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Related papers: On Multiple Frequency Power Density Measurements

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We prove that any distribution $q$ satisfying the equation $\nabla q=\div{\bf f}$ for some tensor ${\bf f}=(f^i_j), f^i_j\in h^r(U)$ ($1\leq r<\infty$) -the {\it local Hardy space}, $q$ is in $h^r$, and is locally represented by the sum of…

Analysis of PDEs · Mathematics 2008-07-25 Nirmalendu Chaudhuri , Aram L. Karakhanyan

For a smooth strictly plurisubharmonic function $u$ on a open set $\Omega\subset\mathbb{C}^{n}$ and $F$ a $C^{1}$ nondecreasing function on $\mathbf{R}^{*}_{+}$, we investigate the complex partial differential equations…

Differential Geometry · Mathematics 2017-07-11 Said Asserda

This paper establishes a comprehensive mathematical framework connecting optical physics equations to generative models, demonstrating how light propagation dynamics inspire powerful artificial intelligence approaches. We analyze six…

Optics · Physics 2025-06-06 Amirreza Ahmadnejad , Somayyeh Koohi

Construction of an optical quantum computer (OQC) is finished by implementing all necessary ingredients with light (photon). There is, however, one more hurdle to clear. It is scalability, which is easily lost when accommodating many qubits…

Quantum Physics · Physics 2010-09-28 T. Asaba , S. Fukatsu

We derive the equation of matter density perturbations on sub-horizon scales for a general Lagrangian density f(R, phi, X) that is a function of a Ricci scalar R, a scalar field phi and a kinetic term X=-(nabla phi)^2/2. This is useful to…

Astrophysics · Physics 2008-12-18 Shinji Tsujikawa

Given a bounded smooth domain $\Omega$ in $\mathbb{R}^2$, we study the following anisotropic elliptic problem $$ \begin{cases} -\nabla\big(a(x)\nabla \upsilon\big)= a(x)\big[e^{\upsilon}-s\phi_1-4\pi\alpha\delta_q-h(x)\big]\,\,\,\,…

Analysis of PDEs · Mathematics 2024-04-16 Yibin Zhang

Inverse scattering problems without the phase information arise in imaging of nanostructures whose sizes are hundreds of nanometers as well as in imaging of biological cells. The governing equation is the 3-d generalized Helmholtz equation…

Analysis of PDEs · Mathematics 2015-10-05 Michael V. Klibanov , Loc H. Nguyen , Kejia Pan

We consider the time-harmonic Maxwell equations at a nonzero wavenumber $k\in\mathbb{C}$ on a bounded and simply connected Lipschitz domain $\Omega$ with an analytic boundary $\Gamma$, on which we impose impedance boundary conditions. We…

Analysis of PDEs · Mathematics 2026-03-18 Jens Markus Melenk , David Wörgötter

The Helmholtz equation can be written as coupled equations for the amplitude and phase. By considering spatial phase distributions corresponding to reflectionless wave propagation in the plane and solving for the amplitude in terms of this…

Optics · Physics 2018-05-23 Chris King , Simon Horsley , Thomas Philbin

We develop arguments on convexity and minimization of energy functionals on Orlicz-Sobolev spaces to investigate existence of solution to the equation $\displaystyle -\mbox{div} (\phi(|\nabla u|) \nabla u) = f(x,u) + h \mbox{in} \Omega$…

Analysis of PDEs · Mathematics 2013-10-23 J. V. Goncalves , M. L. M. Carvalho

In this note we construct smooth bounded domains $\Omega \subset \mathbb R^2$, other than disks, for which the overdetermined problem $$ \left\{ \begin{alignedat}{2} \Delta u + \lambda u &= 0 &\qquad& \text{ in } \Omega, \newline u &= b…

Analysis of PDEs · Mathematics 2025-09-03 Miles H. Wheeler

Einstein field equations under spherically symmetric space-times are considered here in connection to dark energy investigation. A set of solutions are obtained for a kinematical $\Lambda$ model, viz., $\Lambda \sim (\dot a/a)^2$ without…

General Relativity and Quantum Cosmology · Physics 2009-05-12 Utpal Mukhopadhyay , P. C. Ray , Saibal Ray , S. B. Datta Choudhury

We consider inverse problems for the Einstein equation with a time-depending metric on a 4-dimensional globally hyperbolic Lorentzian manifold $(M,g)$. We formulate the concept of active measurements for relativistic models. We do this by…

Analysis of PDEs · Mathematics 2013-05-30 Yaroslav Kurylev , Matti Lassas , Gunther Uhlmann

Fast and accurate resolution of electromagnetic problems via the \ac{BEM} is oftentimes challenged by conditioning issues occurring in three distinct regimes: (i) when the frequency decreases and the discretization density remains constant,…

Computational Physics · Physics 2020-04-22 Alexandre Dély , Adrien Merlini , Simon B. Adrian , Francesco P. Andriulli

In this paper, we consider the following nonlinear parabolic equation with non-coercive terms in \(R^N\) space \[ \dfrac{\partial u}{\partial t} -\nabla \cdot (a(x,t,u,\nabla u)+ \Phi(x,t,\nabla u))=f, \text{ in }\Omega \times (0,T). \]…

Analysis of PDEs · Mathematics 2026-05-05 Shijun Li , Shujing Li , Shaopeng Xu

Let $\Omega \subset \mathbb{R}^{N}$ be a smooth bounded domain, $H$ a Caratheodory function defined in $\Omega \times \mathbb{R\times R}^{N},$ and $\mu $ a bounded Radon measure in $\Omega .$ We study the problem% \begin{equation*}…

Analysis of PDEs · Mathematics 2013-02-14 Marie-Françoise Bidaut-Véron , Marta Garcia-Huidobro , Laurent Veron

The paper concerns with the decay property of solutions to the initial-boundary value problem of the semilinear heat equation $\partial_tu-\Delta u+u^p=0$ in exterior domains $\Omega$ in $\mathbb{R}^N$ ($N\geq 2$). The problem for the…

Analysis of PDEs · Mathematics 2025-03-27 Ahmad Fino , Motohiro Sobajima

The self-consistent inclusion of plasma effects in opacity calculations is a significant modeling challenge. As density increases, such effects can no longer be treated perturbatively. Building on a recently published model that addresses…

Plasma Physics · Physics 2024-10-08 C. E. Starrett , C. J. Fontes , H. B. Tran Tan , J. M. Kasper , J. R. White

The calculation of the optical properties of hot dense plasmas with a model that has self-consistent plasma physics is a grand challenge for high energy density science. Here we exploit a recently developed electronic structure model that…

Plasma Physics · Physics 2022-01-07 Nathaniel R. Shaffer , Charles E. Starrett

We prove a quantitative inhomogeneous Hopf-Oleinik lemma for viscosity solutions of $$|\nabla u|^{\alpha}F(D^{2}u)=f $$ and, more generally, for viscosity supersolutions of $|\nabla u|^{\alpha}\,{M}^-_{\lambda,\Lambda}(D^{2}u)\le f$. The…

Analysis of PDEs · Mathematics 2025-12-22 Davide Giovagnoli , Enzo Maria Merlino , Diego Moreira