Lattice modulation spectroscopy of one-dimensional quantum gases: Universal scaling of the absorbed energy
Résumé
Lattice modulation spectroscopy is a powerful tool for probing low-energy excitations of interacting many-
body systems. By means of bosonization we analyze the absorbed power in a one-dimensional interacting
quantum gas of bosons or fermions, subjected to a periodic drive of the optical lattice. For these Tomonaga-
Luttinger liquids we find a universal ω^3 scaling of the absorbed power, which at very low-frequency turns
into an ω^2 scaling when scattering processes at the boundary of the system are taken into account. We
confirm this behavior numerically by simulations based on time-dependent matrix product states. Furthermore,
in the presence of impurities, the theory predicts an ω^2 bulk scaling. While typical response functions of
Tomonaga-Luttinger liquids are characterized by exponents that depend on the interaction strength, modulation
spectroscopy of cold atoms leads to a universal power-law exponent of the absorbed power. Our findings can be
readily demonstrated in ultracold atoms in optical lattices with current experimental technology.
