Inelastic light scattering to probe strongly correlated bosons in optical lattices
Authors: Fort C., Fabbri N., Fallani L., Clément D., Inguscio M.
Autors Affiliation: European Laboratory for Nonlinear Spectroscopy (LENS), Nello Carrara 1, 50019 Sesto Fiorentino (FI), Italy; Dipartimento di Fisica e Astronomia, Universit di Firenze, vai Sansone 1, 50019 Sesto Fiorentino (FI), Italy; C.N.I.S.M., UdR di Firenze, Italy; INO-CNR, Italy
Abstract: We have used inelastic light scattering to study correlated phases of an array of one-dimensional interacting Bose gases. In the linear response regime, the observed spectra are proportional to the dynamic structure factor. In particular we have investigated the superfluid to Mott insulator crossover loading the one-dimensional gases in an optical lattice and monitoring the appearance of an energy gap due to finite particle-hole excitation energy. We attribute the low frequency side of the spectra to the presence of some superfluid and normal phase fraction between the Mott insulator regions with different fillings produced in the inhomogeneous systems. In the Mott phase we also investigated excitations to higher excited bands of the optical lattice, the spectra obtained in this case being connected to the single particle spectral function. In one-dimensional systems the effect of thermal fluctuations and interactions is enhanced by the reduced dimensionality showing up in the dynamic structure factor. We measured the dynamic structure factor of an array of one-dimensional bosonic gases pointing out the effect of temperature-induced phase fluctuations in reducing the coherence length of the system.
Conference title: ICAP2010 – XXII International Conference on Atomic Physics
Place: Cairns, Tropical North Queensland, Australia
KeyWords: Atomic physics; Bosons; Crystal lattices; Light scattering; Optical materials, Dynamic structure factors; Effect of temperature; Inelastic light scattering; Inhomogeneous system; One-dimensional systems; Single-particle spectral function; Strongly correlated bosons; Thermal fluctuations, Optical latticesDOI: 10.1088/1742-6596/264/1/012018