On the observation of nonclassical excitations in Bose–Einstein condensates

Finke, Andreas and Jain, Piyush and Weinfurtner, Silke (2016) On the observation of nonclassical excitations in Bose–Einstein condensates. New Journal of Physics, 18 (113017). pp. 1-14. ISSN 1367-2630

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Abstract

In the recent experimental and theoretical literature well-established nonclassicality criteria from the field of quantum optics have been directly applied to the case of excitations in matter-waves. Among these are violations of Cauchy–Schwarz inequalities, Glauber–Sudarshan P-nonclassicality, subPoissonian number-difference squeezing (also known as the two-mode variance) and the criterion of nonseparability. We review the strong connection of these criteria and their meaning in quantum optics, and point out differences in the interpretation between light and matter waves. We then calculate observables for a homogeneous Bose–Einstein condensate undergoing an arbitrary modulation in the interaction parameter at finite initial temperature, within both the quantum theory as well as a classical reference. We conclude that to date in experiments relevant for this scenario nonclassical effects have not conclusively been observed and conjecture that additional, noncommuting, observables have to be measured to this end. Moreover this has important implications for proposed analog gravity models where the observation of nonclassical effects is a major goal.

Item Type: Article
Keywords: nonclassicality, analogue gravity, Bose–Einstein condensates, Bogoliubov theory, Gross-Pitaevskii equation, parametric resonance, quantum correlations
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Mathematical Sciences
University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Identification Number: https://doi.org/10.1088/1367-2630/18/11/113017
Depositing User: Eprints, Support
Date Deposited: 27 Feb 2017 10:39
Last Modified: 27 Feb 2017 17:09
URI: http://eprints.nottingham.ac.uk/id/eprint/40858

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