Time-dependent Kohn-Sham theory with memory

TL;DR

This paper develops a time-dependent Kohn-Sham theory incorporating memory effects through viscoelastic stresses, enabling more accurate modeling of electron dynamics including decoherence and relaxation.

Contribution

It introduces a novel formalism that includes memory-dependent exchange-correlation potentials in time-dependent density-functional theory.

Findings

Demonstrates xc memory effects in quantum well charge oscillations

Clarifies dissipation mechanisms in electron dynamics

Extracts intersubband relaxation rates for different excitation strengths

Abstract

In time-dependent density-functional theory, exchange and correlation (xc) beyond the adiabatic local density approximation can be described in terms of viscoelastic stresses in the electron liquid. In the time domain, this leads to a velocity-dependent xc vector potential with a memory containing short- and long-range components. The resulting time-dependent Kohn-Sham formalism describes the dynamics of electronic systems including decoherence and relaxation. For the example of collective charge-density oscillations in a quantum well, we illustrate the xc memory effects, clarify the dissipation mechanism, and extract intersubband relaxation rates for weak and strong excitations.