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We compare the behavior of the vacuum free energy (i.e. the Casimir energy) of various $(2+1)$-dimensional CFTs on an ultrastatic spacetime as a function of the spatial geometry. The CFTs we consider are a free Dirac fermion, the…

High Energy Physics - Theory · Physics 2023-01-11 Krai Cheamsawat , Sebastian Fischetti , Lucas Wallis , Toby Wiseman

We consider a possible `deformation' of the trace of the heat kernel on odd dimensional spheres, motivated by the calculation of the free energy of a scalar field on a discretized circle. By using an expansion in terms of the modified…

Mathematical Physics · Physics 2018-04-02 Nahomi Kan , Kiyoshi Shiraishi

We consider the finite temperature Casimir free energy acting on a spherical shell in (D+1)-dimensional Minkowski spacetime due to the vacuum fluctuations of scalar and electromagnetic fields. Dirichlet, Neumann, perfectly conducting and…

Mathematical Physics · Physics 2015-06-15 L. P. Teo

We consider (2+1)-QFT at finite temperature on a product of time with a static spatial geometry. The suitably defined difference of thermal vacuum free energy for the QFT on a deformation of flat space from its value on flat space is a UV…

High Energy Physics - Theory · Physics 2020-01-10 Krai Cheamsawat , Lucas Wallis , Toby Wiseman

This work investigates the thermal Casimir effect associated with a massive spinor field defined on a four-dimensional flat space with a circularly compactified spatial dimension whose periodicity is oriented along a vector in $xy$-plane.…

High Energy Physics - Theory · Physics 2025-09-03 Joás Venâncio , Lameque Filho , Herondy Mota , Azadeh Mohammadi

We study the free energy of four-dimensional CFTs on deformed spheres. For generic nonsupersymmetric CFTs only the coefficient of the logarithmic divergence in the free energy is physical, which is an extremum for the round sphere. We then…

High Energy Physics - Theory · Physics 2021-03-10 Joseph A. Minahan , Usman Naseer , Charles Thull

We consider relativistic (2+1)-QFTs on a product of time with a two-space and study the vacuum free energy as a functional of the temperature and spatial geometry. We focus on free scalar and Dirac fields on arbitrary perturbations of flat…

High Energy Physics - Theory · Physics 2019-05-30 Sebastian Fischetti , Lucas Wallis , Toby Wiseman

We compute the Casimir energy for a free scalar field on the spaces $\,R^{m+1}\,\times\,\tilde S^2\,$ where $,\tilde S^2\,$ is two-dimensional deformed two-sphere.

High Energy Physics - Theory · Physics 2016-09-06 N. ~Shtykov , D. ~V. ~Vassilevich

We use a functional approach to evaluate the Casimir free energy for a self-interacting scalar field in $d+1$ dimensions, satisfying Dirichlet boundary conditions on two parallel planes. When the interaction is turned off, exact results for…

High Energy Physics - Theory · Physics 2008-09-16 Claudio Ccapa Ttira , Cesar D. Fosco

The Casimir free energy for a system of two dielectric concentric nonmagnetic spherical bodies is calculated with use of a quantum statistical mechanical method, at arbitrary temperature. By means of this rather novel method, which turns…

Quantum Physics · Physics 2009-01-14 J. S. Høye , I. Brevik , J. B. Aarseth

We calculate the low temperature corrections to the free energy for a sphere in front of a plane. First, the scalar field obeying Dirichet or Neumann boundary conditions is considered. Second, the electromagnetic field is studied, the…

Quantum Physics · Physics 2015-05-19 Michael Bordag , Irina G. Pirozhenko

Casimir energy changes are investigated for geometries obtained by small but arbitrary deformations of a given geometry for which the vacuum energy is already known for the massless scalar field. As a specific case, deformation of a…

High Energy Physics - Theory · Physics 2009-11-13 H. Ahmedov , I. H. Duru

We consider polarizable sheets modeled by a lattice of delta function potentials. The Casimir interaction of two such lattices is calculated at nonzero temperature. The heat kernel expansion for periodic singular background is discussed in…

Quantum Physics · Physics 2020-02-19 Irina Pirozhenko

Quantum vacuum energy has been known to have observable consequences since 1948 when Casimir calculated the force of attraction between parallel uncharged plates, a phenomenon confirmed experimentally with ever increasing precision. Casimir…

High Energy Physics - Theory · Physics 2009-11-07 Kimball A. Milton

In this paper we compute the leading order of the Casimir energy for a free massless scalar field confined in a sphere in three spatial dimensions, with the Dirichlet boundary condition. When one tabulates all of the reported values of the…

High Energy Physics - Theory · Physics 2010-05-27 M. A. Valuyan , S. S. Gousheh

We derive an exact analytic expression for the high-temperature limit of the Casimir interaction between two Drude spheres of arbitrary radii. Specifically, we determine the Casimir free energy by using the scattering approach in the…

Quantum Physics · Physics 2021-05-31 Tanja Schoger , Gert-Ludwig Ingold

The free energy due to the vacuum fluctuations of matter fields on a classical gravitational background is discussed. It is shown explicitly how this energy is calculated for a non-minimally coupled scalar field in an arbitrary…

High Energy Physics - Theory · Physics 2007-05-23 Karsten Bormann , Frank Antonsen

We consider the Casimir effect for a sphere in front of a plane at finite temperature for scalar and electromagnetic fields and calculate the limiting cases. For small separation we compare the exact results with the corresponding ones…

Quantum Physics · Physics 2015-03-13 M. Bordag , I. Pirozhenko

Quantum vacuum energy has been known to have observable consequences since 1948 when Casimir calculated the force of attraction between parallel uncharged plates, a phenomenon confirmed experimentally with ever increasing precision. Casimir…

High Energy Physics - Theory · Physics 2016-11-09 Kimball A. Milton

We extend previous work on the vacuum energy of a massless scalar field in the presence of singular potentials. We consider a single sphere denoted by the so-called "delta-delta prime" interaction. Contrary to the Dirac delta potential, we…

High Energy Physics - Theory · Physics 2023-01-18 C. Romaniega , J. M. Munoz-Castaneda , I. Cavero-Pelaez
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