Many-body effects in momentum-space lattices

Dean Lee

Yongqiang Li, Han Cai, Da‐Wei Wang +3 more

Collective excitations of long-lived atomic hyperfine states can be synthesized into a Bose-Hubbard model in momentum space, where a spatially long-range interaction is introduced by laser-dressing the hyperfine state to Rydberg states. We explore stationary and dynamical properties of the momentum-space lattice in an artificial magnetic field. The many-body ground states support both chiral and anti-chiral edge currents in momentum space. Their stability against strong interactions is verified by a dynamical mean-field simulation. We show that the interplay of the interaction and chirality leads to correlated chiral dynamics, where an interaction-induced excitation blockade in momentum space suppresses the edge currents. When incorporating an effective decay to the lattice, we find that excitation transportation, whose dynamics is governed by a dissipative Bose-Hubard model, can be prohibited by a strong local dissipation, as a result of the quantum Zeno effect. Our study paves the route to quantum simulate topological phases and exotic dynamics with collective states of interacting atoms in momentum-space lattice.

Fangzhao Alex An, Η. Meier, Jackson Ang’ong’a +1 more

We study the influence of atomic interactions on quantum simulations in momentum-space lattices (MSLs), where driven transitions between discrete momentum states mimic transport between sites of a synthetic lattice. Low-energy atomic collisions, which are short ranged in real space, relate to nearly infinite-ranged interactions in momentum space. However, the added exchange energy between atoms in distinguishable momentum states leads to an effectively attractive, finite-ranged interaction between atoms in momentum space. In this Letter, we observe the onset of self-trapping driven by such interactions in a momentum-space double well, paving the way for more complex many-body studies in tailored MSLs. We consider the types of phenomena that may result from these interactions, including the formation of chiral solitons in zigzag flux lattices.

Lingzhen Guo

Paulo F. Bedaque

Yongqiang Li, Han Cai, Da‐Wei Wang +3 more

Collective excitations (spin waves) of long-lived atomic hyperfine states can be synthesized into a Bose-Hubbard model in momentum space. We explore many-body ground states and dynamics of a two-leg momentum-space lattice formed by two coupled hyperfine states. Essential ingredients of this setting are a staggered artificial magnetic field engineered by lasers that couple the spin wave states and a state-dependent long-range interaction, which is induced by laser dressing a hyperfine state to a Rydberg state. The Rydberg dressed two-body interaction gives rise to a state-dependent blockade in momentum space and can amplify staggered flux-induced antichiral edge currents in the many-body ground state in the presence of magnetic flux. When the Rydberg dressing is applied to both hyperfine states, exotic sliding insulating and superfluid (supersolid) phases emerge. Because of the Rydberg dressed long-range interaction, spin waves slide along a leg of the momentum-space lattice without costing energy. Our study paves a route to the quantum simulation of topological phases and exotic dynamics with interacting spin waves of atomic hyperfine states in momentum-space lattice.