Nonequilibrium Dynamics in a Quantum Spin Chain with Pump-Probe Resonant Inelastic X-ray Scattering

TL;DR

This paper demonstrates how time-resolved resonant inelastic X-ray scattering (tr-RIXS) can be used to probe the nonequilibrium dynamics and quantum critical behavior of a transverse field Ising chain, revealing detailed transient states and phase transitions.

Contribution

It introduces a novel application of tr-RIXS to analyze nonequilibrium quantum dynamics and identifies signatures of dynamical quantum phase transitions in spectral features.

Findings

Identification of two-kink continua at high energies.

Oscillatory spectral weight at low energies linked to quantum phase transitions.

Demonstration of tr-RIXS as a tool for detecting dynamical quantum critical points.

Abstract

We investigate the nonequilibrium dynamics of the transverse field Ising chain (TFIC) using time-resolved resonant inelastic X-ray scattering (tr-RIXS) in a pump-probe setup within a condensed matter setting. The tr-RIXS spectra reveal distinctive features, including two-kink continua at high energies and oscillatory spectral weight at low energies, both strongly influenced by the pump dynamics. By systematically analyzing the nonequilibrium tr-RIXS cross section under various pump configurations, we demonstrate how the spectra encode detailed information about the system's transient states, capturing instantaneous Hamiltonian parameters and the traversal of equilibrium quantum critical points during dynamic evolution. Notably, we uncover a one-to-one correspondence between oscillatory features in the low-energy spectra and dynamical quantum phase transitions, offering a novel and experimentally accessible approach for their detection. These findings highlight the versatility of tr-RIXS as a powerful tool for studying quantum systems far from equilibrium and their critical phenomena.