Quantum and thermal pressures from light scalar fields

TL;DR

This paper derives expressions for quantum and thermal pressures caused by light scalar fields between parallel plates, highlighting their significance in experiments and analyzing various scalar field models like chameleon and symmetron.

Contribution

It introduces the calculation of thermal pressures from light scalar fields and demonstrates their potential to match or surpass quantum pressures in experimental setups.

Findings

Thermal pressures can be comparable to quantum pressures in scalar field experiments.

Large regions in parameter space allow thermal pressures to be experimentally significant.

Thermal pressures from chameleon fields can be of experimental relevance.

Abstract

Light scalar fields play a variety of roles in modern physics, especially in cosmology and modified theories of gravity. For this reason, there is a zoo of experiments actively trying to find evidence for many scalar field models that have been proposed in theoretical considerations. Among those are setups in which the pressures expected to be induced by light scalar fields between two parallel plates are studied, for example, Casimir force experiments. While it is known that classical and quantum pressures caused by light scalar fields could have significant impacts on such experiments, in this article, we show that this can also be the case for thermal pressure. More specifically, we derive expressions for the quantum and thermal pressures induced by exchanges of light scalar field fluctuations between two thin parallel plates. As particular examples, we then look at screened scalar fields. For chameleon, symmetron and environment-dependent dilaton models, we find large regions in their parameter spaces that allow for thermal pressures to equal or exceed the quantum pressures. By comparing with earlier constraints from quantum pressure calculations, we conclude that thermal pressures induced by chameleons are actually of experimental significance.