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Several approaches to the dynamics of loop quantum gravity involve discretizing the equations of motion. The resulting discrete theories are known to be problematic since the first class algebra of constraints of the continuum theory…

General Relativity and Quantum Cosmology · Physics 2009-01-16 Rodolfo Gambini , Jorge Pullin

Wave propagation problems have many applications in physics and engineering, and the stochastic effects are important in accurately modeling them due to the uncertainty of the media. This paper considers and analyzes a fully discrete finite…

Numerical Analysis · Mathematics 2021-06-30 Yukun Li , Shuonan Wu , Yulong Xing

In this paper, we obtain a quantitative estimate of unique continuation and an observability inequality from an equidistributed set for solutions of the diffusion equation in the whole space RN. This kind of observability indicates that the…

Analysis of PDEs · Mathematics 2021-08-11 Yueliang Duan , Huaiqiang Yu , Can Zhang

We consider a drift-diffusion process with a time-independent and divergence-free random drift that is of white-noise character. We are interested in the critical case of two space dimensions, where one has to impose a small-scale cut-off…

Probability · Mathematics 2025-11-26 Felix Otto , Christian Wagner

Since the pioneering work of James E. Broadwell, discrete velocity models (DVMs) have played a fundamental role in approximating the Boltzmann equation and in the analysis of non-equilibrium gas dynamics. Despite their apparent simplicity,…

Analysis of PDEs · Mathematics 2026-04-21 Koudzo Togbévi Selom Sobah , Amah Séna D'Almeida

While diffusion models excel at generating continuous data such as images, adapting them to discrete tasks has relied on indirect approaches that either operate in continuous embedding spaces or use token masking mechanisms, both of which…

Computer Vision and Pattern Recognition · Computer Science 2025-11-25 Xiao Li , Jiaqi Zhang , Shuxiang Zhang , Tianshui Chen , Liang Lin , Guangrun Wang

In this paper, convergence results on the solutions of a time and space discrete model approximation of the Boltzmann equation for a gas of Maxwellian particles in a bounded domain, obtained by Babovsky and Illner [1989], are extended to…

Numerical Analysis · Mathematics 2014-10-30 C. P. Grünfeld , D. Marinescu

We develop a general technique for proving convergence of repeated quantum interactions to the solution of a quantum stochastic differential equation. The wide applicability of the method is illustrated in a variety of examples. Our main…

Mathematical Physics · Physics 2008-10-20 Luc Bouten , Ramon van Handel

We propose a fully discrete finite volume scheme for the standard Fokker-Planck equation. The space discretization relies on the well-known square-root approximation, which falls into the framework of two-point flux approximations. Our time…

Analysis of PDEs · Mathematics 2024-10-07 Clément Cancès , Léonard Monsaingeon , Andrea Natale

In this paper, we study the relationship between a diffusive model and a non-diffusive model which are both derived from the well-known Keller-Segel model, as a coefficient of diffusion $\varepsilon$ goes to zero. First, we establish the…

Analysis of PDEs · Mathematics 2015-06-11 Hongyun Peng , Huanyao Wen , Changjiang Zhu

This paper investigates the critical quintic wave equation in a 3D bounded domain subject to locally distributed Kelvin-Voigt damping. The study tackles two major mathematical challenges: the severe loss of derivatives induced by the…

Analysis of PDEs · Mathematics 2026-03-10 Marcelo Moreira Cavalcanti , Valeria Neves Domingos Cavalcanti

A rigorous implementation of the Wheeler-Dewitt equations was derived in the context of Loop Quantum Gravity (LQG) and was coined Quantum Spin Dynamics (QSD). The Hamiltonian constraint of QSD was criticised as being too local and to…

General Relativity and Quantum Cosmology · Physics 2021-12-09 Thomas Thiemann , Madhavan Varadarajan

We consider the asymptotic behavior of solutions to the Cauchy problem for the defocusing nonlinear Klein-Gordon equation (NLKG) with exponential nonlinearity in the one spatial dimension with data in the energy space $H^1(\mathbb{R})…

Analysis of PDEs · Mathematics 2021-01-08 Masahiro Ikeda , Takahisa Inui , Mamoru Okamoto

I propose a version of quantum mechanics featuring a discrete and finite number of states that is plausibly a model of the real world. The model is based on standard unitary quantum theory of a closed system with a finite-dimensional…

Quantum Physics · Physics 2023-11-03 Sean M. Carroll

We develop a rigorous treatment of discontinuous stochastic unitary evolution for a system of quantum particles that interacts singularly with quantum "bubbles" at random instants of time. This model of a "cloud chamber" allows to watch and…

Mathematical Physics · Physics 2007-05-23 V. P. Belavkin

The long time behavior of the dynamics of a fast-slow system of ordinary differential equations is examined. The system is derived from a spatial discretization of a Korteweg-de Vries-Burgers type equation, with fast dispersion and slow…

Numerical Analysis · Mathematics 2009-08-20 Zvi Artstein , C. William Gear , Ioannis G. Kevrekidis , Marshall Slemrod , Edriss S. Titi

Diffusion models have achieved huge empirical success in data generation tasks. Recently, some efforts have been made to adapt the framework of diffusion models to discrete state space, providing a more natural approach for modeling…

Machine Learning · Statistics 2024-02-15 Hongrui Chen , Lexing Ying

In the present work we explore the potential of models of the discrete nonlinear Schr\"odinger (DNLS) type to support spatially localized and temporally quasiperiodic solutions on top of a finite background. Such solutions are rigorously…

Pattern Formation and Solitons · Physics 2023-06-16 E. G. Charalampidis , G. James , J. Cuevas-Maraver , D. Hennig , N. I. Karachalios , P. G. Kevrekidis

We study the homogeneous Cauchy-Dirichlet Problem (CDP) for a nonlinear and nonlocal diffusion equation of singular type of the form $\partial_t u =-\mathcal{L} u^m$ posed on a bounded Euclidean domain $\Omega\subset\mathbb{R}^N$ with…

Analysis of PDEs · Mathematics 2022-08-01 Matteo Bonforte , Peio Ibarrondo , Mikel Ispizua

Quantum computing has demonstrated potential for solving complex optimization problems; however, its application to spatial regionalization remains underexplored. Spatial contiguity, a fundamental constraint requiring spatial entities to…

Distributed, Parallel, and Cluster Computing · Computer Science 2025-06-03 Yunhan Chang , Amr Magdy , Federico M. Spedalieri