报告题目：Einstein-Podolsky-Rosen experiment with two spatially separated Bose-Einstein condensates

报告人: 李奕璠,瑞士巴塞尔大学

报告时间: 2023年05月08日16:00

报告地点: 理科楼C302

报告摘要：In 1935, Einstein, Podolsky, and Rosen (EPR) considered an hypothetical experiment, in which measurements are performed on two spatially separated quantum systems in an entangled state. The entanglement results in strong correlations between the measurement outcomes, making it possible to predict complementary properties of one system based on measurements of the other, with an uncertainty product below the Heisenberg bound. This “EPR paradox” revealed a conflict between quantum mechanics and a local realist description of the world. Since then experiment realisation has been realized with small quantum systems, while a demonstration of the EPR paradox with massive many-particle systems has so far remained elusive.

I will present our experiment demonstrating EPR paradox with two spatially separated many-particle systems. Our experiments are based on a pseudo spin-1/2 Bose Einstein condensate (BEC) of Rubidium-87 on an atom chip. Following the scenario considered by EPR, we first entangle about 1400 atoms in a single condensate by engineering the interatomic interactions. Subsequently, we split this entangled many-particle system into two halves and separate them spatially. Our technique allows us to individually address the collective spins of the two BECs, thereby realizing arbitrary spin measurements on the two systems. We observe strong correlations between the split systems, allowing us to infer measurement results of non-commuting spin observables in one system from measurements on the other, demonstrating the paradoxical situation envisioned by EPR.

Our results show that the conflict between quantum mechanics and local realism does not disappear as the system size is increased to over a thousand massive particles. Besides the interest in understanding fundamental aspects of entanglement of many-body systems, our experiments enable new investigations in quantum-enhanced metrology using spatially split probes.

报告人简介：李奕璠，2012-2016年本科毕业于清华大学工程物理系，2016年-2021博士就读于清华大学，方向为冷原子实验与量子精密测量。2021年至今于瑞士巴塞尔大学从事博士后研究，内容为：利用原子芯片上的旋量玻色爱因斯坦凝聚体，进行多粒子纠缠态的制备与探测。