Quantum states as observables: Their variance and nonclassicality

doi:10.1103/PhysRevA.102.062211

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	Quantum states as observables: Their variance and nonclassicality
	Zhang, Yue 1,4; Luo, Shunlong 2,3
刊名	PHYSICAL REVIEW A
	2020-12-17
卷号	102 期号:6 页码:6
ISSN号	2469-9926
DOI	10.1103/PhysRevA.102.062211
英文摘要	Two basic ingredients in the quantum formalism are the concepts of states and observables, and apart from the average value (which includes the Born probability as a paramountly important case), the variance is the most fundamental and prominent quantity arising from the coupling of a state and an observable. Given the simplicity and ubiquity of the variance, it seems surprising that we can still exploit the variance to gain conceptually different insight into the quantum substratum. The purpose of the present work is to advocate the following idea: By inputting a general quantum state as the observable in the variance and incorporating a resolution of identity induced by coherent states, we obtain a mathematically simple and physically intuitive method for quantifying nonclassicality. We reveal its fundamental properties and highlight its connection with phase-space quantification of nonclassicality. The idea further suggests a whole family of appealing quantifiers of nonclassicality involving deep mathematical subtlety and an intriguing conjecture with physical significance. Some prototypical examples are worked out to illustrate the concept. This approach of regarding states as observables presents an opportunity for investigating quantum features from an alternative perspective of uncertainty.
资助项目	National Natural Science Foundation of China[11875317] ; National Center for Mathematics and Interdisciplinary Sciences, CAS[Y029152K51]
WOS研究方向	Optics ; Physics
语种	英语
出版者	AMER PHYSICAL SOC
WOS记录号	WOS:000600558000001
内容类型	期刊论文
源URL	[http://ir.amss.ac.cn/handle/2S8OKBNM/57837]
专题	应用数学研究所
通讯作者	Luo, Shunlong
作者单位	1.Peking Univ, Frontiers Sci Ctr Nanooptoelect, Sch Phys, State Key Lab Mesoscop Phys, Beijing 100871, Peoples R China 2.Univ Chinese Acad Sci, Sch Math Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Acad Math & Syst Sci, Beijing 100190, Peoples R China 4.Beijing Acad Quantum Informat Sci, Beijing 100193, Peoples R China
推荐引用方式 GB/T 7714	Zhang, Yue,Luo, Shunlong. Quantum states as observables: Their variance and nonclassicality[J]. PHYSICAL REVIEW A,2020,102(6):6.
APA	Zhang, Yue,&Luo, Shunlong.(2020).Quantum states as observables: Their variance and nonclassicality.PHYSICAL REVIEW A,102(6),6.
MLA	Zhang, Yue,et al."Quantum states as observables: Their variance and nonclassicality".PHYSICAL REVIEW A 102.6(2020):6.