The Gaussian entropy of fermionic systems

We consider the entropy and decoherence in fermionic quantum systems. By making a Gaussian Ansatz for the density operator of a collection of fermions we study statistical 2-point correlators and express the entropy of a system fermion in terms of these correlators. In a simple case when a set of N...

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Hauptverfasser: Prokopec, Tomislav (VerfasserIn) , Schmidt, Michael G. (VerfasserIn) , Weenink, Jan (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 18 September 2012
In: Annals of physics
Year: 2012, Jahrgang: 327, Heft: 12, Pages: 3138-3169
DOI:10.1016/j.aop.2012.09.003
Online-Zugang:Verlag, Volltext: http://dx.doi.org/10.1016/j.aop.2012.09.003
Verlag, Volltext: http://www.sciencedirect.com/science/article/pii/S0003491612001467
Volltext
Verfasserangaben:Tomislav Prokopec, Michael G. Schmidt, Jan Weenink
Beschreibung
Zusammenfassung:We consider the entropy and decoherence in fermionic quantum systems. By making a Gaussian Ansatz for the density operator of a collection of fermions we study statistical 2-point correlators and express the entropy of a system fermion in terms of these correlators. In a simple case when a set of N thermalised environmental fermionic oscillators interacts bi-linearly with the system fermion we can study its time dependent entropy, which also represents a quantitative measure for decoherence and classicalization. We then consider a relativistic fermionic quantum field theory and take a mass mixing term as a simple model for the Yukawa interaction. It turns out that even in this Gaussian approximation, the fermionic system decoheres quite effectively, such that in a large coupling and high temperature regime the system field approaches the temperature of the environmental fields.
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Beschreibung:Online Resource
DOI:10.1016/j.aop.2012.09.003