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物理学科学术报告(New York University, Tim Byrnes和Daniel Stein 教授)
发布时间: 2019-05-05 浏览次数: 171


报告题目一】Nature vs. Nurture in Complex (and Not-So-Complex) Systems

【报告人】Daniel Stein 教授,New York University

【时间】510日(星期五)上午 09: 00-10:00

【地点】29#-414

Understanding the dynamical behavior of many-particle systems following a deep quench is a central issue in both statistical mechanics and complex systems theory. One of the basic questions centers on the issue of predictability: given a system with a random initial state evolving through a well-defined stochastic dynamics, how much of the information contained in the state at future times depends on the initial condition (``nature'') and how much on the dynamical realization (``nurture'')? We discuss this question and present both old and new results for both homogeneous and random systems in low and high dimension.

【作者简介Daniel L. Stein is Professor of Physics and Mathematics at New York University. From 2006-2012 he served as NYU Dean of Science.  Prior to coming to NYU, he served on the faculties at Princeton University and at the University of Arizona, where he was Head of the Department of Physics for a decade. He received his Ph.D. In Physics from Princeton University in 1979.

His research is in the fields of theoretical condensed matter physics, statistical mechanics, and biological physics.  It focuses primarily on randomness and disorder in condensed matter systems, with an emphasis on magnetic materials and on stochastic processes leading to rare nucleation events.  In addition, he has worked on topics as diverse as protein biophysics, biological evolution, amorphous semiconductors, superconductors and superfluids, liquid crystals, neutron stars, and the interface between particle physics and cosmology.

His awards include a Princeton University C.E. Proctor Fellowship, an Alfred P. Sloan Fellowship, University of Arizona College of Science Distinguished Teaching Award, Commission on the Status of Women Vision 2000 Award, election as a Fellow of the American Physical Society, election as a Fellow of the American Association for the Advancement of Science, the U.S. Air Force Exemplary Civilian Service Medal, and a John Simon Guggenheim Foundation Fellows.


报告题目二】Quantum clock synchronization without synchronized clocks

【报告人】Tim Byrnes 教授,NYU Shanghai

【时间】510日(星期五)上午 10: 00-11:00

【地点】29#-414

A  major outstanding problem for many quantum clock synchronization   protocols is the hidden assumption of a common phase reference between   the parties to be synchronized. In general, the definition of the   quantum states between two parties do not have consistent phase   definitions, which can lead to an unknown systematic error. We show  that  despite prior arguments to the contrary, it is possible to remove  this  unknown phase via entanglement purification. This closes the  loophole  for entanglement based quantum clock synchronization  protocols, which is  a non-local approach to synchronize two clocks  independent of the  properties of the intervening medium. Starting with  noisy Bell pairs, we  show that the scheme produces a singlet state for  any combination of  (i) differing basis conventions for Alice and Bob;  (ii) an overall time  offset in the execution of the purification  algorithm; and (iii) the  presence of a noisy channel. Error estimates  reveal that better  performance than existing classical Einstein  synchronization protocols  should be achievable using current  technology.

References

[1] Ebubechukwu O. Ilo-Okeke, Louis Tessler, Jonathan P. Dowling and Tim Byrnes, npj Quantum Information  4, 40 (2018).

[2]  R. Jozsa, D. S. Abrams, J. P. Dowling, and C. P. Williams, Phys. Rev. Lett. 85, 2010 (2000).

【作者简介Tim  Byrnes is Assistant Professor of Physics at NYU Shanghai. He is also   Visiting Assistant Professor at the National Institute of Informatics   in Tokyo, Japan. He holds a PhD from the University of New South Wales   in Sydney, Australia.

Professor Byrnes' research  interests are  in quantum information technologies, condensed matter  physics, and AMO  (atomic, molecular, optical) physics. Specifically, he  is interested in  various applications of Bose-Einstein condensates to  quantum  information. He is also interested in the interface of physics  and  biology and emergent phenomena.

Tim Byrnes completed his  Ph.D.  at the University of New South Wales in Sydney, Australia in the  fields  of condensed matter physics and high energy physics under the   supervision of Prof. Chris Hamer.  During this time he worked on   applications of DMRG (Density Matrix Renomalization Group), a powerful   method for solving 1D quantum many-body problems, to lattice gauge   theories.  He then moved to Tokyo, Japan to commence a postdoctoral   fellowship with Prof. Yoshihisa Yamamoto in the field of quantum   information at the National Institute of Informatics and the University   of Tokyo.  There he worked on topics related to quantum simulation,  such  as methods of solving lattice gauge theories on a quantum  computer, and  semiconductor implementations of a quantum simulator.  He  has worked on  the theory of Bose-Einstein condensation in  exciton-polariton systems,  such as the BEC-BCS crossover and  applications to the generation of  non-classical light.

He is now  Assistant Professor at NYU  Shanghai, where he examines Bose-Einstein  condensates for various  applications in quantum information technology.

【邀请人】李慧军, 高先龙

欢迎各位老师和同学参加.