講座題目：恒元物理學講座（第088期）：Multipartite Gaussian steering: Monogamy constraints and quantum cryptography applications
講座人:何瓊毅 研究員
講座時間：10:30
講座日期：2017-6-16
地點：長安校區(qū) 物理學與信息技術學院六層學術報告廳（致知樓3623-3624）
主辦單位：物理學與信息技術學院
講座內容：The concept of quantum steering was originally introduced bySchr?dinger to describe the “spooky action-at-a-distance” effect noted in theEinstein-Podolsky-Rosen (EPR) paradox, whereby local measurements performed onone party apparently adjust (steer) the state of another distant party. Weextend to study multipartite steering distributed over many parties. First, wederived inequalities to demonstrate multipartite EPR steering [1] which hasbeen experimentally tested with optical network up to eight modes [2]. Second,we derived laws for the distribution of quantum steering among differentparties in multipartite Gaussian states under Gaussian measurements [3]. Veryrecently, the monogamy relations for Gaussian steerability have beendemonstrated for four-mode square Gaussian cluster state [4]. Our results pindown the role of multipartite steering for quantum communication.
[1] Q. Y. He & M. D. Reid, Phys. Rev. Lett. 111, 250403 (2013).
[2] S. Armstrong et al., Nature Physics 11, 167-172 (2015).
[3] Y. Xiang et al., Phys. Rev. A 95, 010101R (2017).
[4] X. W. Deng et al., Phys. Rev. Lett. 118, 230501 (2017).
