Inequivalent Leggett-Garg inequalities. (1st August 2017)

• Record Type: Journal Article
• Authors: Kumari, Swati; Pan, A. K.
• Is Part Of: Europhysics letters. Volume 118:Number 5(2017:Jun.)
• Publication Date: 2017-08-01
• Subjects: 03.65.Ta -- 03.67.-a; Physics -- Periodicals; Electronic journals; 530.05
• DOI: 10.1209/0295-5075/118/50002
• Languages: English
• ISSNs: 0295-5075

Abstract

Abstract: It remains an open question how a realist view of the macroscopic world emerges from a quantum formalism. For testing the macrorealism in the quantum domain, an interesting approach was put forward by Leggett and Garg in 1985, by formulating a suitable inequality valid for any macrorealistic theory. Recently, by following the Wigner idea of local realist inequality, a probabilistic version of standard Leggett-Garg inequalities has also been proposed. While the Wigner form of local realist inequalities is equivalent to the two-party, two-measurements and two-outcomes CHSH inequalities, in this paper we provide a generic proof to demonstrate that the Wigner form of Leggett-Garg inequalities is not only inequivalent to the standard ones, but also stronger than the latter. This is demonstrated by quantifying the amount of disturbance caused by a priori measurement to the subsequent measurements. In this connection, the relation between LGIs and another formulation of macrorealism known as no-signaling in time is examined.