Multi-band spectroscopy of inhomogeneous Mott-insulator states of ultracold bosons

TL;DR

This paper employs inelastic light scattering to explore the excitation spectrum and dispersion relations of inhomogeneous Mott-insulator states of ultracold bosons, revealing detailed band and momentum characteristics.

Contribution

It introduces a band-mapping technique to identify band and momentum of excited atoms in Mott insulators using inelastic light scattering.

Findings

Identification of energy absorption linked to experimental parameters

Observation of linear response to light scattering

Reconstruction of dispersion relations in high energy bands

Abstract

In this work, we use inelastic scattering of light to study the response of inhomogeneous Mott-insulator gases to external excitations. The experimental setup and procedure to probe the atomic Mott states are presented in detail. We discuss the link between the energy absorbed by the gases and accessible experimental parameters as well as the linearity of the response to the scattering of light. We investigate the excitations of the system in multiple energy bands and a band-mapping technique allows us to identify band and momentum of the excited atoms. In addition the momentum distribution in the Mott states which is spread over the entire first Brillouin zone enables us to reconstruct the dispersion relation in the high energy bands using a single Bragg excitation with a fixed momentum transfer.