Negative quench induced excitation dynamics for ultracold bosons in one-dimensional lattices

TL;DR

This paper investigates the non-equilibrium excitation dynamics of ultracold bosons in one-dimensional lattices following interaction and lattice potential quenches, revealing control schemes for specific excitation modes like the cradle and breathing modes.

Contribution

It introduces a detailed analysis of excitation modes after negative quenches in ultracold bosonic systems, highlighting the role of incommensurate fillings and lattice depth modulations.

Findings

Cradle mode excited only for incommensurate fillings after negative interaction quench.

Lattice depth quench enables cradle mode excitation for fillings less than unity.

Fidelity analysis reveals system's dynamical response to parameter changes.

Abstract

The nonequilibrium dynamics following a quench of strongly repulsive bosonic ensembles in one-dimensional finite lattices is investigated by employing interaction quenches and/or a ramp of the lattice potential. Both sudden and time-dependent quenches are analyzed in detail. For the case of interaction quenches we address the transition from the strong repulsive to the weakly-interacting regime, suppressing in this manner the heating of the system. The excitation modes such as the cradle process and the local breathing mode are examined via local density observables. In particular, the cradle mode is inherently related to the initial delocalization and, following a negative interaction quench, can be excited only for incommensurate setups with filling larger than unity. Alternatively, a negative quench of the lattice depth which favors the spatial delocalization is used to access the cradle mode for setups with filling smaller than unity. Our results shed light on possible schemes to control the cradle and the breathing modes. Finally, employing the notion of fidelity we study the dynamical response of the system after a diabatic or adiabatic parameter modulation for short and long evolution times. The evolution of the system is obtained numerically using the ab-initio multi-layer multi-configuration time-dependent Hartree method for bosons which permits to follow non-equilibrium dynamics including the corresponding investigation of higher-band effects.