Towards measuring variations of Casimir energy by a superconducting cavity

We consider a Casimir cavity, one plate of which is a thin superconducting film. We show that when the cavity is cooled below the critical temperature for the onset of superconductivity, the sharp variation (in the far infrared) of the reflection coefficient of the film engenders a variation in the value of the Casimir energy. Even though the relative variation in the Casimir energy is very small, its magnitude can be comparable to the condensation energy of the superconducting film, and this gives rise to a number of testable effects, including a significant increase in the value of the critical magnetic field, required to destroy the superconductivity of the film. The theoretical ground is therefore prepared for the first experiment ever aimed at measuring variations of the Casimir energy itself.Comment: 4 pages, 2 figures. Substantial improvement of presentation, choice of a more convenient cavity geometry. Accepted for publication in Phys. Rev. Let

On the photon Green functions in curved space-time

Quantization of electrodynamics in curved space-time in the Lorenz gauge and with arbitrary gauge parameter makes it necessary to study Green functions of non-minimal operators with variable coefficients. Starting from the integral representation of photon Green functions, we link them to the evaluation of integrals involving Gamma functions. Eventually, the full asymptotic expansion of the Feynman photon Green function at small values of the world function, as well as its explicit dependence on the gauge parameter, are obtained without adding by hand a mass term to the Faddeev--Popov Lagrangian. Coincidence limits of second covariant derivatives of the associated Hadamard function are also evaluated, as a first step towards the energy-momentum tensor in the non-minimal case.Comment: 22 pages, plain Tex. All sections and appendices have been improve

A multiscale approach to triglycerides simulations: from atomistic to coarse-grained models and back

The aim of this paper is to provide a simulation strategy to study the liquid-solid transition of triglycerides. The strategy is based on a multiscale approach. A coarse-grained model, parameterized on the basis of reference atomistic simulations, has been used to model the liquid-solid transition. A reverse mapping procedure has been proposed to reconstruct atomistic models from coarse-grained configurations and validated against experimental structural properties. The nucleation and growth of the crystalline order have been analysed in terms of several properties