Probing the optical conductivity of trapped charge-neutral quantum gases

Abstract

We study a harmonically confined atomic gas which is subjected to an additional external potential such as an optical lattice. Using a linear response formulation, we determine the response of the gas to a small, time-dependent displacement of the harmonic trap and derive a simple exact relation showing that the centre-of-mass position of the atomic cloud is directly related to the global optical conductivity of the system. We demonstrate the usefulness of this approach by calculating the optical conductivity of bosonic atoms in an optical lattice. In the Mott insulating phase, there is clear evidence of an optical Mott gap, providing a proof-of-principle demonstration that the global optical conductivity gives high-quality information about the exci- tations of strongly-correlated quantum gases.

6 pages, 2 figures. Published version

References in corpus (6)

• Quantum phase transition from a superfluid to a Mott insulator in a gas of ultracold atoms
• Using photoemission spectroscopy to probe a strongly interacting Fermi gas
• Universal Quantum Viscosity in a Unitary Fermi Gas
• Observation of Quantized Conductance in Neutral Matter
• Phenomenology of the normal state in-plane transport properties of high-$T_c$ cuprates
• Phase-slip induced dissipation in an atomic Bose-Hubbard system

Cited by in corpus (8)

• Intrinsic Anomalous Hall Effect in a Bosonic Chiral Superfluid
• Lieb's Theorem and Maximum Entropy Condensates
• Optical spin transport theory of spin-1/2 topological Fermi superfluids
• Optical spin conductivity in ultracold quantum gases
• Intrinsic anomalous Hall effect across the magnetic phase transition of a spin-orbit-coupled Bose-Einstein condensate
• Spin conductivity spectrum and spin superfluidity in a binary Bose mixture
• Dynamical conductivity of disordered quantum chains
• Emergence of Sound in a Tunable Fermi Fluid