Interaction Quench Induced Multimode Dynamics of Finite Atomic Ensembles

TL;DR

This paper investigates the non-equilibrium dynamics of few-boson systems in finite one-dimensional lattices after a sudden interaction quench, revealing complex multimode oscillations and resonance phenomena through numerical and analytical methods.

Contribution

It introduces a detailed numerical study of quench-induced multimode dynamics in finite bosonic lattices and derives an effective Hamiltonian to explain spectral and resonant behaviors.

Findings

Observation of density-wave tunneling, breathing, and cradle modes.

Identification of resonance phenomena linked to avoided crossings.

Derivation of an effective Hamiltonian for spectral analysis.

Abstract

The correlated non-equilibrium dynamics of few-boson systems in one-dimensional finite lattices is investigated. Starting from weak interactions we perform a sudden interaction quench and employ the numerically exact Multi-Layer Multi-Configuration time-dependent Hartree method for bosons to obtain the resulting quantum dynamics. Focusing on the low-lying modes of the finite lattice we observe the emergence of density-wave tunneling, breathing and cradle-like processes. In particular, the tunneling induced by the quench leads to a "global" density-wave oscillation. The resulting breathing and cradle modes are inherent to the local intrawell dynamics and connected to excited-band states. Moreover, the interaction quenches couple the density-wave and the cradle modes allowing for resonance phenomena. These are associated with an avoided-crossing in the respective frequency spectrum and lead to a beating dynamics for the cradle. Finally, complementing the numerical studies, an effective Hamiltonian in terms of the relevant Fock states is derived for the description of the spectral properties and the related resonant dynamics.