Inversion of moments to retrieve joint probabilities in quantum sequential measurements

Karthik, HS and Katiyar, Hemant and Shukla, Abhishek and Mahesh, TS and Devi, Usha AR and Rajagopal, AK (2013) Inversion of moments to retrieve joint probabilities in quantum sequential measurements. In: Physical Review A, 87 (5). 052118_1-052118_6.

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Abstract

A sequence of moments obtained from statistical trials encodes a classical probability distribution. However, it is well known that an incompatible set of moments arises in the quantum scenario, when correlation outcomes associated with measurements on spatially separated entangled states are considered. This feature, viz., the incompatibility of moments with a joint probability distribution, is reflected in the violation of Bell inequalities. Here, we focus on sequential measurements on a single quantum system and investigate if moments and joint probabilities are compatible with each other. By considering sequential measurement of a dichotomic dynamical observable at three different time intervals, we explicitly demonstrate that the moments and the probabilities are inconsistent with each other. Experimental results using a nuclear magnetic resonance system are reported here to corroborate these theoretical observations, viz., the incompatibility of the three-time joint probabilities with those extracted from the moment sequence when sequential measurements on a single-qubit system are considered.

Item Type:	Journal Article
Publication:	Physical Review A
Publisher:	American Physical Society
Additional Information:	Copyright of this article belongs to American Physical Society.
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	11 Jul 2013 06:27
Last Modified:	11 Jul 2013 06:27
URI:	http://eprints.iisc.ac.in/id/eprint/46821

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