Falling from Rest: Particle Creation in a Dropped Cavity

We discuss the process of particle creation in the case of a scalar quantum field confined to a small cavity, initially at rest, which is suddenly dropped in a static gravitational field. We show that, due to the transition from a Schwarzschild to a Minkowski background, as perceived by a comoving observer, field particles are excited out of the quantum vacuum. The density of the created quanta depends on the proper gravitational acceleration as well as on a parameter α≃1/Δt, with Δt representing the typical time duration of the transition. For the specific acceleration profile considered, the energy spectrum of the created quanta roughly resembles a two-dimensional Planckian distribution, whose equivalent temperature mimics the Hawking-Unruh temperature, with the detector acceleration (or the black hole surface gravity) replaced by the parameter cα. We briefly comment on possible issues related to local Lorentz symmetry.

Exploiting Weak Field Gravity-Maxwell Symmetry in Superconductive Fluctuations Regime

We study the behaviour of a superconductor in a weak static gravitational field for temperatures slightly greater than its transition temperature (fluctuation regime). Making use of the time-dependent Ginzburg–Landau equations, we find a possible short time alteration of the static gravitational field in the vicinity of the superconductor, providing also a qualitative behaviour in the weak field condition. Finally, we compare the behaviour of various superconducting materials, investigating which parameters could enhance the gravitational field alteration.

Is Gravity, The Curvature of Spacetime or A Quantum Phenomenon?

Gravity is the curvature of spacetime, the structural property of static gravitational field, a geometric field, in curved coordinates, according the functions guv, that express geometric relations. Course, general relativity is a relational theory, however, gravity, a thinking category, has symetric physical effects with matter. Throught of relativist aether was attempted transform spacetime in a substantia without succes, the consequence was return to problematic geometric field. The philosophy of the science intervenes, and according the substantialist theory spacetime is a inmaterial, geometric substantia. Then, the metaphysics arrives to a full solution in the super-substantivalist theory, that affirms: matter arises from geometric spacetime. Thus, it explains consistently the symetric physical effects between spacetime and matter. Surely, this solution is a medieval speculation. Our goal is driver the debate on gravity, to the arena of the quantum physics, but without the ballast of the general relativity. Â Â