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We prove the global leading-order late-time asymptotic behaviour of solutions to inhomogeneous wave equations on dynamical black hole exterior backgrounds that settle down to Schwarzschild backgrounds with arbitrarily small decay rates. In…

General Relativity and Quantum Cosmology · Physics 2025-12-01 Dejan Gajic , Lionor Kehrberger

We describe a new numerical algorithm for ray tracing in the external spacetimes of spinning compact objects characterized by arbitrary quadrupole moments. Such spacetimes describe non-Kerr vacuum solutions that can be used to test the…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Dimitrios Psaltis , Tim Johannsen

We investigate how the resolution of the singularity problem for the Schwarzschild BH could be related to the presence of quantum gravity effects at horizon scales. Motivated by the analogy with the cosmological Schwarzschild-dS solution,…

General Relativity and Quantum Cosmology · Physics 2022-07-19 Mariano Cadoni , Mauro Oi , Andrea Pierfrancesco Sanna

We consider a model initial- and Dirichlet boundary- value problem for a linearized Cahn-Hilliard-Cook equation, in one space dimension, forced by the space derivative of a space-time white noise. First, we introduce a canvas problem the…

Numerical Analysis · Mathematics 2017-07-10 Georgios E. Zouraris

Rapidly rotating black hole solutions in theories beyond general relativity play a key role in experimental gravity, as they allow us to compute observables in extreme spacetimes that deviate from the predictions of general relativity. Such…

General Relativity and Quantum Cosmology · Physics 2016-11-29 Robert McNees , Leo C. Stein , Nicolás Yunes

We propose a novel solution for the endpoint of gravitational collapse, in which spacetime ends (and is orbifolded) at a microscopic distance from black hole event horizons. This model is motivated by the emergence of singular event…

High Energy Physics - Theory · Physics 2013-12-03 Mehdi Saravani , Niayesh Afshordi , Robert B. Mann

This paper investigates boundary hemivariational inequality problems associated with both stationary and non-stationary two and three-dimensional convective Brinkman-Forchheimer equations (or Navier-stokes equations with damping), which…

Analysis of PDEs · Mathematics 2025-08-26 Jyoti Jindal , Sagar Gautam , Manil T. Mohan

We discuss Green's-function solutions of the equation for a geometrically thin, axisymmetric Keplerian accretion disc with a viscosity prescription "\nu ~ R^n". The mathematical problem was solved by Lynden-Bell & Pringle (1974) for the…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Takamitsu Tanaka

In this paper, we design and analyze a Hybrid-High Order (HHO) approximation for a class of quasilinear elliptic problems of nonmonotone type. The proposed method has several advantages, for instance, it supports arbitrary order of…

Numerical Analysis · Mathematics 2021-11-01 Thirupathi Gudi , Gouranga Mallik , Tamal Pramanick

For the planar $N$-body problem, we first introduce a class of moving frame suitable for orbits near central configurations, especially for total collision orbits, which is the main new ingredient of this paper. The moving frame allows us…

Dynamical Systems · Mathematics 2021-06-29 Xiang Yu

We study the Cauchy problem for the sine-Gordon equation in the semiclassical limit with pure-impulse initial data of sufficient strength to generate both high-frequency rotational motion near the peak of the impulse profile and also…

Mathematical Physics · Physics 2011-06-29 Robert J. Buckingham , Peter D. Miller

The aim of the paper is to study an optimal control problem on infinite horizon for an infinite dimensional integro-differential equation with completely monotone kernelskernels, where we assume that the noise enters the system when we…

Optimization and Control · Mathematics 2016-10-31 Elisa Mastrogiacomo

In this letter, we analytically describe the typical solution time needed by a backtracking algorithm to solve the vertex-cover problem on finite-connectivity random graphs. We find two different transitions: The first one is…

Disordered Systems and Neural Networks · Physics 2009-10-31 Martin Weigt , Alexander K. Hartmann

The behavior of solutions of the finite-genus Whitham equations for the weak dispersion limit of the defocusing nonlinear Schrodinger equation is investigated analytically and numerically for piecewise-constant initial data. In particular,…

Exactly Solvable and Integrable Systems · Physics 2009-11-11 Gino Biondini , Yuji Kodama

In this work, we prove that the classical Schwarzschild-de Sitter spacetime is an exact solution of a class of weakly non-local, UV finite conformal quantum gravity theories, without the necessity of including a cosmological constant term…

General Relativity and Quantum Cosmology · Physics 2025-10-08 Diego A. Martínez-Valera

We consider weakly non-linear gravitational perturbations of a near-extremal Kerr black hole governed by the second order vacuum Einstein equation. Using the GHZ formalism [Green et al., Class. Quant. Grav. 7(7):075001, 2020], these are…

General Relativity and Quantum Cosmology · Physics 2024-12-05 Claudio Iuliano , Stefan Hollands , Stephen R. Green , Peter Zimmerman

The "flexible boundary condition" method, introduced by Sinclair and coworkers in the 1970s, remains among the most popular methods for simulating isolated two-dimensional crystalline defects, embedded in an effectively infinite atomistic…

Numerical Analysis · Mathematics 2021-10-15 M. Hodapp

We develop efficient and high-order accurate solvers for the Helmholtz equation on complex geometry. The schemes are based on the WaveHoltz algorithm which computes solutions of the Helmholtz equation by time-filtering solutions of the wave…

Numerical Analysis · Mathematics 2025-04-07 Daniel Appelo , Jeffrey W. Banks , William D. Henshaw , Donald W. Schwendeman

In this article, we addressed the numerical solution of a non-linear evolutionary variational inequality, which is encountered in the investigation of quasi-static contact problems. Our study encompasses both the semi-discrete and…

Numerical Analysis · Mathematics 2024-01-05 Kamana Porwal , Tanvi Wadhawan

We study nonnegative solutions to the Cauchy problem for the Fractional Fast Diffusion Equation on a suitable class of connected, noncompact Riemannian manifolds. This parabolic equation is both singular and nonlocal: the diffusion is…

Analysis of PDEs · Mathematics 2025-03-27 Elvise Berchio , Matteo Bonforte , Gabriele Grillo