arXiv subjects

K. Rébora

Publications and source records attributed to K. Rébora.

3 recordsLinked to original sources

arXiv2001

Casimir energy for spherically symmetric dispersive dielectric media

We consider the vacuum energy of the electromagnetic field in the background of spherically symmetric dielectrics, subject to a cut-off frequency in the dispersion relations. The effect of this frequency dependent boundary condition between media is described in terms of the {\it incomplete} $ζ$-functions of the problem. The use of the Debye asymptotic expansion for Bessel functions allows to determine the dominant (volume, area, ...) terms in the Casimir energy. The application of these expressions to the case of a gas bubble immersed in water is discussed, and results consistent with Schwinger's proposal about the role the Casimir energy plays in sonoluminescence are found. PACS: 03.70.+k,12.20.Ds,78.60.Mq

hep-th↗

arXiv2001

Divergencies in the Casimir energy for a medium with realistic ultraviolet behavior

We consider a dielectric medium with an ultraviolet behavior as it follows from the Drude model. Compared with dilute models, this has the advantage that, for large frequencies, two different media behave the same way. As a result one expects the Casimir energy to contain less divergencies than for the dilute media approximation. We show that the Casimir energy of a spherical dielectric ball contains just one divergent term, a volume one, which can be renormalized by introducing a contact term analogous to the volume energy counterterm needed in bag models. PACS: 12.20.Ds, 03.70.+k, 77.22.Ch

hep-th↗

arXiv2000

Casimir energy for a scalar field with a frequency dependent boundary condition

We consider the vacuum energy for a scalar field subject to a frequency dependent boundary condition. The effect of a frequency cut-off is described in terms of an {\it incomplete} $ζ$-function. The use of the Debye asymptotic expansion for Bessel functions allows to determine the dominant (volume, area, >...) terms in the Casimir energy. The possible interest of this kind of models for dielectric media (and its application to sonoluminescence) is also discussed.

hep-th↗