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This paper presents a novel Bayesian approach for hyperspectral image unmixing. The observed pixels are modeled by a linear combination of material signatures weighted by their corresponding abundances. A spike-and-slab abundance prior is…

Applications · Statistics 2022-05-04 Zeng Li , Yoann Altmann , Jie Chen , Stephen Mclaughlin , Susanto Rahardja

Exact free energy minimization is a convex optimization problem that is usually approximated with stochastic sampling methods. Deterministic approximations have been less successful because many desirable properties have been difficult to…

Computational Physics · Physics 2016-03-17 Jonathan E. Moussa

Pulsar dynamic spectra exhibit high visibility fringes arising from interference between scattered radio waves. These fringes may be random or highly ordered patterns, depending on the nature of the scattering or refraction. Here we…

Astrophysics · Physics 2009-11-10 Mark Walker , Dan Stinebring

We study random points on the real line generated by the eigenvalues in unitary invariant random matrix ensembles or by more general repulsive particle systems. As the number of points tends to infinity, we prove convergence of the…

Probability · Mathematics 2015-11-11 Kristina Schubert , Martin Venker

We introduce the variable coherence model (VCM) for simulating free-electron laser (FEL) pulses generated through self-amplified spontaneous emission. Building on the established partial coherence model of [T. Pfeifer et. al, Opt. Lett. 35,…

Optics · Physics 2026-04-23 Austin Bartunek , Nils H. Sommerfeld , Francois Mauger

In this paper we study the computation of the nonparametric maximum likelihood estimator (NPMLE) in multivariate mixture models. Our first approach discretizes this infinite dimensional convex optimization problem by fixing the support…

Methodology · Statistics 2024-02-20 Yangjing Zhang , Ying Cui , Bodhisattva Sen , Kim-Chuan Toh

We review our recent work leading to steady-state solutions of the semiclassical (Maxwell-Bloch) equations of a laser. These are coupled non-linear partial differential equations in space and time which have previously been solved either by…

Many imaging applications require increasingly bright illumination sources, motivating the replacement of conventional thermal light sources with light emitting diodes (LEDs), superluminescent diodes (SLDs) and lasers. Despite their…

Optics · Physics 2017-04-05 Brandon Redding , Michael A. Choma , Hui Cao

Relativistic electron beams produced by intense lasers over short distances have important applications in high energy density physics and medical technologies. Vacuum laser acceleration with plasma mirrors injectors has garnered…

Plasma Physics · Physics 2025-11-19 Jiaxin Liu , Zeyue Pang , Hehanlin Wang , Zi-Yu Chen

In this paper, electromagnetic emissions produced in a thin beam-plasma system are studied using two-dimensional particle-in-cell simulations. For the first time, the problem of emission generation in such a system is considered in the…

Plasma Physics · Physics 2016-05-25 V. V. Annenkov , I. V. Timofeev , E. P. Volchok

A semi-classical approach is used to calculate radiation emission in the collision of an electron with an intense focused laser pulse. The results are compared to predictions from the locally constant field and locally monochromatic…

Plasma Physics · Physics 2022-08-17 Christian F. Nielsen , Robert Holtzapple , Ben King

We present a numerical model and a set of conservative algorithms for Non-Maxwellian plasma kinetics with inelastic collisions. These algorithms self-consistently solve for the time evolution of an isotropic electron energy distribution…

Plasma Physics · Physics 2017-12-12 H. P. Le , J. -L. Cambier

This paper presents a new Bayesian spectral unmixing algorithm to analyse remote scenes sensed via sparse multispectral Lidar measurements. To a first approximation, in the presence of a target, each Lidar waveform consists of a main peak,…

We present a parameter estimation technique based on performing joint measurements of a weak interaction away from the weak-value-amplification approximation. Two detectors are used to collect full statistics of the correlations between two…

Quantum Physics · Physics 2016-03-11 Julián Martínez-Rincón , Wei-Tao Liu , Gerardo I. Viza , John C. Howell

We present a method for computing uncertainties in spectral models, i.e. level populations, line emissivities, and emission line ratios, based upon the propagation of uncertainties originating from atomic data. We provide analytic…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Manuel A. Bautista , Vanessa Fivet , Pascal Quinet , Jay Dunn , Theodore R. Gull. Timothy R. Kallman , Claudio Mendoza

A high peak current, flat longitudinal phase space electron beam is desirable for efficient x-ray free electron laser (FEL) radiation in next generation light sources. To attain such a beam requires the extensive design of the linear…

Accelerator Physics · Physics 2019-10-23 Ji Qiang

If, in addition to the standard model fields, a new pseudoscalar field exists and couples to hypercharge topological number density, it can exponentially amplify hyperelectric and hypermagnetic fields in the symmetric phase of the…

High Energy Physics - Phenomenology · Physics 2016-08-25 Ram Brustein , David H. Oaknin

We introduce a loss compensation method to increase the resolution of near-field imaging with a plasmonic superlens that relies on the convolution of a high spatial frequency passband function with the object. Implementation with incoherent…

Optics · Physics 2018-01-23 Wyatt Adams , Anindya Ghoshroy , Durdu Ö. Güney

We consider and analyze applying a spectral inverse iteration algorithm and its subspace iteration variant for computing eigenpairs of an elliptic operator with random coefficients. With these iterative algorithms the solution is sought…

Numerical Analysis · Computer Science 2017-06-16 Harri Hakula , Mikael Laaksonen

We discuss the numerically stable, spectral-domain computation and extraction of the scattered electromagnetic field excited by distributed sources embedded in planar-layered environments, where each layer may exhibit arbitrary and…

Computational Physics · Physics 2016-02-17 Kamalesh Sainath , Fernando L. Teixeira