2^nd International Conference and Exhibition on Mesoscopic and Condensed Matter Physics October 26-28, 2016 Chicago, USA

Biography:

Stuart Tessmer completed his PhD in 1995 at the University of Illinois at Urbana-Champaign (UIUC); he studied as a postdoc at the Massachusetts Institute of Technology (MIT) from 1995-1998. At Michigan State University he specializes in experimental condensed matter physics and is currently the Physics Department Associate Chair & Undergraduate Program Director.

Abstract:

In this talk I will present scanning tunneling microscopy data of a Bi₂Se₃ crystal with superconducting PbBi islands deposited on the surface. Local density of states measurements show induced superconductivity in the topological surface state with a coherence length of order 540 nm. At energies above the gap the density of states exhibits oscillations due to scattering caused by a nonuniform order parameter. Strikingly, spectra taken on the superconductor side of the  interface show Dirac-cone-like behavior suggesting an inverse proximity effect – that is topogical states induced onto the superconductor.

Biography:

Louis H Kauffman received  a B.S. in Mathematics from MIT in 1966 and a PhD in Mathematics from Princeton University in 1972. He has taught at the University of Illinois at Chicago since 1971 and has been a Full Professor since 1984. He is the Editor in Chief of the Journal of Knot Theory and Its Ramifications and the editor of the World Scientific Book Series on Knots and Everything. He is a Fellow of the American Mathematical Society since 2014. He is past president of the American Society for Cybernetics and the recipeint of the Warren McCullocy Award (1993) and the Norbert Wiener Gold Medal (2014) of that Society. He is the 2015 recipient of the Bertalanffy Medal for Significant Contributions to Complexity Thinking. Kauffman is the author of numerous books on knots and their applications. His resarch is primarily focused on the structure and discovery of topological invariants of knots and links.

Abstract:

Majorana fermions are Fermionic particles that are their own anti-particles. Mathematically, a standard fermion such as an electron can be seen as a composite of two Majorana fermions. At the level of operators in quantum field theory this is seen by writing F = a + ib where F is the fermion annihilation operator and a and b are elements of a Clifford algebra where a^2 = b^2 = 1 and ab = -ba. Then F* = a - ib and we have FF = F*F* = 0 and FF* + F*F is a scalar, the usual fermion relations. Remarkably, rows of electrons in nanowires have been shown to have correlation behaviors that corresponds to this decomposition, and topologically remarkable is the fact that the underlying Majorana fermions have a natural braiding structure. This talk will discuss the braiding structure of Majorana fermions and possible applications to topological quantum computing

Biography:

Junji Haruyama graduated from Waseda University, Tokyo, Japan in 1985. Right after that, he joined Quantum device laboratory, NEC Corporation, Japan and worked until 1994. He received PhD in Physics from Waseda University in 1996. During 1995–1997, he worked with the University of Toronto, Canada (Prof. J Xu Lab), and also Ontario Laser and Lightwave Research Center, Canada as a Visiting Scientist. Since 1997, he has worked at the present Aoyama Gakuin University as a Professor until now. He was also a Visiting Professor at NTT Basic Research Laboratories (Dr. Takayanagi’s Nano-science Lab), Institute for Solid State Physics (Prof. Iye’s Nano-science Lab), The University of Tokyo, and Zero-emission Energy Center, Kyoto University, Japan. He has been a Principal Researcher at Air-Force Office of Scientific Research, USA since 2010. He has peer review publications of over 100 and 4 patents, and has also done more than 150 invited talks. He has been Co-author of over 30 books, a Referee of over 50 journals and a Member of international committees (organizer, adviser and chairman) of over 30 conferences.

Abstract:

Two-dimensional (2D) atom-thin layers have attracted significant attention after the discovery of primitive fabrication method of graphene, mechanical exfoliation of graphite using scotch tapes. As a van-der Waals engineering, various atom- thin layers and those hybridization have been recently realized. In the talk, first, I will present magnetism and spintronics arising from edges of 2D atom-thin layers, graphene, few-layer black phosphorus (BP) and hexagonal boron-nitride (hBN). I created nanomesh (NM) structures, consisting of honeycomb like array of hexagonal pores, with specified pore-edge atomic structure (i.e., zigzag type) on individual layers. Interestingly, hydrogen-terminated graphene NM (H-GNM) shows flat-band ferromagnetism, while it disappears in oxygen-terminated GNM. On the other hand, O-BPNM exhibits large ferromagnetism due to ferromagnetic spin coupling of edge O-P bonds, whereas it is eliminated in H-BPNM. O-hBNNM also shows large ferromagnetism due to edge O-B and O-N bonds, while it disappears in H-hBNNM. These are also highly sensitive to annealing temperatures to form zigzag pore edge. These open a considerable avenue for realizing 2D atom-thin flexible magnetic and spintronic devices, fabricated without using rare-earth magnetic atoms. Second, I will show creation of the world-thinnest Schottky junction on few-layer molybdenum disulfide (MoS2), one of the transition metal dichalcogenides. The 2H-phase of MoS2 has direct band gaps of 1.5−1.8 eV. It is demonstrated that electron-beam (EB) irradiation to the 2H-phase causes semiconductor- metal transition to 1T-phase and atomically-thin Schottky junction with barrier height of 0.13−0.18 eV is created at the interface of 2H/1T regions. These findings also indicate a possibility that the effective barrier height is highly sensitive to electrostatic charge doping and almost free from Fermi-level pinning when assuming predominance of the thermionic current contribution. This EB top-down patterning opens the possibility to fabricate in-plane lateral heterostructure FETs,which have shown promising scaling prospects in the nanometer range, and/or local interconnects directly with metallic phase (1T) between (2H)MoS2 transistors, resulting in ultimate flexible and wearable in-plane integration circuits without using 3D metal wirings. Finally, I will also briefly talk about introduction of spin-orbit interaction into graphene by light hydrogenation(<0.1%).

Biography:

Igor Tralle is a physics professor at the Faculty of Mathematics and Natural Sciences, University of Rzeszów. His research interests are concentrated around Solid State and Semiconductor Physics, charge carrier transport in low-dimensional and quantum structures, linear and nonlinear Optics, quantum cascade lasers as well as Mathematical Physics. During the last couple of years his research interests are moving also towards THz detection and generation and metamaterials. He is an author or co-author of about 100 research papers published in high-rank peer reviewed scientific journals. Close

Abstract:

The field of research termed as Quantum Information Theory and more specifically, Quantum Computation  attracts nowadays a great deal of attention. Recently Di Vincenco [1] proposed what was called Di Vincenzo's check list, the list of requirements  the quantum system has to fit in, for one has the possibility to implement on such a basis the quantum computer, the Holy Grail of those who deal with quantum information and quantum computation. These requirements are: (i) well defined qubits; (ii) relatively long decoherence times (iii) initial state preparation and some others equally important.  The aim of our work is to advance new approach to producing the qubits  in electron ballistic transport in low-dimensional structures such as double quantum wells or double quantum wires (DQW). The  qubit would arise as  a result of quantum entanglement of two specific states of electrons in DQW-structure. These two specific states are the symmetric and anti-symmetric (with respect to inversion symmetry, or mirror image) states arising due to tunneling across the structure, while entanglement could be produced and controlled by means of the source of  non-classical light. Thus, in such structure one can get the two-particle pure states entanglement: in our case two subsystems are the electron (subsystem A ) which can be either in the state  or in the state and the photons (subsystem B). The state is the product state if there exist  such that, otherwise the state is called entangled . The product states are: where  is associated with symmetric electron state and  with the EM-field state characterized by the number of photons n and , where  is associated with anti-symmetric one and  with the EM-field state characterized by the number of photons n-1, whereas  entangled states   in our case are : We examined the possibility to produce quantum entanglement in the framework of Jaynes-Cummings model and have shown that the entanglement can be achieved due to striking and unusual phenomena related to Jaynes-Cummings model, namely series of ‘revivals’ and ‘collapses’ in the interaction of a quantized single-mode EM-field with a two-level system.

Biography:

Gayan Prasad Hettiarachchi completed his PhD in Physics at Osaka University in 2015. He is currently working as a specially-appointed assistant professor at the Insititute for NanoScience Design at Osaka University. He is interested in experimentally investigating strongly-correlated electron systems in order to elucidate vital correlation effects and the underlying mechanisms that ultimately lead to interesting physical properties and phase transitions.

Abstract:

Insulator-to-metal transitions (IMTs) still remain a central theme in condensed-matter physics despite many zealous experimental and theoretical efforts. The persistence of this question for decades can be attributed to the complexities that arise due to strong correlation-effects and many degrees of freedom that exist in real systems. The seminal work of Mott introduced insulating character originating from strong on-site Coloumb repulsion energy U. The ratio of U and Hubbard bandwidth W (U/W) is a critical parameter that tips the balance of insulating and metallic states. However, in real systems, correlation effects are not limited to these two parameters, and effects from intra-atomic exchange energy, orbital degeneracy, crystal-field splitting, etc., come into the equation. For electrons in a deformable lattice, electron-phonon interaction energy S and the induced deformations become crucial parameters that govern the evolution of the trasfer integral t. Aluminosilicate zeolites (M_aAl_aSi_bO_2(a+b)) provide an ideal, but non-trivial playground for exploring such interactions. The negative charge of Al_aSi_bO_2(a+b) framework is balanced by the cations M_a and present a deformable lattice. Guest electrons can be introduced into this deformable lattice through encapsulation of guest atoms. Experimental investigations show that even with same/comparable effective U, subltle changes in the deformable lattice (in turn change in the deformation potential), and tuning of S by changing M can give rise to different ground states. The competition between U, t, and S together with the electron density govern the balance between insulating vs. metallic states and magnetic vs. nonmagentic states directing the dscussions of IMTs towards a relatively old but less discussed branch, the “polaron physics”.

Biography:

Haifeng Song has completed his PhD from Tsinghua University. He is Director of research group in the fields of condensed mater physics and material physics. His research interests include the equation of state, phase transition, transport properties of metals, etc. He has published more than 40 papers in reputed journals and has been serving as an Editorial Board Member of repute.

Abstract:

The thermodynamic stable phase of cerium metal in the high pressure regime has been studied by combining density functional theory with the Gutzwiller variational approach (LDA+Gutzwiller), which can include the strong correlation effect among the 4f electrons in cerium metal properly. Our numerical results show that the α″ phase, which has the distorted body-centered-tetragonal structure, is the thermodynamic stable phase in the intermediate pressure regime (5.0-13.0 GPa) and all the other phases including the α′phase (α-U structure), α phase (fcc structure) and bct phases are either metastable or unstable. Our results are quite consistent with the most recent experimental data. We also studied the α-γ iso-structure transition in cerium, we found that the first order transition between α and γ phases persists to the zero temperature with negative pressure. By further providing a newly finite temperature generalization of the LDA+G method (using the mean-field potential approach), the entropy contributed by both electronic quasiparticles and lattice vibration included, we obtain the Gibbs free energy at a given volume and temperature, from which we get the α-γ transition at finite temperature and pressure. Our results indicate that the electronic entropy and lattice vibrational entropy both play important roles in the α-γ transition. We also calculated the equation of state and phase diagram of cerium, finding good agreement with the experiments.

Biography:

S C Wang has completed his PhD from Tsinghua University. He is a Research Fellow in the fields of Condensed Mater Physics and Material Physics. His research interest includes the equation of state, phase transition and transport properties of metals. He has published about 10 papers in reputed journals.

Abstract:

Increasing demands to subsequent design and engineering of new high performance materials are boosting the precise knowledge of melting and transport properties of metals. Here we report an ab initio molecular dynamics study of melting and diffusion coefficients of aluminium under high pressure. The melting curve up to 400 GPa is predicted from the twophase method, which has a good agreement with experiments and other calculations. The diffusion coefficients up to 140 GPa and 10000 K are obtained from the mean square displacements and the autocorrelation functions of atomic velocities via the Green-Kubo relation, which reveal that the original entropy-scaling law is violable, but an exponential relationship still exists between the dimensionless diffusion coefficients and the pair correlation entropy.

Biography:

Hongzhou Song has obtained a Doctor of Philosophy Degree (PhD) in Theoretical Physics from China Academy of Engineer Physics. He is Associate Research Fellow of Institute of Applied Physics and Computational Mathematics.

Abstract:

Actinide compounds have been attracting scientific attentions because of their industrial, military, and environmental importances, as well as the vast theoretical prospects around the intriguing 5f electrons. In comparison with lots of studies extensively on actinide oxides aiming to reveal their ground-state properties as well as the electronic behaviors under pressure, the hydrides of actinide elements receive much less concerns. This is probably because that actinide oxides are always very stable at ordinary conditions, while actinide hydrides are easily oxidized within the earth’s atmosphere. However, hydrides
are also very important to the atmospheric corrosion of actinide metals. Recently, several researches turn their interests into electronic structures and physical properties of hydrides such as PuHx and UH3. The electronic structure and properties of α and β uranium hydride and deuteride under extreme conditions are investigated within the DFT and DFT+U formalisms. It is found that both αand β-UH3 are ferromagnetic in their ground states.Applying stretching strains does not change the groundstate magnetic ordering and the atomic magnetization around each uranium atoms. In contrast,compression strains will enhance the covalency character of the U-H bonds and transform UH3 into nonmagnetic states. The underlying electronic reasons are carefully analyzed through Bader charge calculations and electronic wavefunction analysis. Our obtained physical results accord well with previous studies, and serve as a reference for understanding the electronic behaviors of other actinide
materials under compression.

Biography:

C S Ting is a professor of physics at the University of Houston. His major research area has been on theoretical condensed matter physics including transport theories in various solid state systems, superconductivity in copper oxide materials and iron pnictides, magnetism, metal-insulator transition, electronic property of graphene, solids with the spin-orbit couplings, and strongly correlated electron systems. He is the principal investigator in theory at the Texas Center for Superconductivity at the University of Houston, and a fellow of APS in the Division Condensed Matter Physics. 

Abstract:

Fully- and semi-hydrogenated graphene, named graphane (C₆H₆)^1,2 and graphone (C₆H₃)^3,4, were previously found to be nomagnetic semiconductor with a direct gap of 3.5 eV and antiferromagnetic semiconductor with an indirect gap of 2.46 eV, respectively. Here, by means of first-principles calculations, we predict another kinds of partially hydrogenated graphene systems⁵: C₆H₁ and C₆H₅, which are ferromagnetic (FM) semimetal and FM narrow-gaped semiconductor with an indirect gap of 0.7 eV respectively. When properly doped, the Fermi surface of the two systems consists of an electron pocket or six hole patches in the first Brillouin zone with completely spin-polarized charge carries. If superconductivity exists in these systems, the stable pairing-symmetries are shown to be p + ip for electron doped case, and anisotropic p + ip for hole doped case. The predicted systems may provide fascinating platforms for studying the novel properties of ferromagnetism and triplet-pairing superconductivity.  In addition, the electronic structures of hydrogenated graphene C₆H₂ and C₆H₄  have  also been studied. We find that C₆H₂ is a Dirac semimetal with 2 highly anisotropic cones located well inside the first Brillouin zone,  and C₆H₄ is a semiconductor with a gap of ~3.35 eV. A detailed discussion of their properties will be presented.

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 solid state 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 Ph.D., M.Phil., M.Sc., and M.Tech. projects. She has over 50 international publications. She is the recipient of various awards and prizes for her academic and research contributions.

Abstract:

Silicene, germanene, and tin; the 2D analogues of graphene are structurally different from graphene due to the buckling distorsions in the lattice. Hybridization in graphene is purely sp². It is sp²/sp³ mixed orbitals in other 2D structures that results in buckling and causes pronouced effects in their properties. Structural, electronic, optical and mechanical properties are investigated. Density Functional Theory with Generalized Gradient Approximation as implemented in CASTEP is used. At the Dirac point, the dispersion curve is linear in graphene and quadratic in all other materials. Critical points, saddle points, Van Hove singularities are investigated in band structures and density of states histograms. Optical properties unveil the frequency dependence and non linear response of absorption. Graphene exhibits  prominent aborption in the ultraviolet region and shifts towards the infrared region in all other 2D structures.  Intensity of absorption increases in layered structures. Birefringence is exhibited by single and layered structures. Real part of refractive index establishes the anisotropic behaviour. Bilayer exhibits semimetallic behaviour. Trilayer portrays metallic nature. Study on mechanical properties brings out the unique stiffness of graphene. Bonding characteristics and  charge density contours endorse that covalency reduces from graphene to stanene, due to which elastic moduli decreases from graphene to stanene. Poisson’s ratio shows increased brittleness in graphene, semimetallic nature in silicene and germanene, and metallic nature in stanene. Although silicene, germanene, and stanene posses only 20%, 14%, and 9%  of Young’s modulus, the bonding nature facilitates its suitability in semiconductor industry along with substrates to enhance the conduction mechanism.

Biography:

P M Trivedi is presently working as an Associate professor at Bhavan’s Sheth R. A. College of science, affiliated to Gujarat University, a UGC India recognised university. He completed his Ph.D. in2004 from Bhavnagar University. He has assisted some government educational institutes for syllabus designing as wel as laboratory establishments for under graduates and research purpose. Though he is mainly involved in UG nd PG teaching, he has played key role in cultural activities of the college and done career counselling for a large number of students.

Abstract:

A magnetic liquid also called Ferro Fluid[1], is a colloidal dispersion of surfactant coated ferrite particles of nano-size. The behavior of such fluid is of super-paramagnetic nature[2]. In such diluted continnum micron size graphite particles were dispersed. This created magnetic holes [3]. As their size varies, their coagulations in the form of particle chains under external magnetic field is also affected. Light transmitted through thin films of such materials exhibit birefringence. Experimentally observed extinction parameters are reported to have reversal effects [4-5].  Role of gradient density distribution of anisotropic magnetic particles is discussed for the observed phenomenon. Necessary theoretical model is developed and compared with the experimental data.

Biography:

Anamika Vitthal Kadam has completed her PhD at the age of 31 years from Bharti Vidyapeeth University, Pune, MH, India. She is working as Assistant Prof in D.Y. Patil Engg and Tech, Kolhapur, MH, India and having guideship of D.Y. Patil University. Se has published more than 25 papers in national and international journals and achieved a project under young scientist scheme with one minor research project.

Abstract:

The electrochromic properties of organo-inorganic hybrids of WO3/PPy thin films have been synthesized with a two step processes successfully. The WO3 layer was prepared by electrodeposition technique on conducting glass substrate (Indium doped Tin Oxide-ITO) followed by thermal treatment and polypyrrole thin films were deposited using chemical bath deposition (CBD) technique. The structural, morphological, optical and electrochromic responses of WO3, PPy and WO3/PPy films are described. To study the electrochromic (EC) properties of the as deposited films, cyclic voltammogram (CV), chronoamperometry (CA), hronocoulometry (CC) and optical modulation were performed. The kinetic investigation (response time) and coloration efficiency were found to be enhanced appreciably. The WO3/PPy shows improved EC performance than their solitary act.

Biography:

Nan Xu has completed his PhD in 2013 from Institute of Physics, Chinese Academy of Sciences. Afterwards, he conducted his postdoctoral studies at Swiss Light Source, Paul Scherrer Insitut in 2013-2015, and at Ecole Polytechnique Federale de Lausanne (EPFL) from 2015 to now. His academic insterests are using angle-resolved photoemission spectroscopy to study the strongely correlated systems and novel quantum states. He has published more than 30 papers in reputed journals over past 5 years, and been invited speaker in more than 10 international conferences.   

Abstract:

Recently, significant advances in topological theory extend the topological classifications from non-interacting insulators to strongly correlated insulators, and further to semimetals. In this talk, I will report our recent works about direct visualizations of topological quantum states with angle-resolved photoemission spectroscopy (ARPES), including:

• The observation of energy-band dispersions [1-2] and spin texture [3] of the metallic surface states on SmB₆ as compelling evidences for the predicted strongly correlated topological kondo insulator states.
• Experimental realization of Weyl semimetal states in TaAs by direct observation pairs of 3D Weyl cones in the bulk states [4], matching remarkably well with our first-principles calculations.
• Experimentally realization of ideal Weyl semimetal state in TaP, where only single type of Weyl fermions contributing the exotic transport properties [5].
• Discovery first type-II Weyl semimetal state in MoTe₂ in wihch Fermi surfaces consist of a pair of electron- and hole- pockets touching at the Weyl node and Weyl fermions strongly violate Lorentz invariance [6].
• Preliminary results on new topological quantum states.

Biography:

Pavel Belov received his PhD from the University of Hamburg in 2010. He is a teaching assistant at the Department of Physics of the St.Petersburg State University. He has published more than 20 papers in the reputed journals and conference proceedings.        

Abstract:

Excitons states and exciton light-coupling in bulk semiconductors and heterostructures have been under intensive study in the last few decades. Although the exciton binding energy is relatively small in the bulk semiconductors, typically lower than the lattice vibration energy at room temperature, in the semiconductor heterostructures it can increase significantly, up to several times. The radiative properties of an exciton are characterized by the radiative decay rate, which is defined by the exciton-light coupling. In our study, the binding energy and the corresponding wave function of excitons in GaAs-based finite square quantum wells (QWs) are calculated by the numerical solution of the three-dimensional Schroedinger equation. The precise results for the lowest exciton state are obtained by the Hamiltonian discretization using the high-order finite-difference scheme. The calculations are compared with the results obtained by the standard variational approach. The exciton binding energies found by two methods coincide within 0.1 meV for the wide range of QW widths. The radiative decay rate is calculated for QWs of various widths using the exciton wave functions obtained by direct and variational methods. The radiative decay rates are confronted with the experimental data measured for high-quality GaAs/AlGaAs and InGaAs/GaAs QW heterostructures grown by molecular beam epitaxy. The measurements and results of calculations are in good agreement.

Biography:

Claire Levaillant graduated with a Ph.D. from California Institute of Technology in 2008. She has since then occupied visiting positions at Harish Chandra Research Institute in India and at the University of California at Santa Barbara in the USA. While in Santa Barbara she worked with the Microsoft Research Station Q team. She has authored papers in the fields of group theory and quantum computation.

Abstract:

Exotic particles named Fibonacci anyons have drawn increasing interest for topological quantum computation. Their specificity is the density of the braid group representations (Freedman-Larsen-Wang, 2001), that is any quantum gate can be approximated by braiding of the anyons, up to some arbitrary precision. In this talk, we show how adding measurement operations allow making some exact quantum gates probabilistically. From these probabilistic quantum gates, we derive exact ancillas, which we use in turn to make exact key quantum gates. Many recent theoretical studies have shown evidence for the existence of these exotic particles and have exhibited experimental platforms for their use. The field is vibrant on-going theoretical and experimental research in condensed matter physics.

Biography:

Qili Zhang has completed his PhD China Academy of Engineering Physics. He is a Research Fellow in the fields of Condensed Mater Physics and Computational Physics. His research interests include the equation of state, phase transition and transport properties of materials. He has published about 10 papers in reputed journals.

Abstract:

The T=300 K isotherm of diamond is calculated by using density-functional molecular dynamics. The results show that the PAW-PBE potential is more close to the experimental data. The thermodynamic states accessible under shock conditions are given by the principal Hugoniot which satisfying the Rankine-Hugoniot equations, the internal energy and pressure at a given density and temperature are calculated by using density-functional molecular dynamics, the initial state was taken to be un-shocked diamond with ρ₀=3.475 g/cm³, T=300 K, and P₀≈0GPa, which obtained from the T=300 K isotherm. Our principal Hugoniot is similar with the result of Nichols in the literature, but is little higher in pressure and temperature, the solid-liquid coexistence region is from ρ=6.0 g/cm³ to 6.95 g/cm³. Knowledge of the sound velocity is essential for a variety of research areas; moreover, the pressure and temperature dependence of the sound velocity can be used to constrain the equation of state. This work presents two theory methods to calculate the sound velocity of solid phase along the principal Hugoniot: One by using the Gruneisen equation state and the isotherm at T=300 K, the other by using the specific heat, the pressure derivative with respect to the density and to the temperature along the principle Hugoniot, the results are consistent with each other. The optical reflectivity of the diamond on the principal Hugoniot is also calculated, the result is consistent with the experimental results in the literature.

Biography:

Claire Levaillant graduated with a Ph.D. from California Institute of Technology in 2008. She has since then occupied visiting positions at Harish Chandra Research Institute in India and at the University of California at Santa Barbara in the USA. While in Santa Barbara she worked with the Microsoft Research Station Q team. She has authored papers in the fields of group theory and quantum computation.

Abstract:

Exotic particles named Fibonacci anyons have drawn increasing interest for topological quantum computation. Their specificity is the density of the braid group representations (Freedman-Larsen-Wang, 2001), that is any quantum gate can be approximated by braiding of the anyons, up to some arbitrary precision. In this talk, we show how adding measurement operations allow making some exact quantum gates probabilistically. From these probabilistic quantum gates, we derive exact ancillas, which we use in turn to make exact key quantum gates. Many recent theoretical studies have shown evidence for the existence of these exotic particles and have exhibited experimental platforms for their use. The field is vibrant on-going theoretical and experimental research in condensed matter physics.

Biography:

Prof. Rao had a brilliant academic record at Andhra University where he got the B.Sc (Honors), M.Sc and D.Sc degrees and also taught for two years. He spent two years each at Duke and Harvard Universities as postdoctoral fellow. He has been teaching at the University of Massachusetts, Boston since 1968 where he is currently Distinguished Professor in the Physics Department. He was elected a Fellow of the American Physical Society, Division of Laser Science in 2010 "in recognition of a long record of significant contributions to the nonlinear optics of organic materials and their applications to optical power limiting, Fourier phase contrast microscopy and medical image processing". He published over 120 papers in peer reviewed prestigious journals like Physical Review Letters, Applied Physics Letters, Optics Letters etc. covering research areas- nonlinear optics, magnetic resonance, microwave absorption, optical Fourier techniques for breast cancer diagnostics, phase contrast and multimodal optical microscopy etc. He holds ten patents and one of these on Fourier Phase Contrast microscopy is recently licensed to industry for marketing the technology.

Abstract:

We have been working on basic nonlinear optics of the protein complex Bacteriorhodopsin (bR) thin polymer films with milliwatt cw lasers. The unique feature of this material is its flexibility. Absorption of a visible photon by bR triggers the photo cycle, starting from the initial B state to the relatively long lived M state via short lived intermediate states. It can revert to the initial B state thermally in milliseconds via short lived intermediate states or can go back directly to B state within nanoseconds by shining blue light. Both life times can be altered by orders of magnitude using chemical methods or genetic mutation. The process of switching between B and M states (chemical isomers) can go in both directions depending on wavelength, intensity and polarization of the incident light offering a variety of possibilities for manipulating amplitude, phase and polarization. Over the years we studied the basic nonlinear optics- four wave mixing, phase conjugation, photo induced anisotrpy etc. We successfully exploited the unique properties for many applications- all optical switching, modulation, computing, information processing, power limiting for laser eye protection, medical image processing, transient Fourier holography etc. More recently we are focusing on optical Fourier techniques for early detection of micro calcifications in mammograms for breast cancer diagnostics. We also developed an innovative technique of Fourier phase contrast microscopy and multimodal optical microscopy for live cell imaging of biological samples. I will present some highlights of our work with particular reference to development of inexpensive biomedical devices.

Biography:

Sadik Guner received the B.S.degree in physics education from Middle East Technical University(METU), the M.S.degree in physics from FatihUniversity,and the Ph.D.degree in physics from GebzeTechnical University, Kocaeli,Turkey, in 1994, 1999, and 2003, respectively.He is currently a Professor of solid state physics at Fatih University,İstanbul. His research interests include magnetic materials, thermoelectric generators and thin films.

Abstract:

The pure ZnO and Cr doped ZnO (Cr:ZnO) thin films (thickness: 200 nm) were grown on both side polished silica (SiO₂) substrates by RF magnetron sputtering at room temperature. As deposited samples were annealed at 400 °C, 500°C and 600 °C for 45 min in quartz annealing furnace system, respectively. The structural and chemical composition analyses were carried out by X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectrometry (EDS). XRD studies revealed that the almost single crystalline hexagonal Wurtzite structure of pure ZnO film disappears with increasing Cr concentration and annealing process contributes the long range crystal order of films. SEM images show that average grain size is around 30 nm. EDS results indicate that only Zn, Cr and O elements are present in the Cr:ZnO thin films. The electrical properties were investigated by using the Four Point Probe (FPP) method. The smallest electrical resistivity for doped samples were obtained at 600 °C  annealing temperature and specifically as 5.34×10⁻⁴ Ω⋅cm belonging to Cr_8.21ZnO. The electrical conductivity and carrier concentration of the films are increased while mobility carriers are decreased with increasing Cr content. The optical properties were studied in the wavelength region of 200-1000 nm by employing UV-vis spectroscopy. Pure ZnO and Cr:ZnO films that include 3.22 at. % Cr content (or less), have transmittance above 70 % between 400-1000 nm before annealing.  It was observed that all annealed samples have higher average transmittance in the range of 200–1000 nm as compared to as-deposited films. Tauc plots were drawn to specify the optical energy band gap (E_g) of  as-deposited and annealed samples. The E_g increases from 3.24 eV to 3.90 eV with incrasing Cr concent from x: 0 at. % to 3.22 at. % and then decreases to 1.60 eV for 11.80 % Cr concentration.