Hamiltonian engineering of spin-orbit-coupled fermions in a Wannier-Stark optical lattice clock.

Aeppli, Alexander; Chu, Anjun; Bothwell, Tobias; Kennedy, Colin J; Kedar, Dhruv; He, Peiru; Rey, Ana Maria; Ye, Jun · Sci Adv · 2022

basic_science · Level V

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Abstract

Engineering a Hamiltonian system with tunable interactions provides opportunities to optimize performance for quantum sensing and explore emerging phenomena of many-body systems. An optical lattice clock based on partially delocalized Wannier-Stark states in a gravity-tilted shallow lattice supports superior quantum coherence and adjustable interactions via spin-orbit coupling, thus presenting a powerful spin model realization. The relative strength of the on-site and off-site interactions can be tuned to achieve a zero density shift at a "magic" lattice depth. This mechanism, together with a large number of atoms, enables the demonstration of the most stable atomic clock while minimizing a key systematic uncertainty related to atomic density. Interactions can also be maximized by driving off-site Wannier-Stark transitions, realizing a ferromagnetic to paramagnetic dynamical phase transition.