Scalar field as a perfect fluid: thermodynamics of minimally coupled scalars and Einstein frame scalar-tensor gravity

Abstract

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.

19 pages, latex

References in corpus (21)

• Dark energy cosmology: the equivalent description via different theoretical models and cosmography tests
• Imperfect Dark Energy from Kinetic Gravity Braiding
• Generalized Second Law of Thermodynamics in Quintom Dominated Universe
• Dark Energy with Phantom Crossing and the $H_0$ tension
• Theory of gravitation theories: a no-progress report
• Imperfect Dark Matter
• A note on the equivalence of a barotropic perfect fluid with a K-essence scalar field
• Consistent perturbations in an imperfect fluid
• Thermodynamical properties of dark energy
• First-order thermodynamics of Horndeski gravity
• Thermodynamics of scalar-tensor gravity
• A note on perfect scalar fields
• Thermodynamics of k-essence
• Generalized Second Law and phantom Cosmology: accreting black holes
• First-order thermodynamics of scalar-tensor cosmology
• The effective theory of fluids at NLO and implications for dark energy
• Modelling non-dust fluids in cosmology
• Peculiar thermal states in the first-order thermodynamics of gravity
• Past-directed scalar field gradients and scalar-tensor thermodynamics
• Minimally coupled scalar fields as imperfect fluids
• Stealth metastable state of scalar-tensor thermodynamics

Cited by in corpus (13)

• More on the first-order thermodynamics of scalar-tensor and Horndeski gravity
• Past-directed scalar field gradients and scalar-tensor thermodynamics
• Interacting Scalar fields: Dark matter and early dark energy
• Thermal origin of the attractor-to-general-relativity in scalar-tensor gravity
• First-order thermodynamics of Horndeski cosmology
• First-order thermodynamics of scalar-tensor gravity
• General analysis of Noether symmetries in Horndeski gravity
• Scalar-tensor theories of gravity from a thermodynamic viewpoint
• Scalar fluid in scalar-tensor gravity from an equivalent picture of thermodynamic and fluid descriptions of gravitational dynamics
• Eckart heat-flux applicability in $F(\Phi ,X)R$ theories and the existence of temperature gradients
• Thermal channels of scalar and tensor waves in Jordan-frame scalar--tensor gravity
• Thermal description of braneworld effective theories
• Covariant single-field formulation of effective cosmological bounces