How to effectively certify genuine quantum properties of a physical system consisting of hundreds of qubits? What quantum property is responsible for the quantum speed-up? Even as we enter the era of rapidly developing quantum technologies, these questions can not be adequately answered. We employ a new approach, inspired by the fable “Blind men and an elephant”, in which local information is used to explore the classical/quantum boundary. Starting from a classical problem in mathematical physics, the marginal problem, we characterize near-neighbor classical correlations of infinite translation-invariant probability distributions in 1- and 2-dimensions. We then compute Bell inequalities from these correlations and study their violations by using tools from quantum many-body physics and condensed matter theory such as Matrix Product States and Tensor Network States. These classical and quantum problems will provide us new tools to answer the questions above by allowing us to study global entanglement, nonlocality and the quantum speed-up by only using physically accessible local information.
Speaker's Brief Introduction：
王子竹，国家青年特聘专家，教授，博士生导师，现就职于成都电子科技大学基础与前沿研究院。
本科及硕士毕业于法国格勒诺布尔约瑟夫傅立叶大学信息科学与应用数学学院，博士毕业于法国巴黎高科电信学院。虽出身计算机科学，却长期致力于物理问题，尤其是量子理论中的基础问题的研究。
主要研究方向为多体量子系统的基本性质，例如纠缠与非定域，的判断与表征。由于多体量子系统需要复杂的数学表述，从中提取任何有用的信息都需要借助现代的计算机数值代数与最优化算法以及物理上的对称假设。
主要研究成果为交换对称以及一维无限平移对称的量子态的纠缠与非定域特性，并在研究过程中对凝聚态物理与最优化理论中的数值方法有不少的借鉴与补充。与此同时，从计算机科学中最早的计算模型之一：细胞自动机出发，研究了基于因果律的经典与量子计算模型，并将细胞自动机的概念推广到图论中，使其能够在当今量子基础理论的研究热点之一：因果网络当中占据一席之地。