Boston University

摘要：
The simulated annealing method for was first proposed in the context of classical spin glasses and has become one of the most successful global optimization methods. The basic idea is that a Monte Carlo simulation with slowly decreasing temperature can explore the energy (cost-function) landscape of a complex system without getting trapped in local minimums. It is then natural to consider similar schemes based on slow reduction of quantum fluctuations in quantum annealing processes. Such schemes have been explored for some time, in theoretical model studies as well as in experiments on frustrated Ising spin systems. Quantum annealing has risen to particular prominence in the context of quantum computation, where there are now serious efforts to implement the method in actual devices, such as the D-wave quantum annealer. It is not yet clear whether true quantum annealing has been realized, however. Beyond this practical issue, a fundamental question is whether quantum annealing really is more efficient than classical simulated annealing for solving important optimization problems. I will discuss recent numerical work on this issue based on non-equilibrium quantum Monte Carlo simulations in imaginary time, in which a quantum Ising spin glass is brought toward a quantum-critical point on its way to reaching the classical optimum ground state energy.
 
Reference: C.-W. Liu, A. Polkovnikov, A. W. Sandvik, arXiv:1409.7192.

报告人简介：
Anders Sandvik is a Professor of Physics at Boston University. He earned his PhD at the University of California, Santa Barbara, in 1993 and carried out postdoctoral work at Florida State University and the University of Illinois at Urbana-Champaign. He was appointed a Senior Research Fellow of the Academy of Finland in 2000 and moved to Boston University as an associate professor in 2004 (promoted to full professorship in 2008). He has held visiting research appointments at The University of Tokyo, National Taiwan University, Sun Yat-Sen University (Guangzhou, China), and the University of New South Wales (Sydney, Australia). He is a Fellow of the American Physical Society. Professor Sandvik's research is primarily focused on the quantum many-body problem. He has developed widely used quantum Monte Carlo simulation methods and applied these to challenging problems in quantum magnetism, in particular.

联系人：杨义峰（Tel: 82649448）