Trapped Ultracold Bosons in Periodically Modulated Lattices

TL;DR

This paper investigates the spectral response of ultracold bosons in one-dimensional optical lattices under periodic modulation, revealing phase-specific excitations and validating the Bose-Hubbard model through advanced numerical simulations.

Contribution

It provides a detailed analysis of dynamical responses in different quantum phases using time-dependent density-matrix renormalization group methods, highlighting phase-specific features and model validation.

Findings

Identification of excitation processes in Mott insulators

Local density approximation describes superfluid response

Spectroscopic features test Bose-Hubbard model validity

Abstract

Motivated by the recent rapid development of the field of quantum gases in optical lattices, we present a comprehensive study of the spectrum of ultracold atoms in a one-dimensional optical lattice subjected to a periodic lattice modulation. Using the time-dependent density-matrix renormalization group method, we study the dynamical response due to lattice modulations in different quantum phases of the system with varying density. For the Mott insulating state, we identify several excitation processes, which provide important information about the density profile of the gases. For the superfluid, the dynamical response can be well described in a local density approximation. This simplification can be valuable in understanding the strong-correlated superfluid in a slow-varying harmonic potential. All these spectroscopic features of an inhomogeneous system can be used as a test for the validity of the Bose-Hubbard model in a parabolic trapping potential.