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Light propagation in a medium made of densely packed dielectric spheres is investigated by using a rigorous diffraction theory. It is shown that a substantial suppression of the local density of states occurs in spectral domains where the…

Optics · Physics 2015-05-13 Carsten Rockstuhl , Falk Lederer

We study the transport properties of a system of active particles moving at constant speed in an heterogeneous two-dimensional space. The spatial heterogeneity is modeled by a random distribution of obstacles, which the active particles…

Biological Physics · Physics 2013-10-23 Oleksandr Chepizhko , Fernando Peruani

An implicit Euler finite-volume scheme for general cross-diffusion systems with volume-filling constraints is proposed and analyzed. The diffusion matrix may be nonsymmetric and not positive semidefinite, but the diffusion system is assumed…

Numerical Analysis · Mathematics 2021-05-13 Ansgar Jüngel , Antoine Zurek

Generative diffusion models have achieved remarkable success in producing high-quality images. However, these models typically operate in continuous intensity spaces, diffusing independently across pixels and color channels. As a result,…

Graphics · Computer Science 2025-05-20 Javier E. Santos , Agnese Marcato , Roman Colman , Nicholas Lubbers , Yen Ting Lin

Here we develop a general theory of mode transformation (diffraction) at the flat transverse boundary between cold magnetized electron plasma and isotropic vacuum-like medium inside a circular waveguide. The obtained results can be also…

Plasma Physics · Physics 2021-05-03 Sergey N. Galyamin

We investigate the emergence of three-dimensional behavior in a reduced-dimension Bose-Einstein condensate trapped by a highly anisotropic potential. We handle the problem analytically by performing a perturbative Schmidt decomposition of…

Quantum Physics · Physics 2015-05-28 Alexandre B. Tacla , Carlton M. Caves

Using the FDTD method, we investigate the electromagnetic propagation in two-dimensional photonic crystals, formed by parallel air cylinders in a dielectric medium. The corresponding frequency band structure is computed using the standard…

Materials Science · Physics 2009-11-10 Hung-Ta Chien , Hui-Ting Tang , Chao-Hsien Kuo , Chii-Chang Chen , Zhen Ye

Let $E$ be a complete, separable metric space and $A$ be an operator on $C_b(E)$. We give an abstract definition of viscosity sub/supersolution of the resolvent equation $\lambda u-Au=h$ and show that, if the comparison principle holds,…

Probability · Mathematics 2015-11-19 Cristina Costantini , Thomas G. Kurtz

We study the coherence properties of optical vortices stored in atomic ensembles. In the presence of thermal diffusion, the topological nature of stored optical vortices is found not to guarantee slow decoherence. Instead the stored vortex…

Quantum Physics · Physics 2009-11-13 T. Wang , L. Zhao , L. Jiang , S. F. Yelin

We rigorously derive non-equilibrium space-time fluctuation for the particle density of a system of reflected diffusions in bounded Lipschitz domains in $\mathbb R^d$. The particles are independent and are killed by a time-dependent…

Probability · Mathematics 2021-01-12 Zhen-Qing Chen , Wai-Tong Louis Fan

We present a new a-priori estimate for discrete coagulation-fragmentation systems with size-dependent diffusion within a bounded, regular domain confined by homogeneous Neumann boundary conditions. Following from a duality argument, this…

Analysis of PDEs · Mathematics 2010-11-23 José A. Cañizo , Laurent Desvillettes , Klemens Fellner

We succeed in writing 2-dimensional conformally invariant non-linear elliptic PDE (harmonic map equation, prescribed mean curvature equations...etc) in divergence form. This divergence free quantities generalize to target manifolds without…

Analysis of PDEs · Mathematics 2007-05-23 Riviere Tristan

We explore various models for the pattern forming instability in a laser-driven cloud of cold two-level atoms with a plane feedback mirror. Focus is on the combined treatment of nonlinear propagation in a diffractively thick medium and the…

Atomic Physics · Physics 2016-06-16 W. J. Firth , I. Krešić , G. Labeyrie , A. Camara , P. Gomes , T. Ackemann

A systematic analysis of the discrete conservation properties of non-dissipative, central-difference approximations of the compressible Navier-Stokes equations is reported. A general triple splitting of the nonlinear convective terms is…

Fluid Dynamics · Physics 2019-02-20 Gennaro Coppola , Francesco Capuano , Sergio Pirozzoli , Luigi de Luca

The exact solution of a diffusion$-$reaction model for the trapping and annihilation of positrons in small extended spherical defects (clusters, voids, small precipitates) with competitive rate-limited trapping in vacancy-type point defects…

Materials Science · Physics 2019-04-24 Roland Würschum , Laura Resch , Gregor Klinser

Using pointwise semigroup techniques, we establish sharp rates of decay in space and time of a perturbed reaction diffusion front to its time-asymptotic limit. This recovers results of Sattinger, Henry and others of time-exponential…

Analysis of PDEs · Mathematics 2019-01-15 Yingwei Li

We introduce a Darcy-scale model to describe compressible multi-component flow in a fully saturated porous medium. In order to capture cross-diffusive effects between the different species correctly, we make use of the Maxwell--Stefan…

Analysis of PDEs · Mathematics 2020-12-02 Lukas Ostrowski , Christian Rohde

The dynamics of various optically controlled non-equilibrium phenomena in the condensed phase are studied using the Liouville equation. We study a projection of the same in a slow moving coordinate, identified as the Reaction Coordinate…

Quantum Physics · Physics 2021-12-14 Sagnik Ghosh , Alok Samanta , Swapan K. Ghosh

Metasurfaces enable powerful control of electromagnetic waves using subwavelength planar structures, but their deeply subwavelength periodicity typically suppresses propagating diffraction orders, which limits the number of available…

Optics · Physics 2026-05-14 Karim Achouri

We consider a semi-infinite dielectric with multiple spatially dispersive resonances in the susceptibility. The effect of the boundary is described by an arbitrary reflection coefficient for polarization waves in the material at the…

Optics · Physics 2017-05-10 R. J. Churchill , T. G. Philbin