Related papers: Rotation, Equivalence Principle, and GP-B Experime…
In the Einstein--Gauss--Bonnet (EGB) gravity models, the slow-roll approximation has been extended by taking into account the first-order slow-roll parameter $\delta_1 =-2\,H^2\,\xi^\prime/U_0$, which is proportional to the first derivative…
Gamma Ray Bursts (GRBs) with rapid variations at cosmological distances are used to place new limits on violations of the gravitational weak equivalence principle (WEP). These limits track intrinsic timing deviations between GRB photons of…
We explore the potential variation of two fundamental constants, the fine-structure constant $\alpha$ and the proton-to-electron mass ratio $\mu$, within the framework of modified gravity theories and finite-temperature effects. Utilising…
In the framework of general relativity (GR), gravitational waves (GWs) travel at the speed of light across all frequencies. However, massive gravity and weak equivalence principle (WEP) violation may lead to frequency-dependent variations…
First and second order corrections for the scattering of different types of particles by a weak gravitational field, treated as an external field, are calculated. These computations indicate a violation of the Equivalence Principle: to…
The Generalized Uncertainty Principle (GUP) has been directly applied to the motion of (macroscopic) test bodies on a given space-time in order to compute corrections to the classical orbits predicted in Newtonian Mechanics or General…
Continuing our earlier work on the application of the Relativistic Generalized Uncertainty Principle (RGUP) to quantum field theories, in this paper we study Quantum Electrodynamics (QED) with minimum length. We obtain expressions for the…
This paper investigates the orbital dynamics and gravitational wave radiation characteristics of neutral test particles around a static spherically symmetric charged black hole (BH) in 4D Einstein-Gauss-Bonnet (4D-EGB) gravity theory. We…
This white paper is submitted as part of Snowmass2013 (subgroup CF2). The extraordinary sensitivity of torsion-balances can be used to search for the ultra-feeble forces suggested by attempts to unify gravity with the other fundamental…
We consider a certain extension of the Einstein's elevator thought experiment by assuming that the elevator is charged and falls into an electromagnetic field. We argue, on grounds of the Equivalence Principle, that an observer-dependent…
In this work some aspects of the detection of certain general relativistic effects in the weak gravitational field of the Earth via laser-ranged data to some existing or proposed geodetic satellites are examined. The focus is on the…
The well known general relativistic Lense-Thirring drag of the orbit of a test particle in the stationary field of a central slowly rotating body is generated, in the weak-field and slow-motion approximation of General Relativity, by a…
We report a search for new gravitational physics phenomena based on Einstein-Cartan theory of General Relativity including spacetime torsion. Starting from the parametrized torsion framework of Mao, Tegmark, Guth and Cabi, we analyze the…
We tested the equivalence principle at short length scales by rotating a 3-ton $^{238}$U attractor around a compact torsion balance containing Cu and Pb test bodies. The observed differential acceleration of the test bodies toward the…
The Einstein equivalence principle is based on the equality of gravitational mass and inertial mass, which has led to the universality of a free-fall concept. The principle has been extremely well tested so far and has been tested with a…
With quantitative numerical simulations we show that the secular variations of the even zonal harmonics of the geopotential do affect the measurement of the Lense-Thirring effect with the nodes of LAGEOS and LAGEOS II at a \sim 14% level.…
A hybrid model which allows to interpolate between the (original) Regge approach and dynamical triangulations is introduced. The gained flexibility in the measure is exploited to study dynamical triangulation in a fixed geometry. Our…
We consider models of Extended Gravity and in particular, generic models containing scalar-tensor and higher-order curvature terms, as well as a model derived from noncommutative spectral geometry. Studying, in the weak-field approximation,…
We report an improved test of the weak equivalence principle by using a simultaneous $^{85}$Rb-$^{87}$Rb dual-species atom interferometer. We propose and implement a four-wave double-diffraction Raman transition scheme for the…
We point out that the universality of free-fall can be tested by observing surface-gravity changes of the Earth. The Earth's inner core is weakly coupled to the rest part of the Earth by mainly gravitational forces. If there were a…