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Blowing-up solutions for semi-linear Klein-Gordon equations are considered in Friedmann-Lema\^itre-Robertson-Walker spacetimes. Some sufficient conditions are shown by applying the concavity method for semi-linear wave equations in the…

Analysis of PDEs · Mathematics 2025-05-15 Makoto Nakamura , Takuma Yoshizumi

We review how unitarity and stationarity in the Schwinger-Keldysh formalism naturally lead to a (quantum) generalized fluctuation-dissipation relation (gFDR) that works beyond thermal equilibrium. Non-Gaussian loop corrections are also…

Statistical Mechanics · Physics 2023-09-04 Xinyi Chen-Lin

We analyze the Wheeler-DeWitt (WDW) equation in the context of a gravitational collapse. The physics of an expanding/collapsing universe and many details of a collapsing star can classically be described by the Roberston-Walker metric in…

General Relativity and Quantum Cosmology · Physics 2024-01-17 Davide Batic , Marek Nowakowski

The field theoretic renormalization group is applied to a simple model of random walk on a rough fluctuating surface. We consider the Fokker--Planck equation for a particle in a uniform gravitational field. The surface is modelled by the…

Statistical Mechanics · Physics 2023-03-10 N. V. Antonov , N. M. Gulitskiy , P. I. Kakin , D. A. Kerbitskiy

By applying the recently developed Loop Regularization(LR) with string-mode regulators to supersymmetric field theories, we explicitly verify the supersymmetric Ward identities in several supersymmetric models at one-loop level. It is…

High Energy Physics - Phenomenology · Physics 2009-12-04 Jian-Wei Cui , Yong Tang , Yue-Liang Wu

A straight-forward interpretation of standard Friedmann-Lemaitre-Robertson-Walker (FLRW) cosmologies is that objects move apart due to the expansion of space, and that sufficiently distant galaxies must be receding at velocities exceeding…

Astrophysics · Physics 2009-11-13 Geraint F. Lewis , Matthew J. Francis , Luke A. Barnes , J. Berian James

We find a simple modification of the longitudinal mode in General Relativity which incorporates the idea of limiting curvature. In this case the singularities in contracting Friedmann and Kasner universes are avoided, and instead, the…

General Relativity and Quantum Cosmology · Physics 2017-04-18 Ali H. Chamseddine , Viatcheslav Mukhanov

Higher dimensional closed Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe with positive cosmological constant is investigated by Regge calculus. A Cauchy surface of discretized FLRW universe is replaced by a regular polytope in…

General Relativity and Quantum Cosmology · Physics 2022-03-09 Ren Tsuda , Takanori Fujiwara

The large deviation function has been known for a long time in the literature for the displacement of the rightmost particle in a branching random walk (BRW), or in a branching Brownian motion (BBM). More recently a number of…

Mathematical Physics · Physics 2016-05-25 Bernard Derrida , Zhan Shi

A specific Friedmann-Roberstson-Walker (FRW) model derived from the theory of N=1 supergravity with gauged supermatter is considered in this paper. The supermatter content is restricted to a vector supermultiplet. The corresponding Lorentz…

High Energy Physics - Theory · Physics 2009-10-30 P. V. Moniz

We establish sharp regularity and Fredholm theorems for the \bar{\partial}_b-Neumann problem on domains satisfying some non-generic geometric conditions. We use these domains to construct explicit examples of bad behaviour of the Kohn…

Complex Variables · Mathematics 2007-05-23 Robert K. Hladky

The Friedman-Lemaitre-Robertson-Walker (FLRW) cosmological models are based on the assumptions of large-scale homogeneity and isotropy of the distribution of matter and energy. They are usually taken to have spatial sections that are simply…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Helio V. Fagundes

Within an effective field theory framework we compute the most general structure of the one-loop corrections to the 4D gauge couplings in one- and two-dimensional orbifold compactifications with non-vanishing constant gauge background…

High Energy Physics - Theory · Physics 2014-11-18 D. M. Ghilencea

While it is usually stated that dimensional regularization (DR) has no direct physical interpretation, consensus has recently grown on the idea that it might be endowed with special physical properties that would provide the mechanism that…

High Energy Physics - Theory · Physics 2022-09-21 Carlo Branchina , Vincenzo Branchina , Filippo Contino , Neda Darvishi

We apply the technique of standard supersymmetric factorization for any q factor ordering in the Wheeler-DeWitt (WDW) equation for barotropic Friedmann-Robertson-Walker (FRW) minisuperspace model, including the cosmological term. The…

Mathematical Physics · Physics 2009-11-10 J. Socorro , M. A. Reyes , F. A. Gelbert

An effective Lagrangian approach based on an extended Einstein-Aether (EA) model is presented and formulated in a generic non flat Fridman-Lemaitre-Robertson-Walker (FLRW) space-time. For a flat FLRW space-time, a Friedmann equation similar…

General Relativity and Quantum Cosmology · Physics 2020-06-10 Alessandro Casalino , Lorenzo Sebastiani , Sergio Zerbini

We introduce a regularization method for mean curvature flow of a submanifold of arbitrary codimension in the Euclidean space, through higher order equations. We prove that the regularized problems converge to the mean curvature flow for…

Analysis of PDEs · Mathematics 2007-05-23 Giovanni Bellettini , Carlo Mantegazza , Matteo Novaga

In this paper, the space-fractional Schr\"{o}dinger equations with singular potentials are studied. Delta-like or even higher-order singularities are allowed. By using the regularising techniques, we introduce a family of 'weakened'…

Analysis of PDEs · Mathematics 2021-02-23 Arshyn Altybay , Michael Ruzhansky , Mohammed Elamine Sebih , Niyaz Tokmagambetov

Massive bigravity models are interesting alternatives to standard cosmology. In most cases, however, these models have been studied for a simplified scenario in which both metrics take homogeneous and isotropic forms…

General Relativity and Quantum Cosmology · Physics 2015-11-18 Henrik Nersisyan , Yashar Akrami , Luca Amendola

Singularities in any physical theory are either remarkable indicators of the unknown underlying fundamental theory, or indicate a change in the description of the physical reality. In General Relativity there are three fundamental kinds of…

General Relativity and Quantum Cosmology · Physics 2023-10-03 Jaume de Haro , Shin'ichi Nojiri , S. D. Odintsov , V. K. Oikonomou , Supriya Pan