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We consider the generalized time-dependent Schr\"odinger equation on the half-axis and a broad family of finite-difference schemes with the discrete transparent boundary conditions (TBCs) to solve it. We first rewrite the discrete TBCs in a…

Numerical Analysis · Mathematics 2026-01-05 Alexander Zlotnik , Ilya Zlotnik

We study the nonlinear Schr\"odinger equation on the half-line with a boundary condition that involves time derivative. This boundary condition was presented by Zambon [J. High Energ. Phys. 2014 (2014) 36]. We establish the integrability of…

Exactly Solvable and Integrable Systems · Physics 2020-08-11 Baoqiang Xia

The relativistic Boltzmann equation in bounded domains has been widely used in physics and engineering, for example, Tokamak devices in fusion reactors.In spite of its importance, there has, to the best of our knowledge, been no…

Analysis of PDEs · Mathematics 2023-08-30 Yong Wang , Changguo Xiao

We analyze the d'Alembert equation in the Goedel-type spacetimes with spherical and Lobachevsky sections (with sufficiently rapid rotation). By separating the $t$ and $x_3$ dependence we reduce the problem to a group-theoretical one. In the…

General Relativity and Quantum Cosmology · Physics 2012-01-25 P. Marecki

We consider in this paper the mathematical and numerical modelling of reflective boundary conditions (BC) associated to Boltzmann - Poisson systems, including diffusive reflection in addition to specularity, in the context of electron…

Numerical Analysis · Mathematics 2018-03-19 Jose A. Morales Escalante , Irene M. Gamba

We establish the global-wellposedness and stability of the Boltzmann equation with the specular reflection boundary condition in general smooth convex domains when an initial datum is close to the Maxwellian with or without a small external…

Analysis of PDEs · Mathematics 2018-01-23 Chanwoo Kim , Donghyun Lee

A basic question about the existence and stability of the Boltzmann equation in general non-convex domain with the specular reflection boundary condition has been widely open. In this paper, we consider cylindrical domains whose cross…

Analysis of PDEs · Mathematics 2018-05-01 Chanwoo Kim , Donghyun Lee

We formulate a set of conditions under which dynamics of a time-dependent quantum Hamiltonian are integrable. The main requirement is the existence of a nonabelian gauge field with zero curvature in the space of system parameters. Known…

Quantum Physics · Physics 2018-05-16 Nikolai A. Sinitsyn , Emil A. Yuzbashyan , Vladimir Y. Chernyak , Aniket Patra , Chen Sun

Diffraction in time of a particle confined in a box which its walls are removed suddenly at $t=0$ is studied. The solution of the time-dependent Schr\"{o}dinger equation is discussed analytically and numerically for various initial…

Quantum Physics · Physics 2011-12-30 S. V. Mousavi

In this paper, we consider the Cauchy problem for the relativistic Boltzmann equation with near vacuum initial data where the distribution function depends on the time, the position and the impulsion. The collision kernel considered here is…

General Relativity and Quantum Cosmology · Physics 2016-09-20 Etienne Takou , Fidele L. Ciake Ciake

We introduce several new notions of (sectional) curvature bounds for Lorentzian pre-length spaces: On the one hand, we provide convexity/concavity conditions for the (modified) time separation function, and, on the other hand, we study…

Differential Geometry · Mathematics 2026-01-14 Tobias Beran , Michael Kunzinger , Felix Rott

We investigate the fractional diffusion limit of a Linear Boltzmann equation with heavy-tailed velocity equilibrium in a half-space with Maxwell boundary conditions. We derive a new confined version of the fractional Laplacian and show…

Analysis of PDEs · Mathematics 2022-10-06 Ludovic Cesbron

We obtain exact solutions to the class of parabolic partial differential equations of arbitrary dimensionality and with arbitrary potentials. The solutions are presented in a compact-form: as explicit mathematical expressions consisting of…

Mathematical Physics · Physics 2023-08-29 Ivan Gonoskov

A simplified relativistic kinetic theory for gases with internal degrees of freedom, based on a BGK-type collision term, is considered. First the Boltzmann equation is rewritten in tetrad form and then thermal coefficients are determined to…

General Relativity and Quantum Cosmology · Physics 2026-04-13 Philip Semrén , Michael Bradley , João M. S. Oliveira , M. Piedade Machado Ramos

This paper discusses the possibility of constructing time-independent solutions to the collisionless Boltzmann equation which depend on quantities other than global isolating integrals such as energy and angular momentum. The key point is…

Astrophysics · Physics 2009-10-30 Henry E. Kandrup

The question about the appearance of time in the semiclassical limit of quantum gravity continues to be discussed in the literature. It is believed that a temporal Schrodinger equation for matter fields on the background of a classical…

General Relativity and Quantum Cosmology · Physics 2025-07-24 R. I. Ayala Oña , M. B. Kalmykov , D. P. Kislyakova , T. P. Shestakova

We use a careful treatment of time-dependent wave-mechanical scattering to determine the conditions under which a dilute, non-degenerate quantum gas can obey a Boltzmann equation. If the gas possesses weak long-range coherence, such as may…

Quantum Gases · Physics 2019-05-08 L. Rico-Pérez , J. R. Anglin

The Boltzmann equation is a fundamental equation in kinetic theory that describes the motion of rarefied gases. In this study, we examine the Boltzmann equation within a $C^1$ bounded domain, subject to a large external potential $\Phi(x)$…

Analysis of PDEs · Mathematics 2025-06-10 Jong-in Kim , Donghyun Lee

The Boltzmann equation is the traditional framework in which one extends the time-dependent mean field classical description of a many-body system to include the effect of particle-particle collisions in an approximate manner. A…

Nuclear Theory · Physics 2022-02-10 A. Bulgac

We consider the Boltzmann equation with external fields in strictly convex domains with the specular reflection boundary condition. We construct classical $C^1$ solutions away from the grazing set under the assumption that the external…

Analysis of PDEs · Mathematics 2020-06-24 Yunbai Cao