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Time-driven quantum systems are important in many different fields of physics like cold atoms, solid state, optics, etc. Many of their properties are encoded in the time evolution operator which is calculated by using a time-ordered product…

We have developed a time propagation scheme for the Kadanoff-Baym equations for general inhomogeneous systems. These equations describe the time evolution of the nonequilibrium Green function for interacting many-body systems in the…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Adrian Stan , Nils Erik Dahlen , Robert van Leeuwen

We present a new theory for partitioning simulations of periodic and solid-state systems into physically sound atomic contributions at the level of Kohn-Sham density functional theory. Our theory is based on spatially localized linear…

Chemical Physics · Physics 2024-10-01 Luna Zamok , Janus J. Eriksen

An approximate method based on adiabatic time dependent density functional theory (TDDFT) is presented, that allows for the description of the electron dynamics in nanoscale junctions under arbitrary time dependent external potentials. In…

Mesoscale and Nanoscale Physics · Physics 2015-05-27 Y. Wang , C. -Y. Yam , G. H. Chen , Th. Frauenheim , T. A. Niehaus

We propose an approach to determine the continual progression of algorithmic efficiency, as an alternative to standard calculations of time complexity, likely, but not exclusively, when dealing with data structures with unknown maximum…

Computational Complexity · Computer Science 2020-12-04 Ananth Goyal

We study the problem of estimating the covariance matrix of a high-dimensional distribution when a small constant fraction of the samples can be arbitrarily corrupted. Recent work gave the first polynomial time algorithms for this problem…

Machine Learning · Computer Science 2019-06-12 Yu Cheng , Ilias Diakonikolas , Rong Ge , David Woodruff

Sensing and imaging with distributed radio infrastructures (e.g., distributed MIMO, wireless sensor networks, multistatic radar) rely on knowledge of the positions, orientations, and clock parameters of distributed apertures. We extend a…

Signal Processing · Electrical Eng. & Systems 2025-05-29 Benjamin J. B. Deutschmann , Peter Vouras

The probability distribution (PD) of spin configurations in kinetic Ising models has been cast in the form of the canonical Boltzmann PD with a time-dependent effective Hamiltonian (EH). It has been argued that in systems with extensive…

Statistical Mechanics · Physics 2025-06-10 V. I. Tokar

In this paper, we propose and analyze a gradient flow based Kohn-Sham density functional theory. First, we prove that the critical point of the gradient flow based model can be a local minimizer of the Kohn-Sham total energy. Then we apply…

Numerical Analysis · Mathematics 2019-07-16 Xiaoying Dai , Qiao Wang , Aihui Zhou

Studying the propagation of uncertainties in a nonlinear dynamical system usually involves generating a set of samples in the stochastic parameter space and then repeated simulations with different sampled parameters. The main difficulty…

Numerical Analysis · Mathematics 2017-09-19 Nan Jiang , Michael Schneier

We present a multiscale integrator for Hamiltonian systems with slowly varying quadratic stiff potentials that uses coarse timesteps (analogous to what the impulse method uses for constant quadratic stiff potentials). This method is based…

Numerical Analysis · Mathematics 2011-04-14 Molei Tao , Houman Owhadi , Jerrold E. Marsden

Even in large systems, the effect of noise arising from when populations are initially small can persist to be measurable on the macroscale. A deterministic approximation to a stochastic model will fail to capture this effect, but it can be…

Populations and Evolution · Quantitative Biology 2024-08-13 Dylan Morris , John Maclean , Andrew J. Black

We propose efficient and parallel algorithms for the implementation of the high-order continuous time Galerkin method for dissipative and wave propagation problems. By using Legendre polynomials as shape functions, we obtain a special…

Numerical Analysis · Mathematics 2023-03-10 Zhiming Chen , Yong Liu

We consider wave propagation through a 1D periodic network of slowly time-modulated interfaces. Each interface is modelled by time-dependent spring-mass jump conditions, where mass and rigidity interface parameters are modulated in time.…

Mathematical Physics · Physics 2026-03-31 Michaël Darche , Raphaël Assier , Sébastien Guenneau , Bruno Lombard , Marie Touboul

We derive the general Kubo formula in a form that solely utilizes the time evolution of displacement operators. The derivation is based on the decomposition of the linear response function into its time symmetric and time anti-symmetric…

Mesoscale and Nanoscale Physics · Physics 2021-07-07 Michel Panhans , Frank Ortmann

The density functional approach in the Kohn-Sham approximation is widely used to study properties of many-electron systems. Due to the nonlinearity of the Kohn-Sham equations, the general self-consistence searching method involves…

Materials Science · Physics 2015-05-13 D. V. Posvyanskii , A. Ya. Shul'man

An analytical method for investigation of the evolution of dynamical systems {\it with independent on time accuracy} is developed for perturbed Hamiltonian systems. The error-free estimation using of computer algebra enables the application…

Instrumentation and Methods for Astrophysics · Physics 2016-12-13 A. V. Gurzadyan , A. A. Kocharyan

We study the work distribution of a single particle moving in a harmonic oscillator with time-dependent strength. This simple system has a non-Gaussian work distribution with exponential tails. The time evolution of the corresponding moment…

Statistical Mechanics · Physics 2011-07-01 Thomas Speck

Two of the most widely used electronic structure theory methods, namely Hartree-Fock and Kohn-Sham density functional theory, both requires the iterative solution of a set of Schr\"odinger-like equations. The speed of convergence of such…

Chemical Physics · Physics 2024-06-06 S. Hazra , U. Patil , S. Sanvito

We discuss the propagation dynamics of nonspreading wave packets. We decompose the Hamiltonian into two parts. The first part is such that wave packets is its instantaneous eigenstate and is therefore irrelevant to the propagation of the…

Quantum Physics · Physics 2013-06-07 Chyi-Lung Lin
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