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Related papers: QED-SCF, MCSCF and Coupled-cluster Methods in Quan…

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We show that maximally twisted mass fermions can be employed to regularize on the lattice the fully unquenched QCD+QED theory with vanishing $\theta$-term. We discuss how the critical mass of the up and down quarks can be conveniently…

High Energy Physics - Lattice · Physics 2016-12-08 Roberto Frezzotti , Giancarlo Rossi , Nazario Tantalo

We calculate the dynamics of one and two two-level atoms interacting with the electromagnetic vacuum field in the vicinity of an optical nanofiber without making either the Born or the Markov approximations. We use a constant dielectric…

Quantum Physics · Physics 2023-07-19 Alberto Del Ángel , P. Solano , P. Barberis-Blostein

We consider the leading post-Newtonian and quantum corrections to the non-relativistic scattering amplitude of charged spin-1/2 fermions in the combined theory of general relativity and QED. The coupled Dirac-Einstein system is treated as…

General Relativity and Quantum Cosmology · Physics 2008-11-26 M. S. Butt

Estimating the relative alignment between the frontier molecular orbitals that dominates the charge transport through single-molecule junctions represents a challenge for theory. This requires approaches beyond the widely employed framework…

Mesoscale and Nanoscale Physics · Physics 2015-09-22 Ioan Baldea

We propose an orbital optimized method for unitary coupled cluster theory (OO-UCC) within the variational quantum eigensolver (VQE) framework for quantum computers. OO-UCC variationally determines the coupled cluster amplitudes and also…

Strongly Correlated Electrons · Physics 2020-09-23 Wataru Mizukami , Kosuke Mitarai , Yuya O. Nakagawa , Takahiro Yamamoto , Tennin Yan , Yu-ya Ohnishi

The iterative qubit coupled cluster (iQCC) method is a systematic variational approach to solve the electronic structure problem on universal quantum computers. It is able to use arbitrarily shallow quantum circuits at expense of iterative…

Quantum Physics · Physics 2020-09-30 Ilya G. Ryabinkin , Artur F. Izmaylov , Scott N. Genin

A previously proposed non-canonical coupled-perturbed Kohn-Sham density functional theory (KS-DFT)/Hartree-Fock (HF) treatment for spin-orbit coupling is here generalized to infinite periodic systems. The scalar-relativistic periodic…

Accurate electronic structure calculations are essential in modern materials science, but strongly correlated systems pose a significant challenge due to their computational cost. Traditional methods, such as complete active space…

Chemical Physics · Physics 2024-12-11 Pavlo Golub , Chao Yang , Vojtěch Vlček , Libor Veis

Projection-based embedding offers a simple framework for embedding correlated wavefunction methods in density functional theory. Partitioning between the correlated wavefunction and density functional subsystems is performed in the space of…

Chemical Physics · Physics 2018-10-16 Matthew Welborn , Frederick R. Manby , Thomas F. Miller

In the framework of semiclassical theory the universal properties of quantum systems with classically chaotic dynamics can be accounted for through correlations between partner periodic orbits with small action differences. So far, however,…

Chaotic Dynamics · Physics 2016-02-17 Boris Gutkin , Vladimir Osipov

For studying the group theoretical classification of the solutions of the density functional theory in relativistic framework, we propose quantum electrodynamical density-matrix functional theory (QED-DMFT). QED-DMFT gives the energy as a…

Chemical Physics · Physics 2007-05-23 Tadafumi Ohsaku , Shusuke Yamanaka , Daisuke Yamaki , Kizashi Yamaguchi

We present a quantum-classical hybrid algorithm that simulates electronic structures of periodic systems such as ground states and quasiparticle band structures. By extending the unitary coupled cluster (UCC) theory to describe crystals in…

Quantum Physics · Physics 2022-02-16 Nobuyuki Yoshioka , Takeshi Sato , Yuya O. Nakagawa , Yu-ya Ohnishi , Wataru Mizukami

In a series of two articles, we propose a comprehensive mathematical framework for Coupled-Cluster-type methods. These methods aim at accurately solving the many-body Schrodinger equation. In this first part, we rigorously describe the…

Numerical Analysis · Mathematics 2023-03-28 Mihály A. Csirik , Andre Laestadius

An efficient perturbational treatment of spin-orbit coupling within the framework of high-level multi-reference techniques has been implemented in the most recent version of the COLUMBUS quantum chemistry package, extending the existing…

Understanding physical properties of quantum emitters strongly interacting with quantized electromagnetic modes is one of the primary goals in the emergent field of waveguide quantum electrodynamics (QED). When the light-matter coupling…

Quantum Physics · Physics 2023-05-30 Yuto Ashida , Takeru Yokota , Atac Imamoglu , Eugene Demler

Quantum mechanical effects at the macroscopic level were first explored in Josephson junction-based superconducting circuits in the 1980's. In the last twenty years, the emergence of quantum information science has intensified research…

Quantum Physics · Physics 2021-05-26 Alexandre Blais , Arne L. Grimsmo , S. M. Girvin , Andreas Wallraff

Sample-based quantum diagonalization (SQD) is a hybrid quantum-classical algorithm for estimating ground-state energies in electronic-structure calculations. It uses a quantum processor as a sampler to construct a variational subspace, with…

Quantum Physics · Physics 2026-04-21 Byeongyong Park , Sanha Kang , Jongseok Seo , Juhee Baek , Doyeol Ahn , Keunhong Jeong

We recently proposed a novel approach to converging electronic energies equivalent to high-level coupled-cluster (CC) computations by combining the deterministic CC($P$;$Q$) formalism with the stochastic configuration interaction (CI) and…

Chemical Physics · Physics 2021-03-23 J. Emiliano Deustua , Jun Shen , Piotr Piecuch

Ab initio quantum chemistry calculations for systems with large active spaces are notoriously difficult and cannot be successfully tackled by standard methods. In this letter, we generalize a Green's function QM/QM embedding method called…

Chemical Physics · Physics 2018-06-07 Tran Nguyen Lan , Dominika Zgid

Systems with the quantum numbers of up to twelve charged and neutral pseudoscalar mesons, as well as one-, two-, and three-nucleon systems, are studied using dynamical lattice quantum chromodynamics and quantum electrodynamics (QCD+QED)…