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Many astrophysical phenomena exhibit relativistic radiative flows. While velocities in excess of $v \sim 0.1c$ can occur in these systems, it has been common practice to approximate radiative transfer to $\cO(v/c)$. In the case of neutrino…

Astrophysics · Physics 2007-05-23 Christian Y. Cardall , Eric J. Lentz , Anthony Mezzacappa

We present a method for extracting gravitational radiation from a three-dimensional numerical relativity simulation and, using the extracted data, to provide outer boundary conditions. The method treats dynamical gravitational variables as…

If the universe is finite and smaller than the distance to the surface of last scatter, then the signature of the topology of the universe is writ on the microwave background sky. Previous efforts to search for this topology have focused on…

General Relativity and Quantum Cosmology · Physics 2016-02-09 Neil J. Cornish , David N. Spergel , Glenn D. Starkman

We extend a recent breakthrough result relating expectation thresholds and actual thresholds to include some rainbow versions.

Combinatorics · Mathematics 2023-12-25 Tolson Bell , Alan Frieze , Trent G. Marbach

We study some aspects when one consider the existence of one extra-dimension in addition to a non-commutative space-time. We present here two different examples, where the first one provides a scenario were it is possible to relate the…

High Energy Physics - Theory · Physics 2019-02-05 M. Dias

This paper is the fourth in a series dedicated to the mathematically rigorous asymptotic analysis of gravitational radiation under astrophysically realistic setups. It provides an overview of the physical ideas involved in setting up the…

General Relativity and Quantum Cosmology · Physics 2025-08-20 Lionor Kehrberger

A slip on a paper concerning near-vector spaces is fixed. New characterization of near-vector spaces determined by finite fields is provided and the number (up to the isomorphism) of these spaces is exhibited.

Commutative Algebra · Mathematics 2016-12-12 Kijti Rodtes , Wilasinee Chomjun

Gravitational tidal forces acting on the virtual e+ e- cloud surrounding a photon endow spacetime with a non-trivial refractive index. This has remarkable properties unique to gravitational theories including superluminal low-frequency…

High Energy Physics - Theory · Physics 2012-06-20 Timothy J. Hollowood , Graham M. Shore

Often some interesting or simply curious points are left out when developing a theory. It seems that one of them is the existence of an upper bound for the fraction of area of a convex and closed plane area lying outside a circle with which…

General Mathematics · Mathematics 2007-05-23 Jose M. Pacheco

Several physical systems can be treated as a scattering process, and, for these processes, a natural observed quantity arises: the ratio between the reflected and incident intensities, known as the reflection coefficient. This dissertation…

General Relativity and Quantum Cosmology · Physics 2014-07-15 Bruno Arderucio

Recently, there has been much interest in black hole echoes, based on the idea that there may be some mechanism (e.g., from quantum gravity) that waves/fields falling into a black hole could partially reflect off of an interface before…

General Relativity and Quantum Cosmology · Physics 2023-10-03 Conner Dailey , Niayesh Afshordi , Erik Schnetter

Finding reliably and efficiently the spectrum of the resonant states of an optical system under varying parameters of the medium surrounding it is a technologically important task, primarily due to various sensing applications.…

Optics · Physics 2023-09-28 S. F. Almousa , E. A. Muljarov

We survey recent developments on rationality problems for algebraic varieties, with a particular emphasis on cycle-theoretic and combinatorial methods and their applications to hypersurfaces.

Algebraic Geometry · Mathematics 2026-04-02 Stefan Schreieder

Let $X$ be an algebraic variety, defined over the rationals. This paper gives upper bounds for the number of rational points on $X$, with height at most $B$, for the case in which $X$ is a curve or a surface. In the latter case one excludes…

Number Theory · Mathematics 2007-05-23 D. R. Heath-Brown , J. -L. Colliot-Thélène

We report a numerical evolution of axisymmetric Brill waves. The numerical algorithm has new features, including (i) a method for keeping the metric regular on the axis and (ii) the use of coordinates that bring spatial infinity to the edge…

General Relativity and Quantum Cosmology · Physics 2009-10-31 David Garfinkle , G. Comer Duncan

Algebraic surfaces in the complex projective space with a high number of A-type singularities have been presented in a recent paper. We extend the construction in order to obtain lower bounds for the maximal number of A singularities for…

Algebraic Geometry · Mathematics 2026-05-25 Juan García Escudero

Many natural patterns and shapes, such as meandering coastlines, clouds, or turbulent flows, exhibit a characteristic complexity mathematically described by fractal geometry. In recent years, the engineering of self-similar structures in…

We calculate deviations in cosmological observables as a function of parameters in a class of connection-based models of quantum gravity. In this theory non-trivial modifications to the background cosmology can occur due to a distortion of…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-01 Michael W. Toomey , Savvas Koushiappas , Bruno Alexandre , João Magueijo

We apply a variant of the square-sieve to produce a uniform upper bound for the number of rational points of bounded height on a family of surfaces that admit a fibration over the projective line, whose general fibre is a hyperelliptic…

Number Theory · Mathematics 2021-09-28 Dante Bonolis , Tim Browning

In this paper, we present a comprehensive system for the treatment of the topic of limits--conceptually, computationally, and formally. The system addresses fundamental linguistic flaws in the standard presentation of limits, which attempts…

General Mathematics · Mathematics 2007-05-23 Frank Swenton