Electronic double-excitations in quantum wells: solving the two-time Kadanoff-Baym equations

TL;DR

This paper investigates correlation effects in quantum wells by solving the two-time Kadanoff-Baym equations, revealing how double-excitations influence nonequilibrium properties through real-time Green's function propagation.

Contribution

It introduces a full two-time solution approach for the Kadanoff-Baym equations in quantum wells, comparing results with Hartree-Fock and exact methods to analyze correlation effects.

Findings

Full two-time Green's function solutions reveal correlation-induced double-excitations.

Comparison with Hartree-Fock and exact diagonalization validates the approach.

Results show significant correlation effects on the absorption spectrum.

Abstract

For a quantum many-body system, the direct population of states of double-excitation character is a clear indication that correlations importantly contribute to its nonequilibrium properties. We analyze such correlation-induced transitions by propagating the nonequilibrium Green's functions in real-time within the second Born approximation. As crucial benchmarks, we compute the absorption spectrum of few electrons confined in quantum wells of different width. Our results include the full two-time solution of the Kadanoff-Baym equations as well as of their time-diagonal limit and are compared to Hartree-Fock and exact diagonalization data.