English
Related papers

Related papers: Damped perturbations in the no-boundary state

200 papers

We consider in this article the weakly coupled system of wave equations in the \textit{scale-invariant case} and with time-derivative nonlinearities. Under the usual assumption of small initial data, we obtain an improvement of the…

Analysis of PDEs · Mathematics 2020-08-25 Makram Hamouda , Mohamed Ali Hamza

When the universe is treated as a quantum system, it is described by a wave function. This wave function is a function not only of the matter fields, but also of spacetime. The no-boundary proposal is the idea that the wave function should…

High Energy Physics - Theory · Physics 2024-03-29 Jean-Luc Lehners

We study large traveling surface waves within a two-dimensional finite depth, free boundary, homogeneous, incompressible and viscous fluid governed by Darcy's law. The fluid is bound by a gravitational force to a flat rigid bottom and meets…

Analysis of PDEs · Mathematics 2026-01-21 Huy Q. Nguyen , Noah Stevenson

The set of coherent states for a noncommutative quantum Bianchi I anisotropic cosmology were built to circumvent the absence of a simultaneous set of configuration observables. By extending known methods of path integrals with coherent…

General Relativity and Quantum Cosmology · Physics 2014-03-13 Román Juárez , David Martínez

The border-collision normal form is a canonical form for two-dimensional, continuous maps comprised of two affine pieces. In this paper we provide a guide to the dynamics of this family of maps in the non-invertible case where the two…

Chaotic Dynamics · Physics 2023-07-19 Hammed Olawale Fatoyinbo , David J. W. Simpson

In this paper, we study input-to-state (ISS) issues for damped wave equations with Dirichlet boundary conditions on a bounded domain of dimension two. The damping term is assumed to be non-linear and localized to an open subset of the…

Optimization and Control · Mathematics 2020-11-17 Meryem Kafnemer , Benmiloud Mebkhout , Yacine Chitour

In this note, we prove blow-up results for semilinear wave models with damping and mass in the scale-invariant case and with nonlinear terms of derivative type. We consider the single equation and the weakly coupled system. In the first…

Analysis of PDEs · Mathematics 2021-04-07 Alessandro Palmieri , Ziheng Tu

The loop quantum cosmology "improved dynamics" of the Bianchi type IX model are studied. The action of the Hamiltonian constraint operator is obtained via techniques developed for the Bianchi type I and type II models, no new input is…

General Relativity and Quantum Cosmology · Physics 2014-11-21 Edward Wilson-Ewing

Sharp large deviation estimates for stochastic differential equations with small noise, based on minimizing the Freidlin-Wentzell action functional under appropriate boundary conditions, can be obtained by integrating certain matrix Riccati…

Statistical Mechanics · Physics 2023-01-11 Timo Schorlepp , Tobias Grafke , Rainer Grauer

We study linear perturbations about a dust filled Bianchi Type I model with the vorticity set to zero. In comparison to linear perturbations about FLRW models, modes of perturbations about Bianchi type I models are coupled. We find that the…

General Relativity and Quantum Cosmology · Physics 2015-04-09 Bob Osano

The study of stability of gravitational perturbations in higher derivative gravity has shown that at the linear level the massive unphysical ghost is not generated from vacuum if the initial seed of metric perturbation has frequency…

General Relativity and Quantum Cosmology · Physics 2019-09-11 Simpliciano Castardelli dos Reis , Grigori Chapiro , Ilya L. Shapiro

The article is devoted to investigating the initial boundary value problem for the damped wave equation in the scale-invariant case with time-dependent speed of propagation on the exterior domain. By presenting suitable multipliers and…

Analysis of PDEs · Mathematics 2023-11-28 Makram Hamouda , Mohamed Ali Hamza , Bouthaina Yousfi

We analyze new phenomena arising in linear damped wave equations on unbounded domains when the damping is allowed to become unbounded at infinity. We prove the generation of a contraction semigroup, study the relation between the spectra of…

Spectral Theory · Mathematics 2018-02-22 Pedro Freitas , Petr Siegl , Christiane Tretter

Motivated by the recent interest in dynamical properties of topologically nontrivial spacetimes, we study linear perturbations of spatially closed Bianchi III vacuum spacetimes, whose spatial topology is the direct product of a higher genus…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Masayuki Tanimoto , Vincent Moncrief , Katsuhito Yasuno

The study of fourth order partial differential equations has flourished in the last years, however, a $p(\cdot)$-biharmonic problem with no-flux boundary condition has never been considered before, not even for constant $p$. This is an…

Analysis of PDEs · Mathematics 2016-11-02 Maria-Magdalena Boureanu , Vicenţiu Rădulescu , Dušan Repovš

This work is directed towards investigating the fate of three-dimensional long perturbation waves in a plane incompressible wake. The analysis is posed as an initial-value problem in space. More specifically, input is made at an initial…

Fluid Dynamics · Physics 2015-03-13 S. Scarsoglio , D. Tordella , W. O. Criminale

Our interest itself of this paper is strongly inspired from an open problem in the paper [1] published by D'Abbicco. In this article, we would like to study the Cauchy problem for a weakly coupled system of semi-linear structurally damped…

Analysis of PDEs · Mathematics 2019-11-12 Tuan Anh Dao

Quantum effects on a pair of Bateman oscillators embedded in an ambient noncommutative space (Moyal plane) is analyzed using both path integral and canonical quantization schemes within the framework of Hilbert-Schmidt operator formulation.…

Quantum Physics · Physics 2018-06-20 Sayan Kumar Pal , Partha Nandi , Biswajit Chakraborty

We present the affine coherent state quantization of the Bianchi I model. As in our previous paper on quantum theory of Friedmann models, we employ a variable associated with a perfect fluid to play a role of clock. Then we deparameterize…

General Relativity and Quantum Cosmology · Physics 2015-07-06 Herve Bergeron , Andrea Dapor , Jean-Pierre Gazeau , Przemyslaw Malkiewicz

We show that, in ideal-spin hydrodynamics, the components of the spin tensor follow damped wave equations. The damping rate is related to nonlocal collisions of the particles in the fluid, which enter at first order in $\hbar$ in a…

Nuclear Theory · Physics 2025-02-10 David Wagner , Masoud Shokri , Dirk H. Rischke