2-7 June 2019
Simon Fraser University
America/Vancouver timezone
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44 - Sum rule for transport dynamics of ultracold atoms in an optical lattice

Jun 4, 2019, 5:03 PM
SWH 9082 + AQ South-East Corner / coin sud-est (Simon Fraser University)

SWH 9082 + AQ South-East Corner / coin sud-est

Simon Fraser University

Poster not-in-competition (Graduate Student) / Affiche non-compétitive (Étudiant(e) du 2e ou 3e cycle) Division of Atomic, Molecular and Optical Physics, Canada / Division de la physique atomique, moléculaire et photonique, Canada (DAMOPC-DPAMPC) DAMOPC Poster Session & Student Poster Competition Finals (26) | Session d'affiches DPAMPC et finales du concours d'affiches étudiantes (26)


Mr Rhys Anderson (University of Toronto)


We observe the satisfaction of the sum rule for the conductivity of neutral fermions in an optical lattice subject to weak harmonic confinement. We measure the conductivity spectrum of the atoms through observations of the global current response to a perturbative applied force, using a quantum gas microscope. The spectrum is measured up to frequencies sufficient to characterize intraband transport, but well below the bandgap. The spectral weight of the response satisfies the sum rule in the limit of small lattice depth, but diminishes as the depth increases, reflecting an increase in the band-averaged effective mass. Measured under varying temperatures, densities, interaction strengths, and lattice depths, the spectral weight is shown to be obtainable from a thermodynamic description of the system. Furthermore, it is shown to be unaffected by varying the strength of interactions between the fermions, illustrating a fundamental prediction for conductivity spectra. The spectral weight characterizes the strength of the current response to an impulse, and therefore underpins the resistivity. As our measurements approach a high-temperature regime, its inverse is shown to approach T-linear behaviour.

Primary authors

Mr Rhys Anderson (University of Toronto) Dr Fudong Wang (South University of Science and Technology) Mr Peihang Xu (University of Toronto) Mr Vijin Venu (University of Toronto) Dr Stefan Trotzky (University of Toronto) Prof. Frederic Chevy (Laboratoire Kastler Brossel, Ecole Normale Superieure) Prof. Joseph Thywissen (University of Toronto)

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