题 目：Quasiprobability representations of quantum mechanics with minimal negativity 

报告人：朱黄俊博士(Institute for Theoretical Physics, University of Cologne)
时 间：11月24日（周四），上午10:00-11:00
地 点：第一实验楼423会议室

Abstract：Quasiprobability representations, such as the Wigner function, play an important role in various research areas, such as quantum optics and quantum computation. The inevitable appearance of negativity in such representations is often regarded as a signature of nonclassicality, which has profound implications for quantum computation. However, little is known about the minimal negativity that is necessary in general quasiprobability representations. In this work I present an overview of quasiprobability representations for finite dimensional quantum systems and initiate a systematic study of the degree of negativity in these representations. I show that those representations with minimal negativity are in one-to-one correspondence with the elusive symmetric informationally complete measurements. In addition, most of them are automatically covariant with respect to the Heisenberg-Weyl groups. An interesting tradeoff between negativity and symmetry in quasiprobability representations is also revealed In the course of study. This work offers valuable insight on the distinction between quantum theory and classical probability theory in terms of negativity. Besides the foundational significance, it may have an impact on the current study on the theoretical foundations of quantum computation.

Reference: PRL 117, 120404 (2016)

Short Bio：朱黄俊博士在新加坡国立大学量子技术中心取得博士并先后在加拿大圆周理论物理研究所和德国科隆理论物理研究所从事量子信息理论研究。特别在量子测量，量子态层析，非局域关联，准概率表示，量子力学基本问题等领域取得了突出成绩，在包括PRL在内的国际知名期刊发表论文20多篇。最近一年在物理学权威期刊PRL发表论文3篇，其中两篇为独立作者。同时还应邀在各种研讨会，世界名校以及著名研究机构做报告十几次。