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We present and review an efficient method to calculate the retarded Green's function in multi-terminal nanostructures; which is needed in order to calculate the conductance through the system and the local particle densities within it. The…

Mesoscale and Nanoscale Physics · Physics 2015-06-16 G. Thorgilsson , G. Viktorsson , S. I. Erlingsson

We present a new method for extracting numerically exact imaginary-time Green functions from standard Hirsch-Fye quantum Monte Carlo (HF-QMC) simulations within dynamical mean-field theory. By analytic continuation, angular resolved spectra…

Strongly Correlated Electrons · Physics 2007-12-11 N. Blümer

Flexible boundary condition methods couple an isolated defect to bulk through the bulk lattice Green's function. The inversion of the force-constant matrix for the lattice Green's function requires Fourier techniques to project out the…

Materials Science · Physics 2010-05-28 M. Ghazisaeidi , D. R. Trinkle

Non-equilibrium Green's function theory and related methods are widely used to describe transport phenomena in many-body systems, but they often require a costly inversion of a large matrix. We show here that the shift-invert Lanczos method…

Nuclear Theory · Physics 2025-01-14 K. Uzawa , K. Hagino

Quantum computing opens up new possibilities for the simulation of many-body nuclear systems. As the number of particles in a many-body system increases, the size of the space if the associated Hamiltonian increases exponentially. This…

Quantum Physics · Physics 2022-09-19 Isaac Hobday , Paul Stevenson , James Benstead

Determining the properties of molecules and materials is one of the premier applications of quantum computing. A major question in the field is: how might we use imperfect near-term quantum computers to solve problems of practical value? We…

Quantum Physics · Physics 2023-08-29 Phillip W. K. Jensen , Peter D. Johnson , Alexander A. Kunitsa

The utility of solving the Fermi-Hubbard model has been estimated in the billions of dollars. Digital quantum computers can in principle address this task, but have so far been limited to quasi one-dimensional models. This is because of…

Simulations of quantum transport in coherent conductors have evolved into mature techniques that are used in fields of physics ranging from electrical engineering to quantum nanoelectronics and material science. The most efficient…

Mesoscale and Nanoscale Physics · Physics 2019-12-25 Mathieu Istas , Christoph Groth , Xavier Waintal

The Fermi-Hubbard model is a plausible target to be solved by a quantum computer using the variational quantum eigensolver algorithm. However, problem sizes beyond the reach of classical exact diagonalisation are also beyond the reach of…

Quantum Physics · Physics 2020-06-22 Ashley Montanaro , Stasja Stanisic

Integral form of the space-time-fractional Schr\"odinger equation for the scattering problem in the fractional quantum mechanics is studied in this paper. We define the fractional Green's function for the space-time fractional Schrodinger…

Mathematical Physics · Physics 2013-02-26 Dong Jianping

In quantum field theory, the Green function is usually calculated as the expectation value of the time-ordered product of fields over the vacuum. In some cases, especially in degenerate systems, expectation values over general states are…

High Energy Physics - Theory · Physics 2010-09-15 Christian Brouder

We present an efficient numerical approach for treating ballistic quantum transport across devices described by tight binding (TB) Hamiltonians designated to systems with localized potential defects. The method is based on the wave function…

Mesoscale and Nanoscale Physics · Physics 2016-09-08 K. Kolasiński , A. Mreńca-Kolasińska , B. Szafran

Green's functions in Physics have proven to be a valuable tool for understanding fundamental concepts in different branches, such as electrodynamics, solid-state and many -body problems. In quantum mechanics advanced courses, Green's…

Physics Education · Physics 2022-10-05 William J. Herrera , Herbert Vinck-Posada , Shirley Gomez Paez

Gibbs sampling from continuous real-valued functions is a challenging problem of interest in machine learning. Here we leverage quantum Fourier transforms to build a quantum algorithm for this task when the function is periodic. We use the…

Quantum Physics · Physics 2024-07-23 Arsalan Motamedi , Pooya Ronagh

We present \texttt{lcg\_plus}, an open-source Python library for the simulation of continuous-variable quantum circuits with both generaldyne and photon-number-resolving detector capabilities. Our framework merges the linear combination of…

Quantum Physics · Physics 2025-08-11 Olga Solodovnikova , Ulrik L. Andersen , Jonas S. Neergaard-Nielsen

We introduce a fast algorithm for computing volume potentials - that is, the convolution of a translation invariant, free-space Green's function with a compactly supported source distribution defined on a uniform grid. The algorithm relies…

Numerical Analysis · Mathematics 2016-08-24 Felipe Vico , Leslie Greengard , Miguel Ferrando

We calculate the local Green function for a quantum-mechanical particle with hopping between nearest and next-nearest neighbors on the Bethe lattice, where the on-site energies may alternate on sublattices. For infinite connectivity the…

The one-dimensional time-independent Green's function $G_0$ of a quantum simple harmonic oscillator system ($V_0(x)=m \omega^2 x^2/2$) can be obtained by solving the equation directly. It has a compact expression, which gives correct…

Quantum Physics · Physics 2017-12-05 Chun-Khiang Chua , Yu-Tsai Liu , Gwo-Guang Wong

We compute the Green's functions for scalars, fermions and vectors in the color field associated with the infinite momentum frame wavefunction of a large nucleus. Expectation values of this wavefunction can be computed by integrating over…

High Energy Physics - Phenomenology · Physics 2011-07-19 Larry McLerran , Raju Venugopalan

An efficient calculation method is proposed for the face centered cubic (FCC) lattice Green function. The method is based on binomial expansion theorems, which is provide us establish analytical formulae through simple basic integrals. The…

Mathematical Physics · Physics 2012-05-08 B. A. Mamedov