日内瓦大学博士后蔡宇报告

来源:信息科学与技术学院  作者:罗明星  日期:2021-03-15  点击数:372

报告题目:Absolutely entangled set

报告人:日内瓦大学博士后蔡宇报告

报告时间:2021318日(星期四)下午5:00

报告地点:腾讯会议(ID558 506 761

https://meeting.tencent.com/s/rWzX4ld15XCT

主持人:罗明星教授

 

 

 

摘要:通常的纠缠都是相对于固定的子系统划分而言的。全域的酉变换(global unitary)总可以把纠缠态变换到可分态上。但当我们考虑一组态的时候,情况就不一样了。在这个报告里我们引入量子态的绝对纠缠集合absolutely entangled set)的概念:对于任意的全域酉变换,集合里至少有一个态仍然是纠缠的。也就是说,对于任意的子系统划分,这个集合里都包含纠缠。我们演示在C2C2空间里最小的绝对纠缠集合的例子。此外,我们还提出了一个绝对纠缠的度量。利用多项式优化,我们得到一个酉限制下的凸优化方法,用以计算绝对纠缠的下界。[arXiv:2006.07165]

 

Abstract: The notion of entanglement of quantum states is usually defined with respect to a fixed bipartition. Indeed, a global basis change can always map an entangled state to a separable one. The situation is however different when considering a set of states. In this talk we introduce the notion of an "absolutely entangled set" of quantum states: for any possible choice of global basis, at least one of the states in the set is entangled. Hence, for all bipartitions, i.e. any possible definition of the subsystems, the set features entanglement. We present a minimum example of this phenomenon, with a set of four states in C2C2. Moreover, we propose a quantitative measure for absolute set entanglement. To lower-bound this quantity, we develop a method based on polynomial optimization to perform convex optimization over unitaries, which is of independent interest.

 

 

报告人:蔡宇,博士毕业于新加坡国立大学,导师Valerio Scarani。之后在新加坡国立大学担任博士后,现于日内瓦大学Nicolas Brunner的小组担任博士后,在PRL, Nature Comm等刊物上发表多篇论文。目前主要研究的方向是量子关联,非定域性和量子器件的认证等。

 

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