An SU(6) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling

By S. Taie, R. Yamazaki, S. Sugawa, Y. Takahashi. Nature Physics, 2012

295 citations recorded by the source corpus.

The Hubbard model accounts for many of the diverse phenomena observed in solid-state materials, despite incorporating only nearest-neighbour hopping and on-site interactions for correlated electrons. One interesting extension to the model involves enlarging its spin symmetry to , which describes systems with orbital degeneracy. Here we report a successful formation of the SU(6) symmetric Mott-insulator state with an atomic Fermi gas of ytterbium (173Yb) atoms in a three-dimensional optical lattice. In addition to the suppression of compressibility and the charge-excitation gap characteristic of a Mott-insulating phase, we reveal that the SU(6) system can achieve lower temperatures than the SU(2) state, owing to differences in the entropy carried by an isolated spin. The mechanism is analogous to Pomeranchuk cooling in solid 3He and will be helpful for investigating exotic quantum phases of the SU() Hubbard system at extremely low temperatures. A multicomponent gas of ytterbium atoms accommodates more entropy in its spin degrees of freedom than does its two-component analogue, leading to a lower effective temperature, and an easy route for cooling ultracold fermions towards a Mott-insulating state.

Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics

View Paper: https://www.semanticscholar.org/paper/1af2b6bafb2a708a3381bebd8c13a587de894255

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Citations in the corpus

Tracking the Footprints of Spin Fluctuations: A MultiMethod, MultiMessenger Study of the Two-Dimensional Hubbard Model (2020, background): “[94] S.”
A one-dimensional liquid of fermions with tunable spin (2014, background): “In parallel, ultracold two-electron atoms have been recently proposed for the realization of large-spin systems with SU(N) interaction symmetry [19, 20], and first experimental investigations have been reported [21].”
Quantum simulation of the Hubbard model with ultracold fermions in optical lattices (2018, unknown): “The latter gives access to systems with a large number of internal states (κ = 6) and, correspondingly, to SU (6) fermionic Mott insulators [71].”
Lattice gauge theory simulations in the quantum information era (2016, background): “[116], many paradigmatic system Hamiltonians have been realized in these systems, including SU(2) [117, 118] and SU(N) fermionic Hubbard models [119–121], long-range interactions [122–124], and static gauge fields [125–129], just to name a few.”
Direct Probing of the Mott Crossover in the SU(N) Fermi-Hubbard Model (2015, methodology): “In the strongly interacting regime, the low-tunnelling model is obtained using a high-temperature series expansion (HTSE) of the grand canonical potential up to second order in t/kBT [16, 17, 26]:”
Fermi gases in one dimension: From Bethe ansatz to experiments (2013, background): “More recently they (Taie et al., 2012) have successfully realized the SU(6) symmetric Mott-insulator state with the atomic Fermi gas of 173Yb in a 3D optical lattice.”