English
Related papers

Related papers: RCCPAC: A parallel relativistic coupled-cluster pr…

200 papers

We report the implementation of 4-component spinor relativistic equation-of-motion coupledcluster method within the single- and double- excitation approximation to calculate ionization potential (EOM-CCSD) of molecules. We have applied this…

Chemical Physics · Physics 2015-02-25 Himadri Pathak , Sudip Sasmal , Malaya K. Nayak , Nayana Vaval , Sourav Pal

Classical atomistic simulations based on interatomic potentials resolve lattice instabilities, defect nucleation, and microstructure evolution with high fidelity, but their accessible system sizes remain far below those required for…

Numerical Analysis · Mathematics 2026-05-26 Aagashram Neelakandan , Karsten Albe , Bernhard Eidel

The nonperturbative Hamiltonian eigenvalue problem for bound states of a quantum field theory is formulated in terms of Dirac's light-front coordinates and then approximated by the exponential-operator technique of the many-body…

High Energy Physics - Phenomenology · Physics 2015-06-11 J. R. Hiller

We demonstrate behaviors of correlation effects in the calculations of atomic properties through two commonly employed many-body methods; namely multiconfiguration Dirac-Hartree-Fock (MCDHF) and relativistic coupled-cluster (RCC) methods.…

Atomic Physics · Physics 2025-04-29 B. K. Sahoo , Per Jönsson , Gediminas Gaigalas

We introduce a multimodel approach to solve coupled cluster equations, employing a quasi Newton algorithm for the ground state and an Olsen algorithm for the excited states. In these algorithms, both of which can be viewed as Newton…

Chemical Physics · Physics 2020-07-15 Eirik F. Kjønstad , Sarai D. Folkestad , Henrik Koch

The numerical solution of the Vlasov-Fokker-Planck equation is a well established method to simulate the dynamics, including the self-interaction with its own wake field, of an electron bunch in a storage ring. In this paper we present…

Fracton topological phases have a large number of materialized symmetries that enforce a rigid structure on their excitations. Remarkably, we find that the symmetries of a quantum error-correcting code based on a fracton phase enable us to…

Quantum Physics · Physics 2020-04-02 Benjamin J. Brown , Dominic J. Williamson

We present an embedding approach to treat local electron correlation effects in periodic environments. In a single, consistent framework, our plane-wave based scheme embeds a local high-level correlation calculation (here Coupled Cluster…

Chemical Physics · Physics 2021-01-07 Tobias Schäfer , Florian Libisch , Georg Kresse , Andreas Grüneis

This study addresses the challenge of simulating realistic particle systems by proposing a novel particle decomposition scheme that improves the parallel performance of surface resolved particle simulations. Realistic particle systems often…

Fluid Dynamics · Physics 2024-03-21 J. E. Marquardt , N. Hafen , M. J. Krause

In this article we study the effects of higher body excitations in the relativistic CC calculations for atoms and ions with one valence electron using Fock-space CCSD, CCSD(T) and its unitary variants. The present study demonstrates that…

Atomic Physics · Physics 2009-11-13 Chiranjib Sur , Rajat K Chaudhuri

Relativistic atomic structure calculations are carried out in alkaline-earth-metal ions using a semiempirical-core-potential approach. The systems are partitioned into frozen-core electrons and an active valence electron. The core orbitals…

We report an implementation of the core-valence separation approach to the 4-component relativistic Hamiltonian based equation-of-motion coupled-cluster with singles and doubles theory (CVS-EOM-CCSD), for the calculation of relativistic…

We investigate collective multipole excitations for closed shell nuclei from 16O to 208Pb using correlated realistic nucleon -nucleon interactions in the framework of the random phase approximation (RPA). The dominant short-range central…

Nuclear Theory · Physics 2009-11-11 N. Paar , P. Papakonstantinou , H. Hergert , R. Roth

We present a review of the Unitary Coupled Cluster (UCC) ansatz and related ans\"atze which are used to variationally solve the electronic structure problem on quantum computers. A brief history of coupled cluster (CC) methods is provided,…

Understanding nuclear forces, infinite nuclear matter, and finite nuclei within a unified framework has remained a central challenge in nuclear physics for decades. While most \textit{ab initio} studies employ nonrelativistic…

Nuclear Theory · Physics 2025-07-03 Shihang Shen , Jun-Xu Lu , Li-Sheng Geng , Jie Meng , Wei-Jiang Zou

An approach has been devised and tested for preserving the molecular geometry and taking into account energetic considerations during Reverse Monte Carlo modeling. Instead of the commonly used fixed neighbour constraints, where molecules…

Disordered Systems and Neural Networks · Physics 2012-06-15 Orsolya Gereben , Laszlo Pusztai

We show that a simple correlated wave function, obtained by applying a Jastrow correlation term to an Antisymmetrized Geminal Power (AGP), based upon singlet pairs between electrons, is particularly suited for describing the electronic…

Other Condensed Matter · Physics 2009-11-10 M. Casula , C. Attaccalite , S. Sorella

We present a computer code that analytically evaluates the matrix elements of the microscopic nuclear Hamiltonian and unity operator between Slater determinants of displaced gaussian single particle orbits. Such matrix elements appear in…

Nuclear Theory · Physics 2009-10-22 K. Varga

We report on quantum simulations of relativistic scattering dynamics using trapped ions. The simulated state of a scattering particle is encoded in both the electronic and vibrational state of an ion, representing the discrete and…

We propose the regularized compressed double factorization (RC-DF) method to classically compute compressed representations of molecular Hamiltonians that enable efficient simulation with noisy intermediate scale (NISQ) and error corrected…