https://doi.org/10.1140/epjc/s10052-023-11186-7
Regular Article - Theoretical Physics
Scalar field as a perfect fluid: thermodynamics of minimally coupled scalars and Einstein frame scalar-tensor gravity
1
Department of Physics and Astronomy, Bishop’s University, 2600 College Street, J1M 1Z7, Sherbrooke, QC, Canada
2
Max Planck Institute for Gravitational Physics (Albert Einstein Institute), Callinstraße 38, 30167, Hannover, Germany
3
Institute for Theoretical Physics, Heidelberg University, Philosophenweg 16, 69120, Heidelberg, Germany
4
Institute for Theoretical Physics, ETH Zurich, Wolfgang-Pauli-Strasse 27, 8093, Zurich, Switzerland
Received:
22
October
2022
Accepted:
29
December
2022
Published online:
16
January
2023
We revisit the analogy between a minimally coupled scalar field in general relativity and a perfect fluid, correcting previous identifications of effective temperature and chemical potential. This provides a useful complementary picture for the first-order thermodynamics of scalar-tensor gravity, paving the way for the Einstein frame formulation (which eluded previous attempts) and raises interesting questions to further develop the analogy.
© The Author(s) 2023
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