Observation of two-orbital spin-exchange interactions with ultracold SU(N)-symmetric fermions
By F. Scazza, C. Hofrichter, M. Höfer, P. D. Groot, I. Bloch, S. Fölling. Nature Physics, 2014
312 citations recorded by the source corpus.
Spin-exchanging interactions govern the properties of strongly correlated electron systems such as many magnetic materials. When orbital degrees of freedom are present, spin exchange between different orbitals often dominates, leading to the Kondo effect, heavy fermion behaviour or magnetic ordering. Ultracold ytterbium or alkaline-earth ensembles have attracted much recent interest as model systems for these effects, with two (meta-) stable electronic configurations representing independent orbitals. We report the observation of spin-exchanging contact interactions in a two-orbital SU(N)-symmetric quantum gas realized with fermionic 173Yb. We find strong inter-orbital spin exchange by spectroscopic characterization of all interaction channels and demonstrate SU(N = 6) symmetry within our measurement precision. The spin-exchange process is also directly observed through the dynamic equilibration of spin imbalances between ensembles in separate orbitals. The realization of an SU(N)-symmetric two-orbital Hubbard Hamiltonian opens the route to quantum simulations with extended symmetries and with orbital magnetic interactions, such as the Kondo lattice model. Using the two stable electronic states of alkaline-earth atoms, an orbital spin-exchange interaction—the building block of orbital quantum magnetism—has been observed in a fermionic quantum gas.
Subfields: Atomic and Molecular Physics, and Optics, Condensed Matter Physics
View Paper: https://www.semanticscholar.org/paper/19214d53decc49f7e5f407360faa58770be19ae1
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In Atomic and Molecular Physics, and Optics
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Citations in the corpus
- Optical atomic clocks (2014, background): “Direct observations of this symmetric interactions have already been confirmed (Scazza et al., 2014; Zhang et al., 2014b).”
- Alkaline-Earth Atoms in Optical Tweezers (2018, background): “spectral control, unique spin properties [35,69], and orbital spin exchange interactions [36,37] has been experimentally”
- Direct Probing of the Mott Crossover in the SU(N) Fermi-Hubbard Model (2015, background): “Therefore, nuclear and electronic angular momenta are decoupled, making the atomic interactions independent of the nuclear spin state and making the system SUðNÞ symmetric, with N ≤ 2I þ 1 1⁄4 6 being the number of populated nuclear spin states [17].”