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### Event Number 5095

**Atomic Physics Seminar****Few and many-body dynamics of Rydberg excitations in a lattice****Time:**10:00 am**Place:**5280 Chamberlin Hall**Speaker:**Dr. David Petrosyan , Institute of Electronic Structure and Lasers, FORTH, Heraklion, Crete, Greece**Abstract:**Strong, long-range, resonant and dispersive dipole-dipole interactions between the atoms in high-lying Rydberg states makes them uniquely suited to simulate and study various spin-lattice models. In this seminar, I will discuss two proposals [1,2] to implement spin chains with interesting properties using Rydberg atoms in a lattice.

I will show that an XXZ spin model with strong nearest-neighbor interactions and tunable long-range hopping of excitations can be realized by a regular array of laser driven atoms, with an excited Rydberg state representing the spin-up state and a Rydberg-dressed ground state corresponding to the spin-down state [1]. This scheme permits the observation of coherent quantum dynamics of spin excitations - magnons, their scattering and exotic interaction-bound states.

I will next describe a lattice of Rydberg superatoms - collections of atoms in microtraps that can each accommodate at most one Rydberg excitation. The coupling of superatoms to the laser radiation is collectively enhanced and they can represent mesoscopic, strongly polarizable spins. We studied a regular array of such effective spins driven by a laser field tuned to compensate the interaction-induced level shifts between the neighboring superatoms [2]. After the initial transient with resonantly facilitated excitation of large clusters of superatoms, the system relaxes to the steady state having nearly universal excitation density of 2/3. This state is characterized by highly-nontrivial equilibrium dynamics of quasi-particles â€“ excitation holes in the lattice of Rydberg excited superatoms.

[1] F. Letscher, D. Petrosyan, Phys. Rev. A 97, 043415 (2018)

[2] F. Letscher, D. Petrosyan, M. Fleischhauer, New J. Phys. 19, 113014 (2017)**Host:**SAFFMAN- Add this event to your calendar