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The dynamics of the nuclear-spin quantum computer with large number (L=1000) of qubits is considered using a perturbation approach, based on approximate diagonalization of exponentially large sparse matrices. Small parameters are introduced…

Quantum Physics · Physics 2007-05-23 G. P. Berman , D. I. Kamenev , V. I. Tsifrinovich

Quantum Monte Carlo (QMC) is a family of powerful tools for addressing quantum many-body problems. However, its applications are often plagued by the fermionic sign problem. A promising strategy is to simulate an interaction without sign…

Nuclear Theory · Physics 2025-05-01 Jun Liu , Teng Wang , Bing-Nan Lu

We devise an efficient algorithm for the symbolic calculation of irreducible angular momentum and spin (LS) eigenspaces within the $n$-fold antisymmetrized tensor product $\wedge^n V_u$, where $n$ is the number of electrons and $u =…

Atomic Physics · Physics 2016-01-19 Christian B. Mendl

The new class of alternating-conjugate splitting methods is presented and analyzed. They are obtained by concatenating a given composition involving complex coefficients with the same composition but with the complex conjugate coefficients.…

Numerical Analysis · Mathematics 2025-12-19 J. Bernier , S. Blanes , F. Casas , A. Escorihuela-Tomàs

Ionization rates and Stark shifts of H$_2$, CO, O$_2$, H$_2$O, and CH$_4$ in static electric fields have been computed with coupled-cluster methods in a basis set of atom-centered Gaussian functions with complex-scaled exponent.…

Chemical Physics · Physics 2018-06-13 Thomas-C. Jagau

A multiscale approach was adopted for the calculation of confined states in self-assembled semiconductor quantum dots (QDs). While results close to experimental data have been obtained with a combination of atomistic strain and…

Mesoscale and Nanoscale Physics · Physics 2014-09-16 Parijat Sengupta , Sunhee Lee , Sebastian Steiger , Hoon Ryu , Gerhard Klimeck

A method for integrating the chemical equations associated with nuclear combustion at high temperature is presented and extensively checked. Following the idea of E. M\"uller, the feedback between nuclear rates and temperature was taken…

Astrophysics · Physics 2007-05-23 Ruben M. Cabezon Gomez , Domingo Garcia-Senz , Eduardo Bravo

Simultaneous analyses are performed for cross section data of elastic scattering, fusion, Coulomb breakup, and other direct yields for the $^{6}$He+$^{209}$Bi system at near-Coulomb-barrier energies. The bare and dynamical polarization…

Nuclear Theory · Physics 2024-02-08 H. M. Maridi , N. Keeley , K. Rusek

The determination of the effective Coulomb interactions to be used in low-energy Hamiltonians for materials with strong electronic correlations remains one of the bottlenecks for parameter-free electronic structure calculations. We propose…

Strongly Correlated Electrons · Physics 2017-08-09 Priyanka Seth , Philipp Hansmann , Ambroise van Roekeghem , Loig Vaugier , Silke Biermann

The article presents and documents the Mathematica package SymBuild. This package implements the computation and manipulation of integrable symbols appearing in various calculations in high-energy scattering amplitudes. By using Gr\"obner…

High Energy Physics - Theory · Physics 2018-11-01 Vladimir Mitev , Yang Zhang

Calculating interactions or correlations between pairs of particles is typically the most time-consuming task in particle simulation or correlation analysis. Straightforward implementations using a double loop over particle pairs have…

Computational Physics · Physics 2015-06-16 Szilárd Páll , Berk Hess

Coulomb dissociation is an especially simple and important reaction mechanism. Since the perturbation due to the electric field of the nucleus is exactly known, firm conclusions can be drawn from such measurements. Electromagnetic matrix…

Nuclear Theory · Physics 2009-11-06 Gerhard Baur , Kai Hencken , Dirk Trautmann , Stefan Typel , Hermann H. Wolter

We demonstrate an efficient numerical method to calculate three-tangle of general mixed states. We construct a "energy function" (target function) for the three-tangle of the mixed state under certain constrains. The "energy function"…

Quantum Physics · Physics 2015-05-14 Kun Cao , Zheng-Wei Zhou , Guang-Can Guo , Lixin He

We have developed a set of techniques for performing large scale ab initio calculations using multigrid accelerations and a real-space grid as a basis. The multigrid methods permit efficient calculations on ill-conditioned systems with long…

mtrl-th · Physics 2009-10-28 E. L. Briggs , D. J. Sullivan , J. Bernholc

We compute the reduced electric-dipole matrix elements $\langle{nS_{1/2}}||D||{n'P_J}\rangle$ with $n=6,7$ and $n'=6,7,\ldots,12$ in cesium using the most complete to date ab initio relativistic coupled-cluster method which includes…

Atomic Physics · Physics 2023-05-03 H. B. Tran Tan , A. Derevianko

The Atomic Cluster Expansion (Drautz, Phys. Rev. B 99, 2019) provides a framework to systematically derive polynomial basis functions for approximating isometry and permutation invariant functions, particularly with an eye to modelling…

Numerical Analysis · Mathematics 2021-05-13 Genevieve Dusson , Markus Bachmayr , Gabor Csanyi , Ralf Drautz , Simon Etter , Cas van der Oord , Christoph Ortner

Emergent properties such as nuclear saturation and deformation, and the effects on shell structure due to the proximity of the scattering continuum and particle decay channels are fascinating phenomena in atomic nuclei. In recent years, ab…

Nuclear Theory · Physics 2016-05-19 G. Hagen , M. Hjorth-Jensen , G. R. Jansen , T. Papenbrock

We present a comprehensive analysis of the coupled scheme introduced in [Springer Proceedings in Mathematics \& Statistics, vol 237. Springer, Cham 2018 \cite{S2018}] for linear and Hamilton-Jacobi equations. This method merges two distinct…

Numerical Analysis · Mathematics 2023-10-13 Smita Sahu

Recent progress in the numerical solution of the nuclear many-body problem and in the development of nuclear Hamiltonians rooted in Quantum Chromodynamics, has opened the door to first-principle computations of nuclear reactions. In this…

Nuclear Theory · Physics 2020-07-24 J. Rotureau

The aim of this work is to study the physical properties of a one-way quantum computer in an effective low-energy cluster state. We calculate the optimal working conditions as a function of the temperature and of the system parameters. The…

Quantum Physics · Physics 2011-11-28 D. Klagges , K. P. Schmidt