Title:	Quantum which-way information and fringe visibility when the detector is entangled with an ancilla
Authors:	Tej, Prabhu J. Usha Devi, A.R. Karthik, H.S. Sudha Rajagopal, A.K.
Issue Date:	Jun-2014
Publisher:	American Physical Society
Citation:	Physical Review A, 2014, Vol. 89, p062116
Abstract:	Quantum-mechanical wave-particle duality is quantified in terms of a trade-off relation between the fringe visibility and the which-way distinguishability in an interference experiment. This relation was recently generalized by Banaszek et al. [Nat. Commun. 4, 2594 (2013)] when the particle is equipped with an internal degree of freedom such as spin. Here, we extend the visibility-distinguishability trade-off relation to quantum interference of a particle possessing an internal degree of freedom, when the which-way detector state is entangled with an ancillary system. We introduce an extended which-way distinguishability DE and the associated extended fringe visibility VE, satisfying the inequality D2E+V2E≤1 in this scenario. We illustrate, with the help of three specific examples, that while the which-way information inferred solely from the detector state (without ancilla) vanishes, the extended distinguishability retrievable via measurements on the detector-ancilla entangled state is nonzero. Furthermore, in all the three examples, the extended visibility and the generalized visibility (which was introduced by Banaszek et al.) match identically with each other.
Description:	Open Access
URI:	http://hdl.handle.net/2289/5974
ISSN:	1094-1622 (Online) 1050-2947
Alternative Location:	http://arxiv.org/abs/1404.6065 http://dx.doi.org/10.1103/PhysRevA.89.062116
Copyright:	2014 American Physical Society This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Physical Society
Appears in Collections:	Research Papers (LAMP)

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