报告题目

Simulating quantum Schrödinger cats in ion-traps

报 告 人

Prof. P. D. Drummond, 　Centre for Atom Optics and Ultrafast Spectroscopy Swinburne University of Technology, Australia

报告地点

物理楼南506

报告时间

2013年6月3日下午1:30-3:00

联 系 人

何琼毅（59367）

报告摘要

How can we simulate the quantum Schrödinger cat? To prove it hasquantum properties, we would like to demonstrate a macroscopic Bell violation, in a macroscopic superposition experiment as in an ion trap. Direct calculation of macroscopic superposition of ions involves astronomically large Hilbert spaces. Can we use random sampling to overcome this complexity?

The answer is to follow the example of French impressionist Georges Seurat. The quantum state can be represented tomographically as a random assembly of coherent ‘pixels’, each giving part of the story, just like a pointillist painting. We calculate scaling properties of SU(2) Q-function sampling for up to 60 ions in a Mermin-GHZ Schrodinger Cat' state. This is an extension to a much larger size than the remarkable ion trap experiments of last year's Nobel Laureate, Dave Wineland.We show that random sampling methods are indeed able to represent a Bell violation, using GPU supercomputers for increased speed.

Surprisingly, we show that the random sampling method using SU(2) coherent state phase-space is exponentially FASTER than experiment, which is the opposite to the usual expected behavior for quantum simulations.