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A model for quantum tunnelling of a cluster comprising A identical particles, coupled by oscillator-type potential, through short-range repulsive potential barriers is introduced for the first time in the new symmetrized-coordinate…

We develop a time-dependent Hartree-Fock approximation that is appropriate for Bose-condensed systems. Defining a {\it depletion Green's function} allows the construction of condensate and depletion particle densities from eigenstates of a…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 C. -H. Zhang , H. A. Fertig

We show how to construct an effective Hamiltonian whose dimension scales linearly with system size, and whose eigenvalues systematically approximate the excitation energies of GW theory. This is achieved by rigorously expanding the…

Chemical Physics · Physics 2023-07-18 Charles J. C. Scott , Oliver J. Backhouse , George H. Booth

We present an approach to renormalized second-order Green's function perturbation theory (GF2) which avoids all dependency on continuous variables, grids or explicit Green's functions, and is instead formulated entirely in terms of static…

Chemical Physics · Physics 2020-06-26 Oliver J. Backhouse , Max Nusspickel , George H. Booth

We discuss applications of previously computed nuclear structure functions (SF) to inclusive cross sections, compare predictions with recent CEBAF data and perform two scaling tests. We mention that the large $Q^2$ plateau of scaling…

Nuclear Theory · Physics 2007-05-23 A. S. Rinat

Frequency control reserves are an essential ancillary service in any electric power system, guaranteeing that generation and demand of active power are balanced at all times. Traditionally, conventional power plants are used for frequency…

Systems and Control · Computer Science 2013-12-24 Theodor Borsche , Andreas Ulbig , Göran Andersson

The influence of large-scale density fluctuations on structure formation on small scales is described by the three-point correlation function (bispectrum) in the so-called "squeezed configurations," in which one wavenumber, say $k_3$, is…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-19 Chi-Ting Chiang , Christian Wagner , Fabian Schmidt , Eiichiro Komatsu

An attempt is made in QCD to explain the growth of total cross-sections with energy, without violating the Froissart bound. This is achieved by computing the phase shifts of elastic scatterings of partons rather than their amplitudes. To…

High Energy Physics - Phenomenology · Physics 2007-05-23 C. S. Lam

We derive expressions for the zeroth and the first three spectral moment sum rules for the retarded Green's function and for the zeroth and the first spectral moment sum rules for the retarded self-energy of the inhomogeneous Bose-Hubbard…

Quantum Gases · Physics 2015-01-12 J. K. Freericks , V. Turkowski , H. R. Krishnamurthy , M. Knap

A Green's function approach to the inclusive quasielastic ($e,e'$) scattering is presented. The components of the nuclear response are written in terms of the single-particle optical model Green's function. The explicit calculation of the…

Nuclear Theory · Physics 2007-05-23 F. Capuzzi , C. Giusti , A. Meucci , F. D. Pacati

We investigate the performance of Green's function coupled cluster singles and doubles (CCSD) method as a solver for Green's function embedding methods. To develop an efficient CC solver, we construct the one-particle Green's function from…

Strongly Correlated Electrons · Physics 2019-06-11 Avijit Shee , Dominika Zgid

The Green's function method in the \emph{Quasiparticle Time Blocking Approximation} is applied to nuclear excitations in $^{132}$Sn and $^{208}$Pb. The calculations are performed self-consistently using a Skyrme interaction. The method…

Nuclear Theory · Physics 2008-11-26 N. Lyutorovich , J. Speth , A. Avdeenkov , F. Gruemmer , S. Kamerdzhiev , S. Krewald , V. I. Tselyaev

We present a stochastic method for solving the time-dependent Schr\"odinger equation, generalizing a ground-state full configuration interaction Quantum Monte Carlo method. By performing the time-integration in the complex plane close to…

Strongly Correlated Electrons · Physics 2018-08-08 Kai Guther , Werner Dobrautz , Olle Gunnarsson , Ali Alavi

We introduce a new augmented adaptation of the recently developed full coupled-cluster reduction (FCCR) with a second-order perturbative correction, abbreviated as FCCR(2). FCCR is a selected coupled-cluster expansion aimed at optimally…

Chemical Physics · Physics 2020-11-06 Enhua Xu , Motoyuki Uejima , Seiichiro L. Ten-no

In this brief paper, we go through the theoretical steps of the spectral clustering on quantum computers by employing the phase estimation and the amplitude amplification algorithms. We discuss circuit designs for each step and show how to…

Quantum Physics · Physics 2017-07-24 Ammar Daskin

We consider the partition functions of QCD and QED at high temperature assuming small coupling constants, and present arguments in favor of an improved perturbative expansion in terms of unstable excitations. Our effective propagators are…

High Energy Physics - Phenomenology · Physics 2007-05-23 P. A. Henning , R. Sollacher

A size-extensive, converging, black-box, ab initio coupled-cluster ($\Delta$CC) ansatz is introduced that computes the energies and wave functions of stationary states from any degenerate or nondegenerate Slater-determinant references with…

Chemical Physics · Physics 2026-05-15 So Hirata

We explore the computation of high-harmonic generation spectra by means of Gaussian basis sets in approaches propagating the time-dependent Schr{\"o}dinger equation. We investigate the efficiency of Gaussian functions specifically designed…

Unitary coupled cluster (UCC), originally developed as a variational alternative to the popular traditional coupled cluster method, has seen a resurgence as a functional form for use on quantum computers. However, the number of excitors…

Chemical Physics · Physics 2021-01-07 Maria-Andreea Filip , Alex J. W. Thom

Spectral clustering is widely used in practice due to its flexibility, computational efficiency, and well-understood theoretical performance guarantees. Recently, spectral clustering has been studied to find balanced clusters under…

Machine Learning · Statistics 2022-03-07 Shubham Gupta , Ambedkar Dukkipati