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The eigenvalue of a Hamiltonian, $\mathcal{H}$, can be estimated through the phase estimation algorithm given the matrix exponential of the Hamiltonian, $exp(-i\mathcal{H})$. The difficulty of this exponentiation impedes the applications of…

Quantum Physics · Physics 2018-11-01 Ammar Daskin , Sabre Kais

Path integral implementation of the quantum instanton approximation currently belongs among the most accurate methods for computing quantum rate constants and kinetic isotope effects, but its use has been limited due to the rather high…

Chemical Physics · Physics 2017-05-10 Konstantin Karandashev , Jiri Vanicek

A new scheme to study the properties of finite nuclei is proposed based on the Dirac-Brueckner-Hartree-Fock (DBHF) approach starting from a bare nucleon-nucleon interaction. The relativistic structure of the nucleon self-energies in nuclear…

In this article, a fast algorithm based on time two-mesh (TT-M) finite element (FE) scheme, which aims at solving nonlinear problems quickly, is considered to numerically solve the nonlinear space fractional Allen-Cahn equations with smooth…

Numerical Analysis · Mathematics 2019-01-30 Baoli Yin , Yang Liu , Hong Li , Siriguleng He

We examine the problem of particle acceleration at a relativistic shocks assuming pitch-angle scattering and using a Hartree-Fock method to approximate the associated eigenfunctions. This leads to a simple transcendental equation…

Astrophysics · Physics 2009-11-13 Paul Dempsey , John G. Kirk

In this manuscript we propose and analyze an implicit two-point type method (or inertial method) for obtaining stable approximate solutions to linear ill-posed operator equations. The method is based on the iterated Tikhonov (iT) scheme. We…

Numerical Analysis · Mathematics 2024-01-30 Joel C. Rabelo , Antonio Leitão , Alexandre L. Madureira

The multiconfiguration Dirac-Hartree-Fock (MCDHF) method has been employed to calculate atomic electric dipole moments (EDM) of 225^Ra, 199^Hg, and 171^Yb. For the calculations of the matrix elements we extended the relativistic atomic…

Atomic Physics · Physics 2013-12-24 Laima Radziute , Gediminas Gaigalas , Per Jonsson , Jacek Biero

Time-dependent density functional theory (TDDFT) is a widely used method to investigate electron dynamics under various external perturbations such as laser fields. In this work, we present a novel approach to accelerate real time TDDFT…

Materials Science · Physics 2024-07-29 Karan Shah , Attila Cangi

Inertial navigation computation is to acquire the attitude, velocity and position information of a moving body by integrating inertial measurements from gyroscopes and accelerometers. Over half a century has witnessed great efforts in…

Robotics · Computer Science 2021-09-21 Yuanxin Wu

Repeated computations on the same molecular system, but with different geometries, are often performed in quantum chemistry, for instance, in ab-initio molecular dynamics simulations or geometry optimizations. While many efficient…

Chemical Physics · Physics 2020-12-02 E. Polack , A. Mikhalev , Geneviève Dusson , B. Stamm , F. Lipparini

We propose a high precision algorithm for solving the Gelfand-Levitan-Marchenko equation. The algorithm is based on the block version of the Toeplitz Inner-Bordering algorithm of Levinson's type. To approximate integrals, we use the…

Numerical Analysis · Mathematics 2024-05-02 Sergey Medvedev , Irina Vaseva , Mikhail Fedoruk

Computing excited states of many-body quantum Hamiltonians is a fundamental challenge in computational physics and chemistry, with state-of-the-art methods broadly classified into variational (critical point search) and linear response…

Chemical Physics · Physics 2026-02-27 Laura Grazioli , Yukuan Hu , Eric Cancès

We consider here variational solutions in the Hartree-Fock approximation upon breaking time reversal and axial symmetries. When decomposed on axial harmonic oscillator functions, the corresponding single particle triaxial eigenstates as…

Nuclear Theory · Physics 2009-10-31 D. Samsoen , P. Quentin , J. Bartel

We consider the problem of estimating parameters in large-scale weakly nonlinear inverse problems for which the underlying governing equations is a linear, time-dependent, parabolic partial differential equation. A major challenge in…

Numerical Analysis · Mathematics 2016-05-04 Tania Bakhos , Arvind K. Saibaba , Peter K. Kitanidis

Ultra-fast electronic phenomena originating from finite temperature, such as nonlinear optical excitation, can be simulated with high fidelity via real-time time dependent density functional theory (rt-TDDFT) calculations with hybrid…

Materials Science · Physics 2025-01-07 Rongrong Liu , Zhuoqiang Guo , Qiuchen Sha , Tong Zhao , Haibo Li , Wei Hu , Lijun Liu , Guangming Tan , Weile Jia

The structure of approximate two electron wavefunction is deeply investigated, both theoretically and numerically, in the strong-field driven ionization dynamics. Theoretical analyses clarify that for two electron singlet systems, the…

Atomic Physics · Physics 2014-11-13 Takeshi Sato , Kenichi L Ishikawa

We compute the leading-order inertial corrections to the instantaneous force acting on a rigid body moving with a time-dependent slip velocity in a linear flow field, assuming that the variation of the undisturbed flow at the body scale is…

Fluid Dynamics · Physics 2025-10-01 Fabien Candelier , Bernhard Mehlig , Jacques Magnaudet

We describe the inclusion of electrodynamic fields in Time-Dependent Density Functional Theory (TDDFT) by incorporating both the induced scalar and vector potentials within the time-dependent Kohn-Sham equation. The Hamiltonian is described…

Chemical Physics · Physics 2020-07-01 Dor Gabay , Ali Yilmaz , Vitaliy Lomakin , Amir Boag , Amir Natan

We apply the approximate dynamics derived from the Gaussian time-dependent variational principle to the Hamiltonian $ \hat H= {1/2}(\hat p_x ^2+ \hat p_y ^2)+ {1/2}\hat x^2\hat y^2$, which is strongly chaotic in the classical limit. We are…

chao-dyn · Physics 2016-08-31 Arjendu Pattanayak , William Schieve

Neural network force field (NNFF) is a method for performing regression on atomic structure-force relationships, bypassing expensive quantum mechanics calculation which prevents the execution of long ab-initio quality molecular dynamics…

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