Speedup in classical simulation of Gaussian boson sampling  

高斯玻色采样的经典模拟的加速

作　　者：Bujiao Wu Bin Cheng Fei Jia Jialin Zhang Man-Hong Yung Xiaoming Sun 吴步娇;程斌;贾飞;张家琳;翁文康;孙晓明(Institute of Computing Technology,Chinese Academy of Sciences,Beijing 100190,China;University of Chinese Academy of Sciences,Beijing 100049,China;Institute for Quantum Science and Engineering,Department of Physics,Southern University of Science and Technology,Shenzhen 518055,China;Shenzhen Key Laboratory of Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China;Central Research Institute,Huawei Technologies,Shenzhen 518129,China;CAS Center of Excellence in Topological Quantum Computation,Beijing 100190,China)

机构地区：[1]Institute of Computing Technology,Chinese Academy of Sciences,Beijing 100190,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Institute for Quantum Science and Engineering,Department of Physics,Southern University of Science and Technology,Shenzhen 518055,China [4]Shenzhen Key Laboratory of Quantum Science and Engineering,Southern University of Science and Technology,Shenzhen 518055,China [5]Central Research Institute,Huawei Technologies,Shenzhen 518129,China [6]CAS Center of Excellence in Topological Quantum Computation,Beijing 100190,China

出　　处：《Science Bulletin》2020年第10期832-841,M0004,共11页科学通报（英文版）

基　　金：supported by the Guangdong Innovative and Entrepreneurial Research Team Program (2016ZT06D348);Natural Science Foundation of Guangdong Province (2017B030308003);the Key R&D Program of Guangdong Province (2018B030326001);the Science, Technology and Innovation Commission of Shenzhen Municipality (JCYJ20170412152620376, JCYJ20170817105046702 and KYTDPT20181011104202253);the National Natural Science Foundation of China (11875160 and U1801661);supported by the National Natural Science Foundation of China (61832003, 61872334);the Economy, Trade and Information Commission of Shenzhen Municipality (201901161512);the Strategic Priority Research Program of Chinese Academy of Sciences (XDB28000000);K. C. Wong Education Foundation

摘　　要：Gaussian boson sampling is an alternative model for demonstrating quantum computational supremacy,where squeezed states are injected into every input mode, instead of applying single photons as in the case of standard boson sampling. Here by analyzing numerically the computational costs, we establish a lower bound for achieving quantum computational supremacy for a class of Gaussian bosonsampling problems. Specifically, we propose a more efficient method for calculating the transition probabilities, leading to a significant reduction of the simulation costs. Particularly, our numerical results indicate that one can simulate up to 18 photons for Gaussian boson sampling at the output subspace on a normal laptop, 20 photons on a commercial workstation with 256 cores, and about 30 photons for supercomputers. These numbers are significantly smaller than those in standard boson sampling, suggesting that Gaussian boson sampling could be experimentally-friendly for demonstrating quantum computational supremacy.量子霸权是近年来量子计算中备受关注的一个课题.它描述的是,对于某些特定问题,量子计算能有效解决;但当问题规模超过某个值时,任何经典计算机都无法有效模拟.玻色采样就是这些特定问题中的一个.但玻色采样所需要的单光子源在实验上很难大规模实现,因此人们考虑问题的一个变种--高斯玻色采样.本文通过数值模拟给出了高斯玻色采样实现量子霸权的下界,并且提出了一个更高效的计算采样概率的方法,大大减少了模拟采样所需的代价.在笔记本上执行该算法最多可以模拟18个光子的高斯玻色采样问题;使用256核的商业工作站可以模拟20个光子的采样;基于这些数据,可以预测超级计算机最多能模拟30个光子的采样.这些数字比标准玻色采样的数值模拟结果小,说明高斯玻色采样的经典模拟更加困难;加上其在实验上更容易实现,因此作为量子霸权的候选项更有优势.

关 键 词：Gaussian boson sampling Classical simulation Hafnian Probability distribution Marginal distribution Quantum optics 

分 类 号：TP38[自动化与计算机技术—计算机系统结构] O413[自动化与计算机技术—计算机科学与技术]