The marriage between Rydberg physics and ultracold atomic systems have hatched so many fascinating achievements. The exaggerated properties of Rydberg states, combined with the pristine environments provided by the ultracold atoms, can lead to realizations of exotic physical systems. One particularly innovative direction that emerged recently is to use microwave-frequency transitions between Rydberg levels to simulate the dynamics of a particle hopping between lattice sites. Such approach, referred to as Rydberg synthetic dimensions, falls under the broad scheme of quantum simulations. Here we present description of the infrastructure used for Rydberg excitation and coherent microwave transitions, which are essential to the realization of Rydberg synthetic dimensions. We will also present experimental results on simulating the Su-Schireffer-Heeger Hamiltonian, a canonical model with paradigmatic importance in topological physics.

Mar 5, 20250 citations

Rydberg-atom synthetic dimensions

S. K. Kanungo

Synthetic dimensions are powerful tools for quantum simulation and computation. They are realized by harnessing internal or external degrees of freedom of an atom or molecule, which can mimic the motion of an electron in a real-space lattice potential. Such degrees of freedom are highly tunable and can be engineered to create configurations difficult to access or realize in real space. Some of the exciting possibilities include realizing higher dimensions systems[1, 2, 3], nontrivial real space[4, 5] and band structure[6, 7] topologies and artificial gauge fields[8, 9]. Experiments have utilized various degrees of freedom to create synthetic dimensions, such as motional[10, 11], spin[8, 12, 13, 14] and rotational[15] levels of atoms and molecules, and frequency modes, spatial modes, and arrival times in photonic systems[16]. Atomic synthetic dimensions have demonstrated artificial gauge fields, spin-orbit coupling, chiral edge states using Raman-coupled ground magnetic sublevels[8, 12, 17] of atoms, and phenomena such as Anderson localization using two-photon Bragg transitions by coupling free-particle momentum states[18]. Here, we harness the Rydberg levels of 84Sr to realize a synthetic lattice for studying quantum matter. Resonant millimeter-wave (mm-wave) radiation coupling Rydberg levels |i⟩ and |j⟩ with amplitude Ωij (Rabi frequency) are described by the same Hamiltonian as a particle tunneling between lattice sites |i⟩ and |j⟩ with tunneling amplitude Jij = Ωij /2. The mathematical equivalence to particles moving in a real-space lattice enables Rydberg levels to function as a synthetic spatial dimension. Rydberg-atom synthetic dimensions offer control over connectivity, tunneling rates and on-site potentials, which allows for the creation of a broad range of synthetic dimensional system. The capabilities of such a system are demonstrated by realizing the famous Su-Schrieffer-Heeger (SSH) model[19] and studying its topologically protected edge states(TPS).

Sep 8, 20220 citations