Thermodynamics and the structure of quantum theory

Despite its enormous empirical success, the formalism of quantum theory still raises fundamental questions: why is nature described in terms of complex Hilbert spaces, and what modifications of it could we reasonably expect to find in some regimes of physics? Here we address these questions by study...

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Hauptverfasser: Krumm, Marius (VerfasserIn) , Müller, Markus P. (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 19 April 2017
In: New journal of physics
Year: 2017, Jahrgang: 19, Heft: 4
ISSN:1367-2630
DOI:10.1088/1367-2630/aa68ef
Online-Zugang:Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1088/1367-2630/aa68ef
Verlag, kostenfrei, Volltext: http://stacks.iop.org/1367-2630/19/i=4/a=043025
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Verfasserangaben:Marius Krumm, Howard Barnum, Jonathan Barrett and Markus P. Müller
Beschreibung
Zusammenfassung:Despite its enormous empirical success, the formalism of quantum theory still raises fundamental questions: why is nature described in terms of complex Hilbert spaces, and what modifications of it could we reasonably expect to find in some regimes of physics? Here we address these questions by studying how compatibility with thermodynamics constrains the structure of quantum theory. We employ two postulates that any probabilistic theory with reasonable thermodynamic behaviour should arguably satisfy. In the framework of generalised probabilistic theories, we show that these postulates already imply important aspects of quantum theory, like self-duality and analogues of projective measurements, subspaces and eigenvalues. However, they may still admit a class of theories beyond quantum mechanics. Using a thought experiment by von Neumann, we show that these theories admit a consistent thermodynamic notion of entropy, and prove that the second law holds for projective measurements and mixing procedures. Furthermore, we study additional entropy-like quantities based on measurement probabilities and convex decomposition probabilities, and uncover a relation between one of these quantities and Sorkin’s notion of higher-order interference.
Beschreibung:Gesehen am 16.10.2018
Beschreibung:Online Resource
ISSN:1367-2630
DOI:10.1088/1367-2630/aa68ef