Charge and heat transport in an atomic Fermi-Hubbard system

Benjamin M. Spar, Peter Brown, Elmer Guardado-Sanchez +3 more

Qinyuan Zheng, Kaden R. A. Hazzard, Eduardo Ibarra-García-Padilla

Matthew A. Nichols, Lawrence W. Cheuk, Melih Okan +6 more

Strongly correlated materials are expected to feature unconventional transport properties, such that charge, spin, and heat conduction are potentially independent probes of the dynamics. In contrast to charge transport, the measurement of spin transport in such materials is highly challenging. We observed spin conduction and diffusion in a system of ultracold fermionic atoms that realizes the half-filled Fermi-Hubbard model. For strong interactions, spin diffusion is driven by super-exchange and doublon-hole-assisted tunneling, and strongly violates the quantum limit of charge diffusion. The technique developed in this work can be extended to finite doping, which can shed light on the complex interplay between spin and charge in the Hubbard model.

Hui Zhai, Ning Sun, Jinlong Yu +1 more

Utilizing the Fermi gas microscope, recently the MIT group has measured the spin transport of the Fermi Hubbard model (FHM) starting from a spin-density-wave state, and the Princeton group has measured the charge transport of the FHM starting from a charge-density-wave state. Motivated by these two experiments, we prove a theorem that shows under certain conditions, the spin and charge transports can be equivalent to each other. The proof makes use of the particle-hole transformation of the FHM and a recently discovered symmetry protected dynamical symmetry. Our results can be directly verified in future cold atom experiment with the Fermi gas microscope.

B. Sriram Shastry, Edward Perepelitsky, Andrew Galatas +3 more

Elmer Guardado-Sanchez, Alan Morningstar, Benjamin M. Spar +3 more

Experiments show that a particular quantum many-body system thermalizes surprisingly slowly, and a hydrodynamic model of the system reveals a crucial underlying link between the transport of both mass and heat.