Nonequilibrium Pump-Probe Photoexcitation as a Tool for Analyzing Unoccupied Equilibrium States of Correlated Electrons

TL;DR

This paper proposes a pump-probe photoexcitation method to analyze unoccupied equilibrium states in correlated electrons, revealing that unoccupied spectra can be identified through their faster relaxation, challenging traditional thermalization assumptions.

Contribution

It introduces a novel experimental approach to detect unoccupied spectra in doped-Mott insulators using nonequilibrium relaxation dynamics.

Findings

Unoccupied spectra relax faster than occupied ones.

Effective temperatures differ during relaxation, invalidating thermalization assumptions.

Unoccupied states at equilibrium can be identified through their rapid relaxation.

Abstract

Relaxation of electrons in a Hubbard model coupled to a dissipative bosonic bath is studied to simulate the pump-probe photoemission measurement. From this insight, we propose an experimental method of eliciting unoccupied part of the single-particle spectra at the equilibrium of doped-Mott insulators. We reveal first that effective temperatures of distribution functions and electronic spectra are different during the relaxation, which makes the frequently employed thermalization picture inappropriate. Contrary to the conventional analysis, we show that the unoccupied spectra at equilibrium can be detected as the states that relax faster.