Renormalized thermal entropy in field theory

Sergio L. Cacciatori, Fabio Costa, and Federico Piazza
Phys. Rev. D 79, 025006 – Published 15 January 2009

Abstract

Standard entropy calculations in quantum field theory, when applied to a subsystem of definite volume, exhibit area-dependent UV divergences that make a thermodynamic interpretation troublesome. In this paper we define a renormalized entropy which is related with the Newton-Wigner position operator. Accordingly, whenever we trace over a region of space, we trace away degrees of freedom that are localized according to Newton-Wigner localization but not in the usual sense. We consider a free scalar field in d+1 spacetime dimensions prepared in a thermal state and we show that our entropy is free of divergences and has a perfectly sound thermodynamic behavior. In the high temperature/big volume limit our results agree with the standard QFT calculations once the divergent contributions are subtracted from the latter. In the limit of low temperature/small volume the entropy goes to zero but with a different dependence on the temperature.

  • Received 6 October 2008

DOI:https://doi.org/10.1103/PhysRevD.79.025006

©2009 American Physical Society

Authors & Affiliations

Sergio L. Cacciatori*

  • Dipartimento di Scienze Fisiche e Matematiche, Università dell’Insubria, Via Valleggio 11, I-22100 Como, Italia

Fabio Costa

  • Institut für Quantenoptik und Quanteninformation (IQOQI), Österreichische Akademie der Wissenschaften, Boltzmanngasse 3, A-1090 Wien, Austria

Federico Piazza

  • Perimeter Institute for Theoretical Physics, Waterloo, Ontario, N2L 2Y5, Canada

  • *sergio.cacciatori@uninsubria.it
  • fabio.costa@univie.ac.at
  • fpiazza@perimeterinstitute.ca

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand
Issue

Vol. 79, Iss. 2 — 15 January 2009

Reuse & Permissions
Access Options
Author publication services for translation and copyediting assistance advertisement

Authorization Required


×
×

Images

×

Sign up to receive regular email alerts from Physical Review D

Log In

Cancel
×

Search


Article Lookup

Paste a citation or DOI

Enter a citation
×