Bragg spectroscopy of clean and disordered lattice bosons in one dimension: a spectral fingerprint of the Bose glass

Abstract

We study the dynamic structure factor of a one-dimensional Bose gas confined in an optical lattice and modeled by the Bose-Hubbard Hamiltonian, using a variety of numerical and analytical approaches. The dynamic structure factor, experimentally measurable by Bragg spectroscopy, is studied in three relevant cases: in the clean regime, featuring either a superfluid or a Mott phase; and in the presence of two types of (quasi-)disordered external potentials: a quasi-periodic potential obtained from a bichromatic superlattice and a random-box disorder - both featuring a Bose glass phase. In the clean case, we show the emergence of a gapped doublon mode (corresponding to a repulsively bound state) for incommensurate filling, well separated from the low-energy acoustic mode. In the disordered case, we show that the dynamic structure factor provides a direct insight into the spatial structure of the excitations, unveiling their localized nature, which represents a fundamental signature of the Bose glass phase. Furthermore, it provides a clear fingerprint of the very nature of the localization mechanism which differs for the two kinds of disorder potentials we consider. In special cases, the dynamic structure factor may provide an estimate of the position of the localization transition from superfluid to Bose glass, in a complementary manner to the information deduced from the momentum distribution.

26 pages, 12 figures (low resolution): v2; corrected x-axis scale in Fig. 6

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Cited by in corpus (15)

• Drive Induced Delocalization in Aubry-André Model
• Localization transition in weakly-interacting Bose superfluids in one-dimensional quasiperdiodic lattices
• Topological spin excitations in Harper-Heisenberg spin chains
• Dynamical structure factor of one-dimensional hard rods
• Quantum phases of incommensurate optical lattices due to cavity backaction
• Magnetic responses of randomly depleted spin ladders
• Bosons with incommensurate potential and spin-orbit coupling
• Finding the phase diagram of strongly-correlated disordered bosons using quantum quenches
• Quench Spectroscopy of a Disordered Quantum System
• Matter-wave scattering from interacting bosons in an optical lattice
• A finite temperature study of ideal quantum gases in the presence of one dimensional quasi-periodic potential
• Bose-Hubbard model with random impurities: Multiband and nonlinear hopping effects
• Emergence of damped-localized excitations of the Mott state due to disorder
• Numerical study of the temperature dependence of the NMR relaxation rate across the superfluid-Bose glass transition in one dimension
• Time-dependent variational Monte Carlo study of the dynamic response of bosons in an optical lattice