Nuclear spin effects in optical lattice clocks

Abstract

International audienceWe present a detailed experimental and theoretical study of the effect of nuclear spin on the performance of optical lattice clocks. With a state-mixing theory including spin-orbit and hyperfine interactions, we describe the origin of the S01−P03 clock transition and the differential g factor between the two clock states for alkaline-earth-metal(-like) atoms, using Sr87 as an example. Clock frequency shifts due to magnetic and optical fields are discussed with an emphasis on those relating to nuclear structure. An experimental determination of the differential g factor in Sr87 is performed and is in good agreement with theory. The magnitude of the tensor light shift on the clock states is also explored experimentally. State specific measurements with controlled nuclear spin polarization are discussed as a method to reduce the nuclear spin-related systematic effects to below 10−17 in lattice clocks

Ultracold Fermi gases with emergent SU(N) symmetry

“…The first demonstration of this technique was achieved using the ultra-narrow 1 S 0 -3 P 0 transition in an optical lattice clock [32] operated with a cool (at temperature of a few µK) but not quantum degenerate 87 Sr gas. The 1 S 0 -3 P 0 is only allowed (laser light couples weakly to the clock states) because in the excited state, the hyperfine interaction leads to a small admixture of the higher-lying P states [87]. This small admixture strongly affects the magnetic moment, so that the nuclear g factor of the excited state significantly differs from that of the ground state (i.e ∼ 50% for strontium).…”

“…Two of them are bosonic 86 Sr and 88 Sr with relative abundance ≈ 9.9% and ≈ 82.6% respectively and one fermionic 87 Sr with ≈ 7.0% and a nuclear spin…”

Collective modes in a two-band superfluid of ultracold alkaline-earth-metal atoms close to an orbital Feshbach resonance

“…This realizes the so-called SU (N ) symmetries, where N is the number of nuclear spin components [8][9][10][11][12][13][14][15]. The OFR relies on the atoms residing on both the s and p-states which possess slight different Landé g-factors [16,17], thus allowing tuning by external magnetic field. …”

Manipulating nanoscale atom–atom interactions with cavity QED

“…[57]. Actually 3 P 1 is not pure spin-orbit LS coupling, but a mixture of higher lying 1 P 1 state such that [58],…”