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We realize a cold-atom system to quantitatively test relational constructions of time. A well-isolated atomic Bose-Einstein condensate evolves in a conservative trap that is partitioned by a thin optical barrier into an observed and…

General Relativity and Quantum Cosmology · Physics 2026-03-17 Giovanni Barontini

We prove optimal estimates for the decay in time of solutions to a rather general class of non-local in time subdiffusion equations in $\mathbb{R}^d$. An important special case is the time-fractional diffusion equation, which has seen much…

Analysis of PDEs · Mathematics 2014-03-10 Jukka Kemppainen , Juhana Siljander , Vicente Vergara , Rico Zacher

We study the dynamics of entropy in a time dependent potential and explore how disorder influences this entropy flow. We show that disorder can trap entropy at the edge of the atomic cloud enabling a novel cooling method. We demonstrate the…

Quantum Gases · Physics 2017-02-28 F. Nur Ünal , Erich J. Mueller

Cloud droplets containing ice-nucleating particles (INPs) may freeze at temperatures above the homogeneous freezing threshold temperature. This process, referred to as immersion freezing, is one of the modulators of aerosol-cloud…

The homogeneous bosonic Nordheim equation is a kinetic equation describing the dynamics of the distribution of particles in the space of moments for a homogeneous, weakly interacting, quantum gas of bosons. We show the existence of…

Mathematical Physics · Physics 2013-12-31 M. l Escobedo , J. J. L. Velázquez

The nonlinear boson diffusion equation is taken as a basis to account for the fast thermalization of gluons in the initial stages of relativistic heavy-ion collisions. For constant drift and diffusion coefficients with schematic initial…

High Energy Physics - Phenomenology · Physics 2025-11-25 J. Rössler , G. Wolschin

We study the diffusion equation with an appropriate change of variables. This equation is in general a partial differential equation (PDE). With the self-similar and related Ansat\"atze we transform the PDE of diffusion to an ordinary…

Classical Physics · Physics 2023-04-14 Imre Ferenc Barna , László Mátyás

In this paper, we numerically address the inverse problem of identifying a time-dependent coefficient in the time-fractional diffusion equation. An a priori estimate is established to ensure uniqueness and stability of the solution. A fully…

Numerical Analysis · Mathematics 2026-01-27 Arshyn Altybay

We present a series of results focused on the decay in time of solutions of classical and anomalous diffusive equations in a bounded domain. The size of the solution is measured in a Lebesgue space, and the setting comprises time-fractional…

Analysis of PDEs · Mathematics 2019-08-09 Elisa Affili , Serena Dipierro , Enrico Valdinoci

We study a class of degenerate convection diffusion equations with a fractional nonlinear diffusion term. These equations are natural generalizations of anomalous diffusion equations, fractional conservations laws, local convection…

Analysis of PDEs · Mathematics 2011-07-28 Simone Cifani , Espen R. Jakobsen

We analyze the stochastic thermodynamics of systems with continuous space of states. The evolution equation, the rate of entropy production, and other results are obtained by a continuous time limit of a discrete time formulation. We point…

Statistical Mechanics · Physics 2020-08-27 Mário J. de Oliveira

The hydrodynamic equation governing the homogeneous time evolution of the temperature in a model of confined granular gas is studied by means of the Enskog equation. The existence of a normal solution of the kinetic equation is assumed as a…

Statistical Mechanics · Physics 2015-06-18 J. Javier Brey , P. Maynar , M. I. García de Soria , V. Buzón

This paper discusses finite time extinction for a perturbed fast diffusion equation with dynamic boundary conditions. The fast diffusion equation has the characteristic property of decay, such as the solution decays to zero in a finite…

Analysis of PDEs · Mathematics 2020-09-03 Takeshi Fukao

In this paper we consider the problem of simultaneously determining the time-dependent thermal diffusivity and the temperature distribution in one-dimensional heat equation in the case of nonlocal boundary and integral overdetermination…

Analysis of PDEs · Mathematics 2015-03-17 Mansur I. Ismailov , Fatma Kanca

We study the condensate phase dynamics in a low-temperature equilibrium gas of weakly interacting bosons, harmonically trapped and isolated from the environment. We find that at long times, much longer than the collision time between…

Quantum Gases · Physics 2019-04-22 Yvan Castin , Alice Sinatra

We use the time-dependent variational of Balian and Veneroni to derive a set of equations governing the dynamics of a trapped Bose gas at finite temperature. We show that this dynamics generalizes the Gross-Pitaevskii equations in that it…

Other Condensed Matter · Physics 2009-11-11 M. Benarous

We investigate the time evolution of the Boltzmann entropy of a dilute gas of N particles, N>>1, as it undergoes a free expansion doubling its volume. The microstate of the system, a point in the 4N dimensional phase space, changes in time…

Statistical Mechanics · Physics 2024-10-08 P. L. Garrido , S. Goldstein , D. A. Huse , J. L. Lebowitz

We consider solutions to the Kac master equation for initial conditions where $N$ particles are in a thermal equilibrium and $M\le N$ particles are out of equilibrium. We show that such solutions have exponential decay in entropy relative…

Mathematical Physics · Physics 2018-10-17 Federico Bonetto , Alissa Geisinger , Michael Loss , Tobias Ried

In this paper we use a similarity transformation connecting some families of Nonlinear Schrodinger equations with time-varying coefficients with the autonomous cubic nonlinear Schrodinger equation. This transformation allows one to apply…

Pattern Formation and Solitons · Physics 2009-11-11 Victor M. Perez-Garcia , Pedro J. Torres , Vladimir V. Konotop

In this paper the determination of material properties such as Sieverts' constant (solubility) and diffusivity (transport rate) via so-called gas release experiments is discussed. In order to simulate the time-dependent hydrogen fluxes and…

Applied Physics · Physics 2021-04-16 Marvin R. Schulz , Kaori Nagatou , Axel von der Weth , Frederik Arbeiter , Volker Pasler