June 28, 2004
There has been considerable interest in providing new limits on the short range behaviour of gravity, or, in general, anomalous short-range interactions. In this note we show that one use the interaction of ultra-cold neutrons to obtain a better limit below about 10 nm.
April 5, 2024
It is well known that the cosmological constant term in the Einstein field equations can be interpreted as a stress tensor for dark energy. This stress tensor is formally analogous to an elastic constitutive equation in continuum mechanics. As a result, the cosmological constant leads to a "shear modulus" and "bulk modulus" affecting all gravitational fields in the universe. The form of the constitutive equation is also analogous to the London constitutive equation for a supe...
May 11, 2023
Neutron stars are one of the most mysterious wonders in the Universe. Their extreme densities hint at new and exotic physics at work within. Gravitational waves could be the key to unlocking their secrets. In particular, a first detection of gravitational waves from rapidly-spinning, deformed neutron stars could yield new insights into the physics of matter at extreme densities and under strong gravity. Once a first detection is made, a critical challenge will be to robustly ...
June 11, 2002
The issue of whether some manifestations of gravitation in the quantum domain, are indicative or not of a non-geometrical aspect in gravitation is discussed. We examine some examples that have been considered in this context, providing a critical analysis of previous interpretations. The analysis of these examples is illustrative about certain details in the interpretation of quantum mechanics. We conclude that there are, at this time, no indications of such departure from th...
August 4, 2006
The electromagnetic measurements of general relativistic gravitomagnetic effects which can be performed within a conductor embedded in the space-time of slow rotating gravitational object in the presence of magnetic field are proposed.
July 17, 2022
The response of a superconductor to a gravitational wave is shown to obey a London-like constituent equation. The Cooper pairs are described by the Ginzburg-Landau free energy density embedded in curved spacetime. The lattice ions are modeled by quantum harmonic oscillators characterized by quasi-energy eigenvalues. This formulation is shown to predict a dynamical Casimir effect since the zero-point energy of the ionic lattice phonons is modulated by the gravitational wave. I...
October 4, 2006
It is well known that a rotating superconductor produces a magnetic field proportional to its angular velocity. The authors conjectured earlier, that in addition to this so-called London moment, also a large gravitomagnetic field should appear to explain an apparent mass increase of Niobium Cooper-pairs. A similar field is predicted from Einstein's general relativity theory and the presently observed amount of dark energy in the universe. An experimental facility was designed...
February 1, 2006
In this paper we very preliminarily investigate the possibility of measuring the post-Newtonian general relativistic gravitoelectric and gravitomagnetic components of the acceleration of gravity on the Earth, in continuous regime, with two absolute measurements at the equator and the south pole with superconducting gravimeters. The magnitudes of such relativistic effects are 10^-10 m s^-2 and 10^-11 m s^-2, respectively. Unfortunately, the present-day uncertainties in the Ear...
July 3, 2006
A gravitomagnetic analogue of the London moment in superconductors can explain the anomalous Cooper pair mass excess reported by Janet Tate. Ultimately the gravitomagnetic London moment is attributed to the breaking of the principle of general covariance in superconductors. This naturally implies non-conservation of classical energy-momentum. Possible relation with the manifestation of dark energy in superconductors is questioned.
March 4, 2016
Following the ideas of effective field theories, we derive classically effective field equations of recently developed Lorentz gauge theory of gravity. It is shown that Newton's gravitational constant emerges as an effective coupling parameter if an extremely small length is integrated out of the underlying theory. The linear version of the effective theory is shown to be fully consistent with the Newtonian gravity. We also derive a numerical solution for the interior of a st...