Hot scalar radiation setting bounds on the curvature coupling parameter

2019

Braz J Phys

This paper investigates further how the presence of a single reflecting plane wall modifies the usual Planckian forms in the thermodynamics of the massless scalar radiation in Ndimensional Minkowski spacetime. This is done in a rather unconventional way by integrating the energy density over space to obtain the internal energy and from that the Helmholtz free energy. The reflecting wall is modelled by assuming the Dirichlet or the Neumann boundary conditions on the wall. It is found that when N > 2 integration over space eliminates dependence on the curvature coupling parameter ξ. Unexpectedly though, when N = 2, the internal energy and the corresponding thermodynamics turn out to be dependent on ξ. For instance, the correction to the two-dimensional Planckian heat capacity is ∓ξk B (minus for Dirichlet, plus for Neumann). Other aspects of this dependence on ξ are also discussed. Results are confronted with those in the literature concerning related setups of reflecting walls (such as slabs) where conventional (i.e., global) approaches to obtain thermodynamics have been used.

Section: Resultsmentioning

confidence: 99%

Section: 2mentioning

confidence: 99%

Section: 2mentioning

confidence: 99%

“…(30) and (31) were not presented in ref. [31] for arbitrary N , but the way to obtain them is the same as that leading to eqs. (28) and (29) which appeared first in ref.…”

Section: 2mentioning

confidence: 99%

“…It should be remarked that these values fit the bounds on ξ given in the previous section [note that, as mentioned earlier, equalities are likely not discarded in eqs. (29) and (31)].…”

Section: N =2mentioning

confidence: 99%

See 3 more Smart Citations

Thermodynamics of the Scalar Radiation in the Presence of a Reflecting Plane Wall

2019

Braz J Phys

Local thermal behaviour of a massive scalar field near a reflecting wall

Lorenci

Gomes

2015

J. High Energ. Phys.

The mean square fluctuation and the expectation value of the stress-energymomentum tensor of a neutral massive scalar field at finite temperature are determined near an infinite plane Dirichlet wall, and also near an infinite plane Neumann wall. The flat background has an arbitrary number of dimensions and the field is arbitrarily coupled to the vanishing curvature. It is shown that, unlike vacuum contributions, thermal contributions are free from boundary divergences, and that the thermal behaviour of the scalar field near a Dirichlet wall differs considerably from that near a Neumann wall. Far from the wall the study reveals a local version of dimensional reduction, namely, corrections to familiar blackbody expressions are linear in the temperature, with the corresponding coefficients given only in terms of vacuum expectation values in a background with one less dimension. It is shown that such corrections are "classical" (i.e., not dependent on Planck's constant) only if the scalar field is massless. A natural conjecture that arises is that the "local dimensional reduction" is universal since it operates for massless and massive fields alike and regardless of the boundary conditions.

Hot scalar radiation around a cosmic string setting bounds on the coupling parameter ξ

2017

J. High Energ. Phys.