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Title

Linear entropy in quantum phase space

Author(s)

Rosales-Zarate, Laura E. C.;  Drummond, P. D.

Abstract

We calculate the quantum Renyi entropy in a phase-space representation for either fermions or bosons. This can also be used to calculate purity and fidelity, or the entanglement between two systems. We show that it is possible to calculate the entropy from sampled phase-space distributions in normally ordered representations, although this is not possible for all quantum states. We give an example of the use of this method in an exactly soluble thermal case. The quantum entropy cannot be calculated at all using sampling methods in classical symmetric (Wigner) or antinormally ordered (Husimi) phase spaces, due to inner-product divergences. The preferred method is to use generalized Gaussian phase-space methods, which utilize a distribution over stochastic Green's functions. We illustrate this approach by calculating the reduced entropy and entanglement of bosonic or fermionic modes coupled to a time-evolving, non-Markovian reservoir.

Publication type

Journal article

Research centre

Swinburne University of Technology. Faculty of Engineering and Industrial Sciences. Centre for Atom Optics and Ultrafast Spectroscopy

Source

Physical Review A: Atomic, Molecular, and Optical Physics, Vol. 84, no. 4 (Oct 2011), article no. 042114

Publication year

2011

FOR Code(s)

01 Mathematical Sciences;  02 Physical Sciences;  03 Chemical Sciences

Keyword(s)

Gaussian operators;  Phase-space representations;  Quantum entropy

Publisher

American Physical Society

ISSN

1050-2947

Publisher URL

http://dx.doi.org/10.1103/PhysRevA.84.042114

Copyright

Copyright © 2011 American Physical Society. The published version of the paper is reproduced here with the kind permission of the publisher.

Full text

Peer reviewed