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We study the coherent propagation and incoherent diffusion of in-plane elastic waves in a two dimensional continuum populated by many, randomly placed and oriented, edge dislocations. Because of the Peierls-Nabarro force the dislocations…

Materials Science · Physics 2020-12-02 Dmitry Churochkin , Fernando Lund

Several challenging problem in clustering, partitioning and imaging have traditionally been solved using the "spectral technique". These problems include the normalized cut problem, the graph expander ratio problem, the Cheeger constant…

Optimization and Control · Mathematics 2016-10-14 Dorit S. Hochbaum

Time-dependent density-functional theory (TDDFT) is a computationally efficient first-principles approach for calculating optical spectra in insulators and semiconductors, including excitonic effects. We show how exciton wave functions can…

Materials Science · Physics 2020-12-29 Jared R. Williams , Nicolas Tancogne-Dejean , Carsten A. Ullrich

The ill-posed problem of phase retrieval in optics, using one or more intensity measurements, has a multitude of applications using electromagnetic or matter waves. Many phase retrieval algorithms are computed on pixel arrays using discrete…

Image and Video Processing · Electrical Eng. & Systems 2022-09-21 J. A. Pollock , K. S. Morgan , L. C. P. Croton , M. K. Croughan , G. Ruben , N. Yagi , H. Sekiguchi , M. J. Kitchen

Projected Hartree-Fock theory (PHF) has a long history in quantum chemistry. PHF is here understood as the variational determination of an N-electron broken symmetry Slater determinant that minimizes the energy of a projected state with the…

Strongly Correlated Electrons · Physics 2013-06-28 Carlos A. Jimenez-Hoyos , Thomas M. Henderson , Takashi Tsuchimochi , Gustavo E. Scuseria

In this article we consider the approximation of a variable coefficient (two-sided) fractional diffusion equation (FDE), having unknown $u$. By introducing an intermediate unknown, $q$, the variable coefficient FDE is rewritten as a lower…

Numerical Analysis · Mathematics 2018-10-31 Xiangcheng Zheng , V. J. Ervin , Hong Wang

Nonlinear time fractional partial differential equations are widely used in modeling and simulations. In many applications, there are high contrast changes in media properties. For solving these problems, one often uses coarse spatial grid…

Numerical Analysis · Mathematics 2022-07-13 Wenyuan Li , Anatoly Alikhanov , Yalchin Efendiev , Wing Tat Leung

We consider the scattering of linear waves in two dimensions by a rectangular region at the junction of four waveguides. A solution to the frequency domain problem is obtained by exploiting reflective symmetry to reduce the full problem to…

Mathematical Physics · Physics 2024-11-28 Afnan A. Aldosri , Michael H. Meylan , Ben Wilks

We describe a method to probe the spectral fluctuations of a transition over broad ranges of frequencies and timescales with the high spectral resolution of Fourier spectroscopy, and a temporal resolution as high as the excited state…

We present an algorithm that uses the distribution of photon arrival times to distinguish speckles from incoherent sources, like planets and disks, in high contrast images. Using simulated data, we show that our approach can overcome the…

Instrumentation and Methods for Astrophysics · Physics 2019-10-09 Alex B. Walter , Clinton Bockstiegel , Timothy D. Brandt , Benjamin A. Mazin

We propose and explore the potential of a method to extract high signal-to-noise (S/N) integrated spectra related to physical and/or morphological regions on a 2-dimensional field using Integral Field Spectroscopy (IFS) observations by…

Instrumentation and Methods for Astrophysics · Physics 2015-06-03 F. F. Rosales-Ortega , S. Arribas , L. Colina

Diffusion models achieve state-of-the-art performance in various generation tasks. However, their theoretical foundations fall far behind. This paper studies score approximation, estimation, and distribution recovery of diffusion models,…

Machine Learning · Computer Science 2023-02-15 Minshuo Chen , Kaixuan Huang , Tuo Zhao , Mengdi Wang

Diffusion models have emerged as a powerful tool for point cloud generation. A key component that drives the impressive performance for generating high-quality samples from noise is iteratively denoise for thousands of steps. While…

Computer Vision and Pattern Recognition · Computer Science 2022-12-06 Lemeng Wu , Dilin Wang , Chengyue Gong , Xingchao Liu , Yunyang Xiong , Rakesh Ranjan , Raghuraman Krishnamoorthi , Vikas Chandra , Qiang Liu

The optical theorem is an important tool for scattering analysis in acoustics, electromagnetism, and quantum mechanics. We derive an extended version of the optical theorem for the scattering of elastic waves by a spherical inclusion…

Classical Physics · Physics 2017-04-26 J. P. Leao-Neto , J. H. Lopes , G. T. Silva

We present a new random walk for uniformly sampling high-dimensional convex bodies. It achieves state-of-the-art runtime complexity with stronger guarantees on the output than previously known, namely in R\'enyi divergence (which implies…

Data Structures and Algorithms · Computer Science 2026-03-23 Yunbum Kook , Santosh S. Vempala , Matthew S. Zhang

Generative diffusion models have emerged as a powerful tool for high-quality image synthesis, yet their iterative nature demands significant computational resources. This paper proposes an efficient time step sampling method based on an…

Computer Vision and Pattern Recognition · Computer Science 2026-05-12 Haeil Lee , Hansang Lee , Seoyeon Gye , Junmo Kim

Optimal extraction is a key step in processing the raw images of spectra as registered by two-dimensional detector arrays to a one-dimensional format. Previously reported algorithms reconstruct models for a mean one-dimensional spatial…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 M. Zechmeister , G. Anglada-Escudé , A. Reiners

Space-time (ST) wave packets are coherent pulsed beams that propagate diffraction-free and dispersion-free by virtue of tight correlations introduced between their spatial and temporal spectral degrees of freedom. Less is known of the…

Tracer diffusion and hydrodynamic dispersion in two-dimensional fractures with self-affine roughness is studied by analytic and numerical methods. Numerical simulations were performed via the lattice-Boltzmann approach, using a new boundary…

Statistical Mechanics · Physics 2016-08-31 German Drazer , Joel Koplik

Diffusion models have emerged as a powerful method in various applications. However, their application to Short-Term Electricity Load Forecasting (STELF) -- a typical scenario in energy systems -- remains largely unexplored. Considering the…

Machine Learning · Computer Science 2026-01-13 Qi Dong , Rubing Huang , Ling Zhou , Dave Towey , Jinyu Tian , Jianzhou Wang
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