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The spectral properties of a multilevel atomic system interacting with multiple electromagnetic fields, a modified inverted-Y system, have been theoretically investigated. In this study, a numerical matrix propagation method has been…

Atomic Physics · Physics 2019-05-22 Charu Mishra , A. Chakraborty , S. R. Mishra

Classification and characterization of variable phenomena and transient phenomena are critical for astrophysics and cosmology. These objects are commonly studied using photometric time series or spectroscopic data. Given that many ongoing…

Instrumentation and Methods for Astrophysics · Physics 2020-01-08 Javiera Astudillo , Pavlos Protopapas , Karim Pichara , Pablo Huijse

Context. Recently our ability to study stars using asteroseismic techniques has increased dramatically, largely through the use of space based photometric observations. Work has also been done using ground based spectroscopic observations…

Solar and Stellar Astrophysics · Physics 2018-10-03 Jesper Schou

We present a time-linear scaling method to simulate open and correlated quantum systems out of equilibrium. The method inherits from many-body perturbation theory the possibility to choose selectively the most relevant scattering processes…

Mesoscale and Nanoscale Physics · Physics 2025-06-10 R. Tuovinen , Y. Pavlyukh , E. Perfetto , G. Stefanucci

We present a polynomial-time quantum algorithm for obtaining the energy spectrum of a physical system, i.e. the differences between the eigenvalues of the system's Hamiltonian, provided that the spectrum of interest contains at most a…

Quantum Physics · Physics 2012-06-22 Hefeng Wang , S. Ashhab , Franco Nori

The frequency distribution of different parameters of an EXAFS spectrum can be directly sampled by analysing a population of simulated spectra produced by adding computer-generated noise to a reference pattern. The procedure gives…

Data Analysis, Statistics and Probability · Physics 2007-05-23 Paolo Ghigna , Melissa di Muri , Giorgio Spinolo

The statistical properties of coherent radiation scattered from phase-ordering materials are studied in detail using large-scale computer simulations and analytic arguments. Specifically, we consider a two-dimensional model with a…

Statistical Mechanics · Physics 2009-10-30 Gregory Brown , Per Arne Rikvold , Mark Sutton , Martin Grant

In order to choose a numerical method for solving the time dependent equations of radiative transport, we obtain an exact solution for the time dependent radiation field in a one dimensional infinite medium with monochromatic, isotropic…

Astrophysics · Physics 2009-11-13 D. I. Nagirner , S. L. Kirusheva

This paper describes a method of calculating the transforms, currently obtained via Fourier and reverse Fourier transforms. The method allows calculating efficiently the transforms of a signal having an arbitrary dimension of the digital…

Numerical Analysis · Mathematics 2025-10-20 Vladimir I Clue

A scattering transform defines a locally translation invariant representation which is stable to time-warping deformations. It extends MFCC representations by computing modulation spectrum coefficients of multiple orders, through cascades…

Sound · Computer Science 2015-06-15 Joakim Andén , Stéphane Mallat

Chaotic systems that decompose into two cells connected only by a narrow channel exhibit characteristic deviations of their quantum spectral statistics from the canonical random-matrix ensembles. The equilibration between the cells…

chao-dyn · Physics 2016-08-31 Thomas Dittrich , Gert Koboldt , Bernhard Mehlig , Holger Schanz

We report a numerical calculation of the two-photon absorption coefficient of electrons in a binding potential using the real-time real-space higher-order difference method. By introducing random vector averaging for the intermediate state,…

Materials Science · Physics 2009-10-31 Yoshiyuki Kurokawa , Shintaro Nomura , Tadashi Takemori , Yoshinobu Aoyagi

A time-dependent approach for the kinetic energy release (KER) spectrum is developed for a fragmentation of a diatomic molecule after an electronic decay process, e.g. Auger process. It allows one to simulate the time-resolved spectra and…

Atomic Physics · Physics 2012-03-20 Ying-Chih Chiang , Frank Otto , Hans-Dieter Meyer , Lorenz S. Cederbaum

We present an ab initio approach to solve the time-dependent Schr\"odinger equation to treat electron and photon impact multiple ionization of atoms or molecules. It combines the already known time scaled coordinate method with a new high…

Light beams can be characterized by their complex spatial profiles in both intensity and phase. Analogous to time signals, which can be decomposed into multiple orthogonal frequency functions, a light beam can also be decomposed into a set…

We provide a method for estimating spectral gaps in low-dimensional systems. Unlike traditional phase estimation, our approach does not require ancillary qubits nor does it require well characterised gates. Instead, it only requires the…

Quantum Physics · Physics 2016-06-22 Ilia Zintchenko , Nathan Wiebe

Consider the wave equation with heterogeneous coefficients in the homogenization regime. At large times, the wave interacts in a nontrivial way with the heterogeneities, giving rise to effective dispersive effects. The main achievement of…

Analysis of PDEs · Mathematics 2024-02-22 Mitia Duerinckx , Antoine Gloria , Matthias Ruf

We derive the distribution of eigenvalues of the reduced density matrix of a block of length l in a one-dimensional system in the scaling regime. The resulting "entanglement spectrum" is described by a universal scaling function depending…

Strongly Correlated Electrons · Physics 2009-11-13 Pasquale Calabrese , Alexandre Lefevre

The results obtained by analyzing signals with the Square Wave Method (SWM) introduced previously can be presented in the frequency domain clearly and precisely by using the Square Wave Transform (SWT) described here. As an example, the SWT…

Numerical Analysis · Computer Science 2015-11-13 Osvaldo Skliar , Ricardo E. Monge , Guillermo Oviedo , Sherry Gapper

The excited state dynamics of chromophores in complex environments determine a range of vital biological and energy capture processes. Time-resolved, multidimensional optical spectroscopies provide a key tool to investigate these processes.…