Formation of spin and charge ordering in the extended Hubbard model during a finite-time quantum quench

TL;DR

This study explores how charge and spin orderings develop in a one-dimensional extended Hubbard model during finite-time quenches, revealing distinct regimes and entanglement dynamics that depend on the type of ordering.

Contribution

It provides a detailed analysis of the non-equilibrium dynamics and entanglement growth during finite-time interaction quenches in the extended Hubbard model, highlighting different regimes for charge and spin order formation.

Findings

Adiabatic regime depends on the type of order (CDW or SDW)

Intermediate regime shows entanglement entropy enhancement before order formation

Nearest-neighbor interactions do not significantly alter non-equilibrium behavior

Abstract

We investigate the formation of charge and spin ordering by starting from a non-interacting state and studying how it evolves in time under a Hamiltonian with finite electronic interactions. We consider the one-dimensional, half-filled extended Hubbard model, which we solve within time-dependent density matrix renormalization group. By employing linear finite-time quenches in the onsite and nearest-neighbor interactions, we find the existence of impulse, intermediate, and adiabatic regimes of time evolution. For the quenches we analyze, we observe that the adiabatic regime is reached with distinct ramping time scales depending on whether the charge density wave (CDW) or the spin density wave (SDW) is formed. The former needs to be slower than the latter to prevent entangled excited states from being accessed during the quench. More interestingly, in the intermediate regime, we observe an enhancement of the entanglement entropy with respect to its initial value, which precedes the formation of the CDW ordering; a similar enhancement is not seen in the quench towards SDW. Our findings also show that the breaking of the system integrability, by turning on the nearest-neighbor interactions, does not give rise to significant changes in the non-equilibrium behavior within the adiabatic approximation.