Photoinduced coherent oscillations in the one-dimensional two-orbital Hubbard model

TL;DR

This paper investigates ultrafast coherent oscillations caused by orbital degrees of freedom in a one-dimensional two-orbital Hubbard model, revealing quantum interference effects and orbital excitations through exact numerical simulations.

Contribution

It provides the first detailed analysis of photoinduced coherent oscillations in a multi-orbital Hubbard model using numerically exact solutions.

Findings

Oscillations caused by quantum interference between photogenerated states.

Identification of orbiton-related oscillations around the charge-transfer peak.

Spectra show characteristic coherent oscillations varying with probe light frequency.

Abstract

We study photoinduced ultrafast coherent oscillations originating from orbital degrees of freedom in the one-dimensional two-orbital Hubbard model. By solving the time-dependent Schr\"odinger equation for the numerically exact many-electron wave function, we obtain time-dependent optical response functions. The calculated spectra show characteristic coherent oscillations that vary with the frequency of probe light. A simple analysis for the dominant oscillating components clarifies that these photoinduced oscillations are caused by the quantum interference between photogenerated states. The oscillation attributed to the Raman-active orbital excitations (orbitons) clearly appears around the charge-transfer peak.