TY - JOUR

T1 - Thermodynamics of a deeply degenerate SU(N)-symmetric Fermi gas

AU - Sonderhouse, Lindsay

AU - Sanner, Christian

AU - Hutson, Ross B.

AU - Goban, Akihisa

AU - Bilitewski, Thomas

AU - Yan, Lingfeng

AU - Milner, William R.

AU - Rey, Ana M.

AU - Ye, Jun

N1 - Funding Information:
We thank T. Bothwell, C. Kennedy, E. Oelker and J. Robinson for discussions and technical contributions. We also thank J. Thompson and C. Kennedy for reading the manuscript. This work is supported by NIST, DARPA, and AFOSR grant nos. FA9550-19-1-0275 and FA9550-18-1-0319, and NSF grant no. PHYS-1734006. C.S. thanks the Humboldt Foundation for support.
Publisher Copyright:
© 2020, The Author(s), under exclusive licence to Springer Nature Limited.

PY - 2020/12

Y1 - 2020/12

N2 - Many-body quantum systems can exhibit a striking degree of symmetry unparallelled in their classical counterparts. In real materials SU(N) symmetry is an idealization, but this symmetry is pristinely realized in fully controllable ultracold alkaline-earth atomic gases. Here, we study an SU(N)-symmetric Fermi liquid of 87Sr atoms, where N can be tuned to be as large as 10. In the deeply degenerate regime, we show through precise measurements of density fluctuations and expansion dynamics that the large N of spin states under SU(N) symmetry leads to pronounced interaction effects in a system with a nominally negligible interaction parameter. Accounting for these effects, we demonstrate thermometry accurate to 1% of the Fermi energy. We also demonstrate record speed for preparing degenerate Fermi seas enabled by the SU(N)-symmetric interactions, reaching T/TF = 0.22 with 10 nuclear spin states in 0.6 s working with a laser-cooled sample. This, along with the introduction of a new spin polarizing method, enables the operation of a three-dimensional optical lattice clock in the band insulating regime.

AB - Many-body quantum systems can exhibit a striking degree of symmetry unparallelled in their classical counterparts. In real materials SU(N) symmetry is an idealization, but this symmetry is pristinely realized in fully controllable ultracold alkaline-earth atomic gases. Here, we study an SU(N)-symmetric Fermi liquid of 87Sr atoms, where N can be tuned to be as large as 10. In the deeply degenerate regime, we show through precise measurements of density fluctuations and expansion dynamics that the large N of spin states under SU(N) symmetry leads to pronounced interaction effects in a system with a nominally negligible interaction parameter. Accounting for these effects, we demonstrate thermometry accurate to 1% of the Fermi energy. We also demonstrate record speed for preparing degenerate Fermi seas enabled by the SU(N)-symmetric interactions, reaching T/TF = 0.22 with 10 nuclear spin states in 0.6 s working with a laser-cooled sample. This, along with the introduction of a new spin polarizing method, enables the operation of a three-dimensional optical lattice clock in the band insulating regime.

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U2 - 10.1038/s41567-020-0986-6

DO - 10.1038/s41567-020-0986-6

M3 - Article

AN - SCOPUS:85089961204

SN - 1745-2473

VL - 16

SP - 1216

EP - 1221

JO - Nature Physics

JF - Nature Physics

IS - 12

ER -