiqui is an Associate Professor in the Department of Physics, Faculty of Natural Sciences, Jamia Millia Islamia (Central University), India. He has completed his PhD at School of Physics, University of Hyderabad, India, under the supervision of Professor Anand P Pathak. He has worked as a Research Associate with Dr. D K Avasthi in the Materials Science Group at the Inter University Accelerator Centre (IUAC) (formerly known as: Nuclear Science Centre, NSC,), New Delhi, India. He has over 50 papers to his account in International Journals of repute. He has Supervised two students so far for their PhD and 5 students are currently registered with him to carry out their PhD. He has presented his papers in about 20 conferences and has also taken up 3 major research projects from various sponsoring agencies like UGC and IUAC.

Abstract:

In this work, we report the effects of 100 MeV Ag9+ and O7+ ions irradiation on the structural, optical and gas sensing properties of thermally oxidized thin films of tin and indium. XRD, SEM and RBS techniques have been employed to study the structural, modifications induced in the films because of irradiation. It was observed that, irradiation with 100 MeV Ag9+ and O7+ ions resulted in a decrease in the crystallinity of the films along with a decrease in the grain size due to increase in the lattice strain. The structural modifications induced have been correlated with the simulations based on the thermal spike model. The optical properties of the pristine and SHI irradiated films was examined using UV-Vis spectroscopy. It was noticed that the optical band gap of the films increased upon irradiation with 100 MeV Ag9+ and O7+ ions. The changes in the response characteristics of indium oxide and tin oxide films towards methane and hydrogen respectively due to SHI irradiation are extensively discussed.

Biography:

Georges Bouzerar is a Research Director at Centre National de la Recherche Scientifique (CNRS). He is an expert in quantum and classical magnetism (itinerant and localized) and in quantum transport. He has completed his PhD in mesoscopic physics (interplay between electron-electron interaction and disorder) in 1996 from Paris XI (Orsay) University. He has spent several years as a Postdoc in Germany (Koeln University, Berlin University, Max Planck Institute) and in France (Laue Langevin Institute in Grenoble). He got a Senior Scientist permanent position at CNRS in 2004 and became research director in 2011. Over the past 10 years he has focused attention on spintronics, in particular on magnetism and transport in diluted magnetic semiconductors and non-magnetic impurity induced ferromagnetism. He has contributed by about 25-30 papers to this research area and received a prize in 2014 from the French Academy of Science for his achievements in this field.

Abstract:

The nature of carrier-induced ferromagnetism in both Mn doped III-V compounds GaAs and InP is investigated. Although, direct band gap and effective masses are very close in both InP and GaAs, we demonstrate that the magnetic properties change drastically. The influence of the acceptor level position on magnetic properties will prove to be crucial. Because of both dilution effects (percolation) and short-range nature of the carrier induced Mn-Mn magnetic couplings (calculated), thermal/transverse spin fluctuations and disorder effects (localization) have to be properly treated (beyond effective medium or perturbation approach). To tackle efficiently this issue, different large-scale theoretical approaches are combined: Kernel Polynomial Method (KPM) for the accurate calculation of Mn-Mn couplings, Monte Carlo (MC) and Local Random Phase approximation (L-RPA) for the magnetic properties (TC, T- dependent magnetization, and magnetic excitation spectrum and spin stiffness). TC in (In, Mn)P is found much smaller than that of Mn doped GaAs and scales linearly with Mn concentration in contrast to the square root behavior found in (Ga, Mn)As. Moreover, we find that the magnetization behave almost linearly with the temperature in contrast to the standard mean field Brillouin shape. These findings are in quantitative agreement with the experimental data and reveal that magnetic and transport properties are extremely sensitive to the position of the Mn acceptor level. We finally discuss the transport properties in both compounds and demonstrate that our non-perturbative theory is able to capture not only qualitatively but quantitatively as well the transport properties in these materials such as the Infrared optical conductivity, the carrier and Mn concentration dependent Drude weight, the effects of sample annealing, and also the Metal-Insulator-Transition as observed experimentally in Mn doped GaAs, whilst (In,Mn)P remains an insulating compound.

Biography:

Juan-Luis Domenech-Garret is currently an Associate Professor (Permanent Staff) at the Technical University of Madrid. He is a Member of the Spanish Royal Society of Physics. He obtained his European-PhD from Valencia University (Spain) and CERN (Geneva-Switzerland) with a CERN-PhD thesis. He is a Member of the Plasma Laboratory of the Aeronautics and Space School–Technical University of Madrid. In previous years, he achieved academic positions in: Avila C University–Spain (Lecturer and Associate Professor), Lleida University–Spain (Lecturer and Associate Professor), and Technical University of Madrid (Lecturer).

Abstract:

This talk is focused on the discussion about the role of the generalized Fermi–Dirac Kappa Distribution which describes the electron population in pure metals. First, we present some experimental evidences and phenomenological facts – in such metals the Kappa parameter, which governs the distribution function, appears to vary linearly with the temperature. Taking this relationship into account, we reviewed the derivation of the generalized electrical conductivity. The relationship between the melting point of several pure metals and a material-dependent coefficient which can be obtained by analyzing the material’s thermionic emission is shown. Also, we presented the transport coefficients for non-equilibrium hot metals, i.e., a new generalized thermal conductivity and a generalized Wiedemann-Franz Law, which are compared with experimental results. As a new property, these transport coefficients droped when the metals achieved the solid–liquid phase transition. In addition, we also showed the impact of the temperaturedependent Kappa parameter on the thermionic emission law in metals. Moreover, we compared the Kappa distribution with the wellknown expanded non-equilibrium function. This study leads to an analytical form of the Kappa parameter. The obtained expression shows the connection between the Kappa parameter and the factors causing the departure from equilibrium. We analyzed the behavior of this obtained equation and compared with the experimental one.

Biography:

Jose Alberto Perez Benitez has completed his PhD at the age of 33 years from University of Oriente in Cuba and postdoctoral studies from University of Sao Paulo and University of Aveiro. He is professor of postgraduation of Electronic Engineering at the Instituto Politécnico Nacional in Mexico. He has published more than 30 papers in reputed journals in the area of electromagnetic nondestructive methods and machine learning.

Abstract:

The Magnetic Barkhausen Noise (MBN) results from the discontinuous motion of magnetic domain walls in magnetic materials under the effect of a variable magnetic field. The MBN signal contains information of several materials features. It has been shown that the MBN is sensible to changes in steel properties such as grain size, carbon content and plastic deformation. Also, the MBN allows detecting the presence of applied or residual stress. Recently, was demonstrated that the MBN signal also contains information about the magnetos-crystalline anisotropy energy of the material. This fact represents an important step in the consolidation of the MBN as a method for magnetic material characterization. The study of the correlation between the MBN and the magneto-crystalline anisotropy energy was possible due to the analysis of the MBN signal by time-bands (or applied field-bands). The time-band method also allows indentifying the presence of magnetization stages using the MBN raw signal. However, although the MBN presents a high potential as a method for extracting different material characteristics, it is worth noting that some of these features vary simultaneously, which make difficult to establish correlations between a specific feature of the material and the MBN parameters. In order to solve this problem several approaches have been proposed, most of them concerning the use of pattern recognition and artificial intelligence algorithms. In particular, it have been demonstrated that it is possible to separated the influence of carbon content and plastic deformation on MBN signal using Feature Extraction algorithms and Self-Organizing Maps artificial networks. These algorithms have proven to be successful for separating the influence of two simultaneously varying materials properties on MBN. Additionally, to the aforementioned progress, the comprehension of how to obtain material features using MBN have been also improved, recently, with new models for the simulation of domain wall dynamics using an assembly of micro-mesoscopic model and Maxwell equation solved using Finite Difference method and computed using parallel programming methods.

Biography:

Yuko Ichiyanagi has completed her PhD from Yokohama National University, Japan. She is the Associate Professor of Yokoham National University since 2009. She has published more than 30 papers in reputed journals and has been serving as an International Advisory Committee Member of some reputed conferences.

Abstract:

Mn-Zn ferrite nanoparticles (NPs) and Co ion doped pluralistic ferrite NPs encapsulated with amorphous SiO2 ranging several nm were prepared by our original wet chemical method. MNPs prepared by this method, Si ions are located on the surface, and this characteristic structure enables amino-silane coupling and functionalization is made easier. We have established the way of functionalization of these magnetic nanoparticles in order to conjugate other molecules. We have confirmed that our particles were introduced into the living cells, and these particles were localized by the external magnetic field. Then cancer cell selective NPs were further developed by attaching folic acid. Characterization of obtained ferrite NPs were performed by X-ray diffraction measurements, chemical analysis. Local structure of magnetic cluster was analyzed by X-ray absorption fine structure (XAFS). DC and AC magnetization measurements were performed using SQUID magnetometer. Composition and particle size were optimized for Mn-Zn ferrite nanoparticles. Samples were examined for heating agent from the result of frequency dependence and particle size dependence of imaginary part of AC magnetic susceptibilities χ”. In order to estimate heating effect of magnetic nanoparticles for an application of hyperthermia treatment, increase in temperature of the samples in AC field was observed. Increase rate of temperature was found to be high enough to suppress cancer cells. Finally, in vitro experiment for hyperthermia treatment was carried out for the cultured cancer cells using our pluralistic ferrite samples. Human prostate cancer cells and human breast cancer cells were cultured in a dish and were exposed to an AC magnetic field. As the result, an extensive hyperthermia effect was observed. Using these NPs, MR relaxation curves were investigated. It was found that super paramagnetic behavior and smaller particles were effective for MRI contrast.

Biography:

Feroz A Khan has completed his PhD degree from the Bangladesh University of Engineering and Technology (BUET) and his Postdoctoral research at the University of Delaware, USA, University of Uppsala, Sweden, and the University of Tsukuba, Japan. He is a Professor in Physics at the Bangladesh University of Engineering and Technology (BUET). He is a Leader of a research group called Dhaka Materials Science Group under scientific research collaboration with the International Science Programs (ISP), Uppsala University, Sweden. He has supervised more than 25 Postgraduate degrees that includes Masters, MPhil, and PhD degrees. He has to his credit more than 50 research publications. He is involved in promoting the basic science research through establishment of regional research collaborations with the south-east Asian Universities under the umbrella of International Science Programs.

Abstract:

The structural, magnetic and electrical properties of Mn doped cobalt ferrites Co1-xMnxFe2O4 have been investigated. The samples are found to be of spiel structure. The DC and AC magnetic properties have been measured at different temperatures. A significant change in the electrical and magnetic properties has been observed with increasing Mn content in the sample. It is observed that the ferri-ferromagnetic Curie temperature is tunable by changing the Mn content in the sample. The optimum point is yet to be determined as the research work is in progress. However primary investigation shows that for transition from ferri-to-ferro and ferrito-para the bifurcation point shifts towards the low temperature side. The ac electrical properties have also shown strong frequency dependence. The variation of real part of the dielectric constant ε’ with frequency at room temperature for all samples of composition Co0.75Mn0.25Fe2O4(CMF2),Co1Mn0.25Fe1.750O4(CFM2), Co1.25Mn0.25Fe1.75O4 (CMFZ2), CoFe2O4 (parent) and also of a bi-layer sample CMF-2+CFM-2. It is observed that the dielectric constants of all the investigated samples have gone through a maximum at two different frequency bands 1 MHz- 4.5 MHz and 7.5 MHz.-10.5 MHz. This is attributed to the electronic, ionic, dipolar and interfacial polarizations that occur at the tetrahedral and octahedral sites.

Biography:

Elie A Moujaes has done BA in Physics from the Lebanese University in 1999, MSc in Theoretical Physics from the American University of Beirut in 2003 and PhD in Theoretical Condensed Matter Physics from Nottingham University (2007). At the end of 2009, he has moved to Brazil where he worked on several projects in graphene, including calculations of electronic structure of grain boundaries and molecular dynamics of carbon nanotubes with polymers in the groups of Marcos A Pimenta and Ricardo W Nunes from the Federal University of Minas Gerais (UFMG), in Belo Horizonte, Brazil. He is currently an Adjoint Professor at the Department of Physics/UNIR- Brazil. My general research areas involve electron-phonon interactions, electronic structure calculations of two-dimensional materials, and phase transitions in magnetism.

Abstract:

Transition metal (TM) multilayers, such as those involving Fe and Ni, hold great expectations underpinning the next generation of magneto-electronic devices. Previously, we used a combination of effective field theory (EFT) and mean field theory (MFT) to calculate single site spin correlations in multiple layered disordered Fe1-cNic nanojunctions with Co leads, c being the concentration of Ni in the Fe-Ni alloy. In this work, calculations are presented for the spin wave scattering and ballistic transport for ferromagnetic iron-nickel nanojunctions between Co leads with Ni concentrations c =0.5 and 0.81. The [Fe1-cNic]n alloys themselves are randomly disordered forming n hcp lattice planes between hcp planes of Co leads. To study the spin dynamics for 1≤ n≤ 7, the sublattice magnetizations were previously evaluated on each layer with the help of a virtual crystal approximation (VCA) particularly valid at the length scale of the nanojunctions at submicroscopic spin wave (SW) wavelengths. Localized and propagating magnon modes in the nanojunction are examined within the phase field matching technique (PFMT). These magnonic modes propagate in the symmetry plane of the nanojunction with spin precession amplitudes decaying or matching the SW states of the semi-infinite Co leads. Eigenvectors corresponding to such amplitudes and illustrating some of the cases encountered are given. This same approach is used, together with the Landauer-Büttiker formalism to determine the reflectance and transmittance for the SW incident from the Co leads onto the multilayered nanojunctions. Our results show Fabry-Perot type resonance assisted maxima for the SW transmission spectra of all layered nanojunctions and for both values of the Ni concentration, due to the interactions between the incident modes coming from the Co leads and the nanojunction magnon modes. As the Ni concentration is changed and the thickness of the nanojunction increases, by adding more layers, the positions of such maxima are modified.

Biography:

I Chávez, MS, is a PhD candidate in the Material Sciences and Engineering Research Program at National Autonomous University of Mexico (UNAM). He is assistant professor in the School of Sciences at UNAM. He won 3rd place in the 1st National Journalism Contest 2010, CONACyT, in Mexico with the paper entitled “Noninteger dimensions.”

Abstract:

Applying the generalized Bose-Einstein conden-sation (GBEC)1 theory we extend the BCS-Bose crossover theory by explicitly including hole Cooper pairs (2hCPs). GBEC hinges on three separate new ingredients, it: a) treats CPs as actual bosons which as distinct from BCS pairs which strictly speaking are not bosons; b) includes 2hCPs on an equal footing with two-electron ones (2eCPs); and c) in the resulting ternary ideal boson-fermion (BF) gas natur-ally incorporates BF vertex interactions that drive forma-tion/disintegration processes of CPs. This leads to a phase diagram with two pure phases, one with 2hCPs and the other with 2eCPs, plus a mixed phase with arbitrary proportions of 2eCPs and 2hCPs. The special-case phase when there is perfect symmetry, i.e., with ideal 50-50 proportions between 2eCPs and 2hCPs, gives the usual unextended BCS-Bose crossover. But the extended crossover predicts Tc/TF values (with Tc and TF the critical and the Fermi temperatures) for some well-known conventional superconductors comparing quite well with experiment and, notably, much better than BCS predictions. In turn, these results are compared with theoretical curves associated with the extended crossover for the special case of perfect symmetry holding at n/nf = 1, where n is the total number particle density and nf is the number density of unbound electrons at T = 0. Remarkably, for 50-50 symmetry all extended-crossover results lie below the Bogoliubov et al. upper limit λBCS ≤ ½, where λBCS is the dimensionless BCS coupling constant; this affords corroboration of their limit.

Biography:

Ranjan Chaudhury received his PhD from TIFR (Mumbai, India) in 1988. Thereafter, he held Post-doctoral and Visiting Scientist positions at ICTP (Trieste, Italy), McMaster University (Hamilton, Canada), University of Minnesota (Minneapolis, USA), LEPES-CNRS (Grenoble, France) and BLTP-JINR (Dubna, Russia). He is at present Professor (Associate) at SNBNCBS (Kolkata, India). He has published about 40 papers in several internationally reputed journals and has 20 other scientific publications. He has won several awards and honours including publication of his biography in Marquis Who's Who in the World ( New Jersey, USA 1999 & 2011) , in Marquis Who's Who in Asia (New Jersey, USA 2007) and International Scientist of the Year ( IBC, Cambridge, Great Britain 2007).

Abstract:

The low-dimensional magnetic systems, particularly the quasi-two dimensional ones, are of paramount technological importance in the present times in view of the possible existence of vortices/anti-vortices and merons/anti-merons, characterized as topological excitations. Besides, they provide considerable challenges to condensed matter physicists, both theoreticians and experimentalists for their satisfactory microscopic understanding. In collaboration with other members of my research group, I have investigated the nature of magnetic correlations and spin excitations in layered XY-anisotropic ferromagnetic and anti-ferromagnetic spin ½ systems realized in K2CuF4 and La2CuO4, by a combination of phenomenological and field theoretical techniques. These methodologies include semi-classical Berezinskii-Kosterlitz-Thouless (BKT) phenomenology corresponding to the unbinding of topological excitations and coherent state based effective action approach to identify the topological excitations themselves. Our theoretical works were motivated by the occurrences of prominent “central peak”s in the dynamical structure function in the constant-q scan of the inelastic neutron scattering experiments performed on the above two materials. Our detailed study of the spin dynamics induced by the translational motion of the unbound topological excitations for temperatures above TBKT, supported by the experimental results, brings out the clear possibilities of the emergence of the novel phenomenon of “quantum BKT transition” in the above two systems, with the observed limitations of the conventional semi-classical phenomenology.

Biography:

Ioan Has has completed his license at Technical University of Constructions from Bucharest in 1965, where the Physics course was delivered by prof. Nicolae Barbulescu. He obtained PhD degree in Geotechnical and Foundation field, from TUCB, in 1979. He followed a doctoral Seminar in 1975 at International Mechanics Centre from Udine, Italy. He functioned as Professor at Geotechnical and Foundation Chair from TUCB and at Technical Disciplines Chair from Land Forces Academy, Sibiu. But now works as independent expert in constructions. He published over 110 papers (40 in physics) in reputed journals and participated at about 20 conferences (12 in physics).

Abstract:

This work is based on results obtained in our two previous series of articles. In first series, an error was found in Michelson’s analysis of interferometer experiment. But Einstein relied on it, while developing the SRT, eliminating ether from physics. Our results imply that ether can exist. In second series, we proposed and validated the hypothesis that Coulomb’s law would better describe the reality including ether, by adding other terms to the left/right of actual term in r-2 including a term in –lnr. So, the force existing between two distant dipoles, when computed with completed Coulomb’s law, depends on r-2, as in Newton’s law. Numerically, the two forces were practically equal, resulting that the gravitation consists of dipoles interactions. For ether’s structure, we proposed the HM16 model, in which the constituent etherons are placed in the nodes of a microcrystalline network, and manifesting forces of mutual attraction/rejection. The microparticles (MPs) consist of local zones of ether, where an energy intake induced a state of vibrations/vortexes. The vibrant MPs will transmit fundamental vibrations (FVs) in ether, which have a velocity cF. Stationary FVs do not transmit energy in the infinite ether, but FVs create interaction forces between MPs having electric/magnetic nature, giving gravitation. MP can expel/absorb an elementary special particle, the photon (F), which moves through ether with light speed (c). The Fs constitute electromagnetic waves, which transmit energy in ether. The F photon creates its FVs in ether (dual aspect). Admitting cF>c, cF corresponds to gravitational waves, resulting from dipole interaction between the MPs, given by completed Coulomb’s law. HM16 explains the nature of the electric field as volumetric ε strains and of the magnetic field as distortional γ strains of ether. HM16 also explains the various interactions between EM waves and MPs or collisions between MPs.

Biography:

Anant Raj received his Undergraduate Degree in Mechanical Engineering from the Indian Institute of Technology, Kanpur in 2010. He received a Master’s degree in Nuclear Engineering from the North Carolina State University, Raleigh in 2013 and continued to pursue a PhD degree under the guidance of Prof Jacob Eapen. During his graduate studies, he was introduced to the fascinating field of materials science and the intricacies of probing materials behavior using statistical mechanics and atomistic simulations. He received his PhD on phonon dynamics and beyond-phonon descriptors for energy transport in materials. He is currently working as a Post-doctoral Research Scholar at the North Carolina State University.

Abstract:

Phonon dispersion curves are important to the analysis of energy transport in semiconductor and insulator materials. Experimentally, they can be determined using neutron/x-ray scattering or Raman spectroscopy techniques that involve the interaction of phonons with different forms of radiation. Theoretically, under harmonic approximation, they can be computed from the dynamical matrix extracted from force constants. Time correlations of dynamic variables in the reciprocal space offer a rich theoretical setting for computing the phonon dispersion curves, particularly for systems with marked anharmonic interactions. Currently, there are two general methods using the time correlation approach. In the first, the phonon dispersion is calculated using the frequencies extracted from the zero time expectation value of the correlation of displacements in the reciprocal space; equipartition of energy between the phonon modes is implicitly assumed. In the second method, the frequencies obtained from the Fourier transform of the time correlation of velocities are used to compute the dispersion of phonon modes. While the equipartition approach is computationally fast, since it requires only the zero time correlations, the assumption of equipartition of energy between the modes can result in tangible errors, especially at lower temperatures. In contrast, the Fourier method is more accurate but requires long correlation times for resolving the frequencies, making this approach computationally expensive. In this work, we present a family of methods to compute the normal mode frequencies from the ratio of the expectation value of the correlation of conjugate variables at zero time. This approach is computationally as fast as the equipartition methods, but is also robust and works even in the absence of equipartition. We present two variants of this approach that are appropriate for use in atomistic simulations. In the first, the phonon dispersion curves are calculated using the ratio of the normal mode amplitudes for velocity and displacement while in the second they are computed analogously from velocity and acceleration. We further elucidate the attractiveness of the second approach entailing velocity and acceleration for systems exhibiting anisotropic and highly anharmonic vibrations. Although the approach involving velocity and displacement is known before, we derive a family of zero-point methods from statistical-mechanical first principles. Finally, we demonstrate the accuracy, efficiency, and robustness of the zero-point methods on model linear chains and graphene using atomistic simulations.

Biography:

D Schmeltzer has completed his PhD from TECNION ISRAEL INSTITUTE of TECHNOLOGY HAIFA, IRAEL. He has published more than 120 papers in reputed journals and has been serving as an editorial board member. Hi is completed his B.Sc., in Hebrew University and M.Sc. in Technion, D.Sc. Now he is working a Professor of Theoretical Condensed Matter Physics in the City University of New York, New York, USA.

Abstract:

We study a model for Weyl semimetals using the scattering matrix formalism. We take in account boundary condition. Due to the boundary, the self adjoint condition needs to be checked in order to insure physical solutions. Using the principle of minimal coupling, we identify the electron-photon Hamiltonian. The photoemission intensity is computed using the $S$-matrix formalism. The $S$-matrix is derived using an incoming photon state, and outgoing state of a photoelectron and a hole in the valence band. The photoemission reveals the valence band dispersion $epsilon=pm v k_{y}$ and $^{''}$Fermi arcs $^{''}$. We construct the scattering matrix due to the chiral anomaly and obtain the crossed section for the photon intensity. In the presence of phonon we obtain the scattering matrix for chiral phonons allowing to investigate the Raman scattering.

Biography:

Taro Toyoda has completed his D.Sc. from Tokyo Metroplitan University and Research Associate at National Research Council of Canada. He is a Project Professor of University of Electro-Communications. His research focuses on basic studies of optical properties in semiconductor quantum dots including photoexcited carrier dynamics and their applications to photovoltaic solar cells. He has published more than 200 papers in reputed journals.

Abstract:

Semiconductor quantum dots (QDs) have been studied for their light harvesting capability. Although, a major breakthrough in conversion efficiency of QD-solar cells has yet to be reported. The reason is lack of fundamental understanding of the surface chemistry of QD. For QDs on TiO2, the heterogeneity can be caused by distributions of a number of properties of TiO2 and QDs. Their complecities hinder the understanding of important factors that control the photoinduced interfacial electron transfer (PIET). Herein, we report a stydy of PIET dynamics of CdSe QDs on well characterized single crystal rutile-TiO2 . To characterize the adsorption of CdSe QDs on single crystal rutile-TiO2, we used photoacoustic (PA) spectroscopy. Photoelectron yield (PY) spectroscopy was applied to characterize the valence band maximum of the TiO2 single crystals. The position of VBM for (111) surface is higher than those for the (110) and (001) surfaces. Transient grating (TG) method was applied to study the PIET dynamics. Basically, TG method depends on the refractive index changes due to photoexcited carriers. Pump beam was set at a wavelenght of 500 nm with a pulse width of 150 fs and probe pulse (775 nm) was delayed by an optical delay line (0 - 400 ps). The PIET rate constant of CdSe QDs increases with the increase of free-energy change. The change of the PIET rate constant on the (111) surface is higher than those on the other surfaces, indicating the difference in crystal binding and the overlap of wave fundtions at the QDs/TiO2 interface.

Biography:

Ke Xia has completed his PhD from Nanjing University and Postdoctoral studies from TU Delft and Twente University, Applied Physics department. He is the Head of Department of Physics, BNU China since 2011. He has published more than 80 papers in reputed journals.

Abstract:

Based on first principle study, we present the interlayer exchange coupling (IEC) affected by disorders in two types magnetic tunnel junctions (MTJ) structures: Fe/(MgO, Vacuum)/Fe (001) and Vacuum/Fe/(MgO, Vacuum)/Fe (001). Ferromagnetic coupling amplitude exponentially decrease with the barrier thickness, (surface case, disorder etc.)... We also study the interfacial disorder effects on the IEC through Fe/MgO/Fe(001) and Co0.5Fe0.5/MgO/Co0.5Fe0.5 (001) magnetic tunnel junctions (MTJ). As the sign and IEC amplitude across MgO-based MTJ were not consistent in the literatures, which was attributed to the presence of disorder hinted by local impurities model and supercell total energy analysis. Here, we employ the surface Green’s methods based on TBLMTO to obtain IEC strength, the coherent potential approximation (CPA) method is used to clarify IEC affected by several common types of disorder in MgO based MTJ, such as oxygen vacancy, Boron and Carbon impurities. We found that the character of IEC has strong dependence on the concentration, type and distribution of disorder.

Biography:

Kevin Storr earned a Ph.D. in Low Temperature Condensed Matter Physics from the Florida State University at the National High Magnetic Field Laboratory in Tallahassee Florida. He is currently an Associate Professor of Physics at Prairie View A&M University where he mentors undergraduate students in Physics research along with directing the thesis of graduate students. Professor Storr is a member of the Texas Physics Consortium and former faculty senator. Known as the Professor of Value, Dr. Storr conducts colloquia in areas of Value, Leadership, Science and Education and is the director of the newly formed, “Global Value Initiative.” He is a recipient of the International Golden Rule Award The Girma Wolde-Giorgis, Human Conservation Solutionist Award and serves as Special Advisor to the Office of the Ambassador at Large for the Republic of Burundi.

Abstract:

In the area of Condensed Matter, we use extreme environmental conditions of temperature (down to 20 millikelvin) and magnetic field (≤ 45 Tesla) to elucidate and tune the electronic, magnetic and thermal properties of candidate materials using several techniques. Three of our most commonly employed techniques are: electrical transport, magnetic torque cantilever and specific heat. Here we present results from three classes of materials, each studied using similar methods: organic conductors, heavy fermion systems and hybridized graphene. λ-(BETS)2FeCl4 is a quasi, two dimensional, layered, anisotropic organic conductor which has shown three states below liquid helium temperature: an antiferromagnetic-insulator state, metallic state, and a field induced superconducting (FISC) ground states with observed re-entrance. Nd1−xCexCoIn5 is 115 heavy fermion single crystal which exhibits unconventional superconductivity due to being an intermetallic compounds with large electron effective masses. This material can progress from having local moment magnetism to a heavy fermion with the gradual substitution of Nd with Ce. This leads to an adjustment of the availability of 4f electron coupling. Hybridized graphene and hexagonal boron nitride (h-BNC) domains as a disordered 2D electronic system was studied using magnetoelectric transport measurements. It clearly showed show an insulating to a metallic anomalous transition during the cooling process which we modulated with electron and hole-doping. It was concluded that in comparison to other 2D systems, that in h-BNC the transition came about from percolation associated with the metallic graphene and hopping conduction along edge states.

Biography:

Eugene Stephane Mananga is a Faculty Member in the Physics and Chemistry Doctorate Program at the Graduate Center of the City University of New York. He is an Assistant Professor of Physics and Nuclear Medicine at BCC of CUNY, and an Adjunct Professor of Applied Physics at New York University. Eugene completed his PhD in Physics from the Graduate Center of the University of New York, and holds 6 additional graduate degrees and training from various institutions including Harvard University, Massachusetts General Hospital (MGH), and City College of New York. Eugene did his postdoctoral studies in the National High Magnetic Field Laboratory of USA, Harvard Medical School, and Massachusetts General Hospital. Prior to joining Harvard - MGH, Eugene Mananga was an “Ingenieur de Recherche” in the French Atomic Energy Commission and Alternative Energies (CEA-SACLAY).

Abstract:

In this poster, we present the orders to which the Floquet-Magnus expansion (FME) and Fer expansion (FE) are equivalent or different for the three-level system. The third-order calculation is performed of both approaches based on elegant integrations formalism. As the propagator from the FME takes the form of the evolution operator, which removes the constraint of a stroboscopic observation, we appreciated the effects of time-evolution under Hamiltonians with different orders separately. Our work unifies and generalizes existing results of Floquet-Magnus and Fer approaches and delivers illustrations of novel springs that boost previous applications that is based on the classical information. Due to the lack of an unequivocal relationship between the FME and FE, some disagreements between the results produced by these theories will be found, especially in NMR experiments. Our results can find applications in the optimization of NMR spectroscopy, quantum computation, quantum optical control, coherence in optics, and might bear new awareness in fundamental perusals of quantum spin dynamics.

Biography:

Alexander Shimkevich has completed his PhD in 1982 from Institute for Physics and Power Engineering (IPPE), DS degree in 1998 from Institute for High Temperature of RAS, and full Professor in 2005. He has been employed by IPPE from 1971 to 2002 and by NRC Kurchatov Institute at present time. Prof. Shimkevich had over forty years of R&D experience in condensed matter physics for application to liquid metal technology and water chemistry of fast and thermal nuclear reactors. He has published more than 200 papers in reviewed journals and is serving as an editorial board member of "Atomic Eneger".

Abstract:

Though the band theory describes an electron population of energy bands on ideal crystal lattices, liquid dielectrics (pure water and molten salts) have the band structure too. It differs from bands in crystals by localization of electrons in "tails" of the allowed bands divided by a band gap. Just the band gap defines physical properties of dielectrics inasmuch as the allowed electronic levels near the bottom of conduction band (donors) and at the top of valence band (acceptors) change these properties. A position of such the impurity level in the band gap of liquid dielectric depends on its atomic concentration but its electron population depends on an electrochemical potential (Fermi level) in the band gap. This potential (as a p-n boundary between the vacant impurity levels and the ones occupied by electrons) becomes the management tool for physical and chemical properties of liquid dielectrics that is carried out by a "thin" shift of Fermi level in the band gap at the expense of an insignificant (<10-5) deviation of the chemical compound composition from the stoichiometric one. This deviation is homogenized in any liquid medium. Controllable shifts of Fermi level in the band gap of ionic and molecular melts as variations of their oxidation-reduction potential (ОRP) are theoretically studied including possibilities for managing their structural, physical and chemical, kinetic and corrosion properties. Correction of these properties by additives and selective extraction of fission products from the aqueous coolant and molten salts by shifting Fermi level are studied too.

Biography:

M A Swillam is Received his Ph. D from McMaster University, Hamilton, Canada in 2008. After graduation he worked as post-doctoral fellow in the same group. In October 2009, he joined the photonic group and the institute of optical sciences at the University of Toronto where he works as a research fellow. In September 2011, he was appointed as an assistant professor at the Department of Physics, the American university in Cairo (AUC). He is now an associate professor at the Department of physics at AUC, His research interests include design optimization and fabrication of active and passive nanophotonic and plasmonic devices and systems, silicon photonics, optical interconnects, integrated on- chip optical systems, lab on chip, nano-antenna, metamaterials, and solar cells. The main applications include biomedical systems, energy harvesting, and telecommunications. He authored more than 200 technical papers in highly ranked journals and conferences. He also hold 2 patents, a book, and book chapter in these areas.

Abstract:

This work presents the study and the design of optical ring modulator based on silicon-on-insulator ring resonator topped with silicon dioxide. The input and the output waveguides are separated from the ring resonator by a hybrid plasmonic waveguides in the coupling regions. The power-splitting mechanism is applying the external electric field to the hybrid plasmonic waveguides. The tuning mechanism takes the advantage of changing the refractive index of the modes and attenuating the power. The proposed ring modulator designed to operate under the telecommunication wavelength (1550 nm). A finite difference time domain method with perfect matching layer (PML) absorbing boundary condition is taken up to simulate and analyze the ring modulator. The main operations in digital signal processing are modulation and switching. The growing demand for high capacity signal processing systems made the assimilation of photonic circuitries into electronic circuitries. Optical signal processing systems and components concerned a lot of research. Optical ring resonators are among the fundamental components in optical systems since they can be used as modulators, filters, and sensors. Integrating indium-tin-oxide (ITO) with silicon electro-optic modulator has received enormous attention in the past few years because it’s electrically-induced epsilon-near-zero (ENZ) characteristics. The proposed modulator is based on silicon-on-insulator ring resonator topped with silicon dioxide. The input waveguide and the ring resonator are separated by a hybrid plasmonic waveguide in the coupling region, the same with the ring resonator and the output waveguide. The operation principle of this device is based on coupling the power from input waveguide to the ring resonator to the output waveguide. Tuning the optical power at the output waveguide is through applying electric field to the hybrid plasmonic waveguides, the generated carrier at the ITO layer results in changing the refractive indices of the even and odd modes of the input waveguide and the ring resonator. Moreover, it attenuates the coupling power to the ring resonator.

Biography:

Daniel Andres Triana Camacho received the B.S degree in Electronic Engineering from the Technological Units of Santander in 2014, Bucaramanga, Colombia. He is currently Msc. Physics student and researcher at the Science of Biology Materials and Semiconductors CIMBIOS group. His research interests include a design of biomedical devices, condensed matter, data processing, electrochemistry methods, pedagogy models and neural networks.

Abstract:

Big Data is defined in a variety of ways, including a) the search and retrieval of information to make decisions, and b) the science behind the data when these are used to respond any question. On other hand, chemical capacitance (a fundamental thermodynamic quantity related to charge accumulation at an electronic conductor/ionic conductor interface), is conventionally obtained by electrochemical impedance spectroscopy (EIS). Herein, current transients (CT) are proposed as an alternative measurement to determine the chemical capacitance. Thus, we describe a Python script to evaluate whether chemical capacitance can be obtained by CT collected at multiple potentials. The experimental procedure was performed with the redox pair Fe(CN)6 3-/Fe(CN)64-, a model one electron outer sphere process, and applied to the derivation of the chemical capacitance of the redox-activespecies on a Pt electrode. To validate the methodology here proposed is necessary to organize, process, and matching between these two different types of measurements, like so display information in the form of mathematical models, plots and files. Hence, we develop a protocol to analyze and compare a large amount of data irrespective of time scale. Usually, the experimental data for CT and EIS are analyzed independently and in differents ways by computational programs, for instance, repeating the sampling process for different times yields a family of curves named “sampled current-voltammograms”, one for each time scale. In addition, EIS data may be presented in several types of plots (e.g., Bode or Nyquist), which increase the volume of information obtainable from these measurements. Therefore, a getData class was created to get and process the experimental data from CT and EIS measurements. To process the experimental data a Python script was used to instantiate two objects: input and data objects. An input object is a JSON-like object where the file name and the potential for experiment data are defined, thereby JSON object was implemented as a Python dictionary. A data object is the instantiated getData object with the information contained in the data files referenced in the input object. A Python script containing the input and data objects was created to process experimental data of FeIII/FeII redox pair in solution. A total of 64 data files were obtained with NOVA 2.0 software for electrochemistry. Each CT data file contains approximately 15000 experiment numbers, and EIS, 305. With instantiate getData object the capacitance curves against potential from EIS and CT was constructed and compared in an easier way than process data with traditional tools used in electrochemistry. It is concluded that at a specific condition of time scale, the integral of CT and EIS measurements give similar results of capacitance.

Biography:

V S Filinov is Doctor Phys&Math. Sc., Prof.. Education: Moscow Power Engineering Institute, M. Sc.degree in Physical Optics, Moscow State University, M. Sc.degree in Mathematics. He is a principal researcher in Joint Institute for High Temperatures Russian Academy of Sciences. He has published more than 200 papers in reputed journals and has been serving as Organizing Committee Member of several International conferences.

Abstract:

The main difficulty for path integral Monte Carlo studies of Fermi systems results from the requirement of antisymmetrization of the density matrix and is known in literature as the ’sign problem’. To overcome this issue the new numerical version of the Wigner approach to quantum mechanics for treatment thermodynamic properties of degenerate systems of fermions has been developed. The new path integral representation of quantum Wigner function in the phase space has been obtained for canonical ensemble. Explicit analytical expression of the Wigner function accounting for Fermi statistical effects by effective pair pseudopotential has been presented. Derived pseudopotential depends on coordinates, momenta and degeneracy parameter of fermions and takes into account coordinate – momentum principle uncertainly. The new quantum Monte-Carlo method for calculations of average values of arbitrary quantum operators has been proposed. To test the developed approach calculations of the momentum distribution function of the degenerate ideal system of Fermi particles has been carried out in a good agreement with analytical Fermi distributions. On other hand the first results on influence of interparticle interaction on momentum distribution functions show appearance of quantum ”tails” in the Fermi distributions.

Biography:

Peng-Sheng Wei received Ph.D. in Mechanical Engineering Department at University of California, Davis, in 1984. He has been a professor in the Department of Mechanical and Electro-Mechanical Engineering of National Sun Yat-Sen University, Kaohsiung, Taiwan, since 1989. Dr. Wei has contributed to advancing the understanding of and to the applications of electron and laser beam, plasma, and resistance welding through theoretical analyses coupled with verification experiments. Investigations also include studies of their thermal and fluid flow processes, and formations of the defects such as humping, rippling, spiking and porosity. Dr. Wei has published more than 80 SCI journal papers, given keynote or invited speeches in international conferences more than 120 times. He is a Fellow of AWS (2007), and a Fellow of ASME (2000). He also received the Outstanding Research Achievement Awards from both the National Science Council (2004), and NSYSU (1991, 2001, 2004), the Outstanding Scholar Research Project Winner Award from National Science Council (2008), the Adams Memorial Membership Award from AWS (2008), the Warren F. Savage Memorial Award from AWS (2012), and the William Irrgang Memorial Award from AWS (2014). He has been the Xi-Wan Chair Professor of NSYSU since 2009, and Invited Distinguished Professor in the Beijing University of Technology, China, during 2015-2017.

Abstract:

The molten pool or fusion zone shape and transport variables affected by thermocapillary force during melting or welding with a distributed energy beam can be scaled as functions of specified working variables. pool. The scaling analysis considers different thicknesses of thermal and momentum boundary layers in different regions in the molten pool. Incident flux is irradiated in the central region of the free surface. The driving force is thermocapillary force balanced by shear stresses in the shear layer below the free surface. The scaling results are found to agree well with experimental data and numerical computations for different Prandtl numbers, as shown in Figure 1. Figures 2 and 3 show that scale analysis of the fusion zone depth and width agree well with numerical computations.

Biography:

Alex Guskov received a Ph.D. degree in 1982 in Physical Institute of the Russian Academy of Sciences. Then A.Guskov went to work in Institute of Solid State Physycs the Russian Academy of Sciences, investigated the influence of interaction of laser radiation and a solid. Simultaneously he was engaged in application of technological processes in manufacture of electronic devices. Now his research interest focuses on heat mass transfer during the phase transition.

Abstract:

The modern theory of phase transitions cannot explain the results of many experiments of interphase mass transfer. One reason for this is the assumption that during crystallization the solution is in the metastable state. The purpose of this study to show that in many cases the solution during crystallization can be an unstable state. The unstable condition leads to decomposition the solution by spinodal scenario. The unstable solution decomposes continuously in the whole volume in this case. Experimental demonstration of spinodal decomposition of the solution is conducted video shooting process of decomposition of an aqueous solution of bromthymol blue while its crystallization. Locally - configuration thermodynamic model is used to explain the state changes of the solution during the phase transition. Spinodal decomposition of the solution explains the process of formation of a periodic distribution of the eutectic composites. The layer of the unstable solution is localized in front of the unstable interface. The unstable solution decomposes into phases, which have a composition close to the eutectic composition of the solid phases. The period of alternation of these phases is set by the period of instability of the interface. Experiments show that the formation of dendrites in the mushy zone and extremum of the component concentration during steady-state regime of crystallization close to interface also occurs in the spinodal decomposition scenario. Spinodal decay during crystallization solutions can be used for their separation into the eutectic phase.

Biography:

Peter P Pershukevich, Victoria A Lapina and Tatiana A Pavich – scientific employees of the Institute of Physics of National Academy of Science of Belarus. Dr.V. Lapina has PhD in chemistry, leading scientific researcher. The main direction of her work is biomedical optics and nanotechnologies. She is authors more than 200 scientific papers, 20 patents. Dr. T. Pavich has PhD in chemistry, senior research scientist, specialist in the synthesis of complex compounds of lanthanides. She is authors more than 100 scientific papers, 3 patents. Dr. P. Pershukevich has PhD in physical and mathematical sciences, deputy head of the scientific center, specialist in spectroscopic research, especially luminescence methods, various radiating materials: porous silicon and porous aluminum, inorganic and organic luminophores activated with lanthanides, and others. He is the author of more than 150 scientific papers, 8 patents.

Abstract:

Complex compounds of lanthanides have been extensively studied for many years and interest in them is increasing due to their unique optical properties and a wide range of applications. With the development of nanotechnology, new opportunities appeared in the development of complex compounds of lanthanides with new properties. Particularly important among them are thermal and radiation stability, volatility in vacuum, photostability, durability, homogeneity, etc. Many methods for modifying lanthanide complex compounds, in particular europium (III), have been described in the literature. In the present work, an attempt has been made for the first time to modify coordination compounds by synthesis of nanostructured supramolecular complexes of europium (III), in which nanodiamonds were used as templates. As the initial coordination compounds, two well-tested multiligand complexes of europium were used: the first with tris(tenoyltrifluoroacetonate) and 1,10-phenanthroline (Eu (TTA)3Phen) (also EuT); the second with bathophenanthroline and NO3 groups (Eu (BPhen)2(NO3)3) (also EuB). The totality of the data obtained by us on electron scanning microscopy, spectral-luminescent characteristics, IR and EPR spectra clearly indicates the formation of new complexes with ND as a result of targeted synthesis. Its physicochemical properties differ significantly from those of the initial coordination compounds. It has been revealed that the advantages of complexes with nanodiamonds are: higher photostability (2-3 times), a spectrum with predominant emission in one narrow band 5D0-7F2 (~ 615 nm), a higher luminescence brightness when excited in the far UV region of the spectrum. New luminescent complexes of lanthanides with ND in the composition of polymer matrices can be used: as luminescent substances in OLED; as active materials for detectors and dosimeters of ionizing radiation; as active laser media.