Three statistical descriptions of classical systems and their extensions to hybrid quantum–classical systems

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Authors

  • Andrés Darío Bermúdez Manjarres
  • Marcel Reginatto
  • Sebastian Ulbricht

External Research Organisations

  • Universidad Distrital Francisco Jose de Caldas
  • Physikalisch-Technische Bundesanstalt PTB
  • Technische Universität Braunschweig
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Details

Original languageEnglish
Article number780
JournalEuropean Physical Journal Plus
Volume139
Issue number9
Publication statusPublished - 2 Sept 2024
Externally publishedYes

Abstract

We present three statistical descriptions for systems of classical particles and consider their extension to hybrid quantum–classical systems. The classical descriptions are ensembles on configuration space, ensembles on phase space, and a Hilbert space approach using van Hove operators which provides an alternative to the Koopman–von Neumann formulation. In all cases, there is a natural way to define classical observables and a corresponding Lie algebra that is isomorphic to the usual Poisson algebra in phase space. We show that in the case of classical particles the three descriptions are equivalent and indicate how they are related. We then modify and extend these descriptions to introduce hybrid models where a classical particle interacts with a quantum particle. The approach of ensembles on phase space and the Hilbert space approach, which are novel, lead to equivalent hybrid models, while they are not equivalent to the hybrid model of the approach of ensembles on configuration space. Thus, we end up identifying two inequivalent types of hybrid systems, making different predictions, especially when it comes to entanglement. These results are of interest regarding “no-go” theorems about quantum systems interacting via a classical mediator which address the issue of whether gravity must be quantized. Such theorems typically require assumptions that make them model dependent. The hybrid systems that we discuss provide concrete examples of inequivalent models that can be used to compute simple examples to test the assumptions of the “no-go” theorems and their applicability.

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Cite this

Three statistical descriptions of classical systems and their extensions to hybrid quantum–classical systems. / Bermúdez Manjarres, Andrés Darío; Reginatto, Marcel; Ulbricht, Sebastian.
In: European Physical Journal Plus, Vol. 139, No. 9, 780, 02.09.2024.

Research output: Contribution to journalArticleResearchpeer review

Bermúdez Manjarres AD, Reginatto M, Ulbricht S. Three statistical descriptions of classical systems and their extensions to hybrid quantum–classical systems. European Physical Journal Plus. 2024 Sept 2;139(9):780. doi: 10.1140/epjp/s13360-024-05452-0
Bermúdez Manjarres, Andrés Darío ; Reginatto, Marcel ; Ulbricht, Sebastian. / Three statistical descriptions of classical systems and their extensions to hybrid quantum–classical systems. In: European Physical Journal Plus. 2024 ; Vol. 139, No. 9.
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