Markov chain Monte Carlo methods for graph refinement in spinfoam cosmology

We study the behavior of the Lorentzian Engle-Pereira-Rovelli-Livine spinfoam amplitude with homogeneous boundary data, under a graph refinement going from five to twenty boundary tetrahedra. This can be interpreted as a wave function of the Universe, for which we compute boundary geometrical operat...

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Hauptverfasser: Frisoni, Pietropaolo (VerfasserIn) , Gozzini, Francesco (VerfasserIn) , Vidotto, Francesca (VerfasserIn)
Dokumenttyp: Article (Journal)
Sprache:Englisch
Veröffentlicht: 14 April 2023
In: Classical and quantum gravity
Year: 2023, Jahrgang: 40, Heft: 10, Pages: 1-32
ISSN:1361-6382
DOI:10.1088/1361-6382/acc5d6
Online-Zugang:Verlag, lizenzpflichtig, Volltext: https://doi.org/10.1088/1361-6382/acc5d6
Verlag, lizenzpflichtig, Volltext: https://dx.doi.org/10.1088/1361-6382/acc5d6
Volltext
Verfasserangaben:Pietropaolo Frisoni, Francesco Gozzini and Francesca Vidotto
Beschreibung
Zusammenfassung:We study the behavior of the Lorentzian Engle-Pereira-Rovelli-Livine spinfoam amplitude with homogeneous boundary data, under a graph refinement going from five to twenty boundary tetrahedra. This can be interpreted as a wave function of the Universe, for which we compute boundary geometrical operators, correlation functions, and entanglement entropy. The numerical calculation is made possible by adapting the Metropolis-Hastings algorithm, along with recently developed computational methods appropriate for the deep quantum regime. We confirm that the transition amplitudes are stable against such refinement. We find that the average boundary geometry does not change, but the new degrees of freedom correct the quantum fluctuations of the boundary and the correlations between spatial patches. The expectation values are compatible with their geometrical interpretation and the correlations between neighboring patches decay when computed across different spinfoam vertices.
Beschreibung:Gesehen am 21.09.2023
Beschreibung:Online Resource
ISSN:1361-6382
DOI:10.1088/1361-6382/acc5d6