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The optical reflection coefficient of a dielectric medium moving uniformly in the plane spanned by its surface is rigorously calculated using classical electrodynamics and special relativity, and expressed in the Fourier domain, as a…

This paper presents a fast spectral unmixing algorithm based on Dykstra's alternating projection. The proposed algorithm formulates the fully constrained least squares optimization problem associated with the spectral unmixing task as an…

Computer Vision and Pattern Recognition · Computer Science 2015-05-08 Qi Wei , Jose Bioucas-Dias , Nicolas Dobigeon , Jean-Yves Tourneret

We generalize the short-time Fourier transform (STFT) formalism for radial velocity extraction to cases where the underlying spectral components are unknown. The method factorizes a spectroscopic time series into principal spectra and…

Earth and Planetary Astrophysics · Physics 2026-02-17 Sahar Shahaf , Barak Zackay

Many common methods for data analysis rely on linear algebra. We provide new results connecting data analysis error to numerical accuracy, which leads to the first meaningful stopping criterion for two way spectral partitioning. More…

Numerical Analysis · Computer Science 2016-02-03 James P. Fairbanks , Geoffrey D. Sanders , David A. Bader

We present a theory of vibrational modulation of two-dimensional coherent Fourier transformed electronic spectra. Based on an expansion of the system's energy gap correlation function in terms of Huang-Rhys factors, we explain the…

Adapting a pretrained diffusion model to new objectives at inference time remains an open problem in generative modeling. Existing steering methods suffer from inaccurate value estimation, especially at high noise levels, which biases…

Machine Learning · Computer Science 2025-06-27 Vineet Jain , Kusha Sareen , Mohammad Pedramfar , Siamak Ravanbakhsh

We present a method for accurately computing transition probabilities in one-dimensional photoionization problems. Our approach involves solving the time-dependent Schr\"odinger equation and projecting its solution onto scattering states…

Computational Physics · Physics 2025-04-10 Martín Barlari , Diego G. Arbó , María Silvia Gravielle , Darío M. Mitnik

Nuclear Magnetic Resonance (NMR) spectrometry uses electro-frequency pulses to probe the resonance of a compound's nucleus, which is then analyzed to determine its structure. The acquisition time of high-resolution NMR spectra remains a…

Fourier-domain Difference Map (FDM) for phase retrieval with two oversampled coded diffraction patterns are proposed. FDM is a 3-parameter family of fixed point algorithms including Fourier-domain Hybrid-Projection-Reflection (FHPR) and…

Data Analysis, Statistics and Probability · Physics 2016-03-09 Albert Fannjiang

Diffusion models have become a leading paradigm for image super-resolution (SR), but existing methods struggle to guarantee both the high-frequency perceptual quality and the low-frequency structural fidelity of generated images. Although…

Computer Vision and Pattern Recognition · Computer Science 2026-04-14 Hexin Zhang , Dong Li , Jie Huang , Bingzhou Wang , Xueyang Fu , Zhengjun Zha

We show how Stokes' Theorem, in the fashion of the Generalised Cauchy Formula, can be applied for computing double-cut integrals of one-loop amplitudes analytically. It implies the evaluation of phase-space integrals of rational functions…

High Energy Physics - Phenomenology · Physics 2009-09-11 Pierpaolo Mastrolia

A three-level explicit time-split MacCormack scheme is proposed for solving the two-dimensional nonlinear reaction-diffusion equations. The computational cost is reduced thank to the splitting and the explicit MacCormack scheme. Under the…

Numerical Analysis · Mathematics 2020-12-02 Eric Ngondiep

Traditional full-field optical coherence tomography (FF-OCT) is effective for rapid cross-sectional imaging but often suffers from incoherent signals due to imbalanced light intensities between the sample and reference arms. While the…

Optics · Physics 2024-10-17 Youlong Fan , Qingye Hu , Zhongping Wang , Zengming Zhang , Xiantao Wei

Based on the classical Lorentz model of the index of refraction, a new method is presented for the extraction of the complex index of refraction from the extinction efficiency of homogeneous and layered dielectric spheres that…

Optics · Physics 2022-06-28 Kalpa de Silva , Proity Akbar , Reinhold Blümel

Spectral computed tomography (CT) with photon-counting detectors holds immense potential for material discrimination and tissue characterization. However, under ultra-low-dose conditions, the sharply degraded signal-to-noise ratio (SNR) in…

Computer Vision and Pattern Recognition · Computer Science 2026-02-10 Peng Peng , Xinrui Zhang , Junlin Wang , Lei Li , Shaoyu Wang , Qiegen Liu

This paper deals with the problem of efficient sampling from a stochastic differential equation, given the drift function and the diffusion matrix. The proposed approach leverages a recent model for probabilities \cite{rudi2021psd} (the…

Machine Learning · Statistics 2023-05-25 Anant Raj , Umut Şimşekli , Alessandro Rudi

In this paper, we investigate direct and inverse source problems for the diffusion equation with two-term generalized fractional derivative (Hilfer derivative) in a rectangular domain. Using spectral expansion method, we derive two-term…

Analysis of PDEs · Mathematics 2019-04-05 M. S. Salakhitdinov , E. T. Karimov

Molecular electronic spectra can be represented in the time domain as auto-correlation functions of the initial vibrational wavepacket. We present a derivation of the harmonic vibrational auto-correlation function that is valid for both…

Chemical Physics · Physics 2022-10-05 P. Bryan Changala , Nadav Genossar , Joshua H. Baraban

Over the last three decades numerous numerical methods for solving the time-dependent Schr\"{o}dinger equation within the single-active electron approximation have been developed for studying ionization of atomic targets exposed to an…

Atomic Physics · Physics 2020-08-12 B. Fetić , W. Becker , D. B. Milošević

Dye experimentation is a widely used method in experimental fluid mechanics for flow analysis or for the study of the transport of particles within a fluid. This technique is particularly useful in biomedical diagnostic applications ranging…

Fluid Dynamics · Physics 2023-09-25 Faisal Amlani , Heng Wei , Niema M. Pahlevan