Green’s Functions for Tight-Binding Hamiltonians

Nilanjana Datta, Roberto Fernández, Jürg Martin Fröhlich

A. P. Itin, Анатолий Исерович Нейштадт

Giulia Galli, Jeongnim Kim, Andrew Canning +1 more

Antonios Gonis

We propose a formalism for the study of many-particle interacting quantum systems that allows the determination of the Green function of the system as a whole and corresponding Green functions of lower order from a knowledge of any Green function of a higher order. We illustrate the formalism by means of calculations on a model single-band system described by a Hamiltonian of tight-binding kind and corresponding to four electrons on a ring of four sites.

N. N. Bogolyubov

Kamal Kumar Choudhary

Quantum chemistry is one of the most promising near-term applications of quantum computers. Quantum algorithms such as variational quantum eigen solver (VQE) and variational quantum deflation (VQD) algorithms have been mainly applied for molecular systems and there is a need to implement such methods for periodic solids. Using Wannier tight-binding Hamiltonian (WTBH) approaches, we demonstrate the application of VQE and VQD to accurately predict both electronic and phonon bandstructure properties of several elemental as well as multi-component solid-state materials. We apply VQE-VQD calculations for 307 spin-orbit coupling based electronic WTBHs and 933 finite-difference based phonon WTBHs. We establish a workflow for using VQD with lattice Greens function that can be used for solving dynamical mean-field theory problems. The WTBH model solvers can be used for testing other quantum algorithms also.