Quench spectroscopy for Lieb-Liniger bosons in the presence of harmonic trap

TL;DR

This study demonstrates the application of quench spectroscopy to one-dimensional Lieb-Liniger bosons in a harmonic trap, revealing phase distinctions and practical insights for experimental implementations.

Contribution

It extends quench spectroscopy to trapped systems, comparing experimental results with simulations, and clarifies spectral features in different quantum phases.

Findings

Broadened band signals in Mott insulator phase due to harmonic confinement

Clear spectral distinction between Mott insulator and superfluid phases

Inverse quench with larger amplitude provides the clearest spectrum

Abstract

Quench spectroscopy has emerged as a novel and powerful technique for probing the energy spectrum of various quantum phases for quantum systems from out-of-equilibrium dynamics. While its efficacy has been demonstrated in the homogeneous systems theoretically, most experimental setups feature a confining potential, such as a harmonic trap, which complicates the practical implementations. In this work, we experimentally probe the quench spectroscopy for one-dimensional bosons in optical lattices with the presence of a harmonic trap, and comparing our results with the density matrix renormalization group simulation. For the Mott insulator phase, although a gap is still observed, the band signal is broadened along the frequency space and cut at the half Brillouin zone, which can be explained by the nearest-neighbor tunneling excitations under harmonic confinement. Comparing with the superfluid spectrum, we can see a clear distinction between the two phases and find the inverse quench with larger amplitude yields the clearest spectrum. Our work offers pivotal insights into conducting quench spectroscopy effectively in practical systems.