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Motivated by the vast string landscape, we consider the shear viscosity to entropy density ratio in conformal field theories dual to Einstein gravity with curvature square corrections. After field redefinitions these theories reduce to…

High Energy Physics - Theory · Physics 2010-04-06 Mauro Brigante , Hong Liu , Robert C. Myers , Stephen Shenker , Sho Yaida

Rotation curves of spiral galaxies are known with reasonable precision for a large number of galaxies with similar morphologies. The data implies that non-Keplerian fall--off is seen. This implies that (i) large amounts of dark matter must…

Astrophysics · Physics 2011-05-23 C. Rodrigo-Blanco , J. Pérez-Mercader

A novel methodology for analysing the relation between the energy density in gravitational waves and primordial power spectra is developed. Focusing on scalar-induced gravitational radiation, this methodology is applied to a number of…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-14 Daniel Frolovsky , Florian Kuhnel , Ioanna Stamou

The gravitational field of an isolated, axisymmetric flat disk of spinning dust is calculated approximately in the weak-field limit of quasi-metric gravity. Boundary conditions single out the exponential disk as a "preferred" physical…

General Relativity and Quantum Cosmology · Physics 2024-03-26 Dag Østvang

Gravity is the driving force of star formation. Although gravity is caused by the presence of matter, its role in complex regions is still unsettled. One effective way to study the pattern of gravity is to compute the accretion it exerts on…

Astrophysics of Galaxies · Physics 2023-08-09 Zhen-Zhen He , Guang-Xing Li , Andreas Burkert

We consider the optimization of a neural network previously developed by the authors for the joint inversion of 3D gravitational and magnetic fields in the context of mineral exploration. The distinctive feature of this neural network is…

We have developed a method based on wavelets to obtain the true underlying smooth density from a point distribution. The goal has been to reconstruct the density field in an optimal way ensuring that the morphology of the reconstructed…

Astrophysics · Physics 2009-11-13 V. J. Martinez , J. -L. Starck , E. Saar , D. L. Donoho , S. Reynolds , P. de la Cruz , S. Paredes

In this Note, a new approach to spacecraft positioning based on GGT inversion is presented. The gravity gradient tensor is initially measured in the gradiometer reference frame (GRF) and then transformed to the Earth-Centered Earth-Fixed…

Instrumentation and Methods for Astrophysics · Physics 2016-08-12 Pei Chen , Xiucong Sun , Chao Han

Typical geophysical inversion problems are ill-posed, non-linear and non-unique. Sometimes the problem is trans-dimensional, where the number of unknown parameters is one of the unknowns, which makes the inverse problem even more…

Geophysics · Physics 2010-02-25 Xiaolin Luo

In this manuscript, we show how conformal invariance can be incorporated in a classical theory of gravitation, in the context of metric measure space. Metric measure space involves a geometrical scalar $f$, dubbed as density function, which…

General Relativity and Quantum Cosmology · Physics 2016-09-07 Nafiseh Rahmanpour , Hossein Shojaie

In the effective field theory approach to gravity, the Lagrangian density for general relativity is supplemented by generally covariant terms of higher order in the Riemann tensor and its derivatives. At face value, these terms will result…

General Relativity and Quantum Cosmology · Physics 2024-09-25 Dražen Glavan , Shinji Mukohyama , Tom Zlosnik

A new inversion method for determining near-surface shear currents from a measured wave spectrum is introduced. The method is straightforward to implement and starts from the existing state-of-the-art technique of assigning effective depths…

Atmospheric and Oceanic Physics · Physics 2020-02-19 Benjamin K. Smeltzer , Eirik Æsøy , Anna Ådnøy , Simen Å. Ellingsen

Within the weak-field approximation of general relativity, new exact solutions are derived for the gravitational field of a mass moving with arbitrary velocity and acceleration. A mass having a constant velocity greater than 3^-1/2 times…

General Relativity and Quantum Cosmology · Physics 2009-02-10 F. S. Felber

Effective Field Theory techniques are used to study the leading order quantum corrections to the gravitational wave backreaction. The effective stress-energy tensor is calculated and it is shown that it has a non-vanishing trace that…

General Relativity and Quantum Cosmology · Physics 2018-01-03 Iberê Kuntz

The measurement of the integrated optical polarization of weakly gravitationally lensed galaxies can provide considerable constraints on lens models. The method outlined depends on fact that the orientation of the direction of optical…

Astrophysics · Physics 2009-10-30 Edouard Audit , John F. L. Simmons

The structure of the divergences for transverse theories of gravity is studied to one-loop order. These theories are invariant only under those diffeomorphisms that enjoy unit Jacobian determinant (TDiff), so that the determinant of the…

High Energy Physics - Theory · Physics 2008-11-26 Enrique Alvarez , Anton F. Faedo , J. J. Lopez-Villarejo

Inversion methodology has been used to obtain, from multi-layer soil probes records, a complete soil parametrisation, namely water retention curve, unsaturated conductivity curve and bulk density at 4 depths. The approach integrates water…

Geophysics · Physics 2018-05-18 Giuliano Vitali , Mirco Iotti , Alessandra Zambonelli

The onset of condensation of hard spheres in a gravitational field is studied using density functional theory. In particular, we find that the local density approximation yields results identical to those obtained previously using the…

Statistical Mechanics · Physics 2009-11-07 Joseph A. Both , Daniel C. Hong

A second gradient generalization of Newtonian gravity is presented within the framework of gradient field theory. Weak nonlocality is introduced via first and second gradients of the gravitational field strength in the Lagrangian density.…

General Relativity and Quantum Cosmology · Physics 2020-12-02 Markus Lazar

Gravitational lensing by a spinning deflector in translational motion relative to the observer is discussed in the weak field, slow motion approximation. The effect of rotation, which generates an intrinsic gravito-magnetic field, separates…

Astrophysics · Physics 2009-11-10 M. Sereno