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We calculate the $^{16}$O spectral function by combining coupled-cluster theory with a Gaussian integral transform and by expanding the integral kernel in terms of Chebyshev polynomials to allow for a quantification of the theoretical…

Nuclear Theory · Physics 2023-09-04 Joanna E. Sobczyk , Sonia Bacca

We study the exact one electron propagator and spectral function of a solvable model of interacting electrons due to Schulz and Shastry. The solution previously found for the energies and wave functions is extended to give the spectral…

Strongly Correlated Electrons · Physics 2009-02-27 Karlo Penc , B. Sriram Shastry

We study the charge-density dynamics within the two-dimensional extended Hubbard model in the presence of long-range Coulomb interaction across the metal-insulator transition point. To take into account strong correlations we start from…

Strongly Correlated Electrons · Physics 2014-12-24 E. G. C. P. van Loon , H. Hafermann , A. I. Lichtenstein , A. N. Rubtsov , M. I. Katsnelson

Spectroscopies that probe electronic excitations from core levels into unoccupied orbitals, such as X-ray absorption spectroscopy and electron energy loss spectroscopy, are widely used to gain insight into the electronic and chemical…

Materials Science · Physics 2022-09-12 Marcus Annegarn , Juhan Matthias Kahk , Johannes Lischner

The fate of spin-charge separation beyond the low energy remains elusive up to now. Here we develop a microscopic theory of the correlation functions using the strong coupling expansion of the Hubbard model and demonstrate its validity down…

Strongly Correlated Electrons · Physics 2025-10-13 Oleksandr Tsyplyatyev , Yiqing Jin , María Moreno , Wooi Kiat Tan , Christopher J. B. Ford

We developed a novel approach based on a generalization of factorization and nuclear spectral functions, allowing for a consistent treatment of the amplitudes involving one- and two-nucleon currents, whose contribution to the nuclear…

Nuclear Theory · Physics 2016-05-18 Noemi Rocco , Alessandro Lovato , Omar Benhar

We use, for the first time, ab initio coupled-cluster theory to compute the spectral function of the uniform electron gas at a Wigner-Seitz radius of $r_\mathrm{s}=4$. The coupled-cluster approximations we employ go significantly beyond the…

Interacting electrons in a semiconductor quantum dot at strong magnetic fields exhibit a rich set of states, including correlated quantum fluids and crystallites of various symmetries. We develop in this paper a perturbative scheme based on…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Gun Sang Jeon , Chia-Chen Chang , Jainendra K. Jain

Analytical results on the correlation functions of strongly correlated many-body systems are rare in the literature and their importance cannot be overstated. We present determinant representations for the space-, time-, and…

Strongly Correlated Electrons · Physics 2024-11-12 Ovidiu I. Patu , Andreas Klumper , Angela Foerster

We compute exactly both the spectral function of the electron and of the small polaron for the two site Holstein model. We find that for intermediary coupling, the small polaron is a better fundamental excitation of the system than the…

Strongly Correlated Electrons · Physics 2009-10-30 J. M. Robin

A general theory of electronic excitations in aggregates of molecules coupled to intramolecular vibrations and the harmonic environment is developed for simulation of the third-order nonlinear spectroscopy signals. The model is applied in…

Chemical Physics · Physics 2014-01-17 Vytautas Butkus , Leonas Valkunas , Darius Abramavicius

The spectral function of protons in the asymmetric nuclear matter is calculated in the self-consistent T-matrix approach. The spectral function per proton increases with increasing asymmetry. This effect and the density dependence of the…

Nuclear Theory · Physics 2014-11-18 P. Bozek

The one electron spectral functions for the Luttinger model are discussed for large but finite systems. The methods presented allow a simple interpretation of the results. For finite range interactions interesting nonunivesal spectral…

Condensed Matter · Physics 2009-10-22 K. Schönhammer , V. Meden

By analysing the high momentum features of the nucleon momentum distribution in light and complex nuclei, it is argued that the basic two-nucleon configurations generating the structure of the nucleon Spectral Function at high values of the…

Nuclear Theory · Physics 2008-11-26 C. Ciofi degli Atti , S. Simula

This article is aimed at improving the description of lepton-nucleus interactions in the sub-GeV energy range. Approximate spectral functions for oxygen, calcium, and argon are constructed and used to obtain the electron cross sections in a…

Nuclear Theory · Physics 2008-11-26 Artur M. Ankowski , Jan T. Sobczyk

In the context of the density functional theory we consider the single particle excitation spectra of electron systems. As a result, we have related the single particle excitations with the eigenvalues of the corresponding Kohn-Sham…

Condensed Matter · Physics 2009-10-31 M. Ya. Amusia , V. R. Shaginyan

The coupling space of perceptrons with continuous as well as with binary weights gets partitioned into a disordered multifractal by a set of $p=\gamma N$ random input patterns. The multifractal spectrum $f(\alpha)$ can be calculated…

Disordered Systems and Neural Networks · Physics 2009-10-28 M. Weigt , A. Engel

This work addresses the incorporation of Coulomb interactions into femtoscopy correlation functions (CFs) used to probe hadron interactions. Combining strong contact potentials with Coulomb effects, the derived scattering amplitudes and…

High Energy Physics - Phenomenology · Physics 2025-09-26 M. Albaladejo , A. Garcia-Lorenzo , J. Nieves

Using the strong coupling diagram technique for calculating the electron Green's function of the two-dimensional Hubbard model we have summed infinite sequences of ladder diagrams, which describe interactions of electrons with spin and…

Strongly Correlated Electrons · Physics 2018-10-30 A. Sherman

We derive analytical expressions for the correlation functions of the electronic conductance fluctuations of an open quantum dot under several conditions. Both the variation of energy and that of an external parameter such as an applied…

Mesoscale and Nanoscale Physics · Physics 2017-03-22 J. G. G. S. Ramos , A. L. R. Barbosa , B. V. Carlson , T. Frederico , M. S. Hussein