Many-body interferometry of a Rydberg-dressed spin lattice

Abstract

Ultracold atoms in optical lattices are ideal to study fundamentally new quantum many-body systems 1,2 including frustrated or topological magnetic phases 3,4 and supersolids 5,6 . However, the necessary control of strong long-range interactions between distant ground state atoms has remained a long-standing goal. Optical dressing of ground state atoms via o -resonant laser coupling to Rydberg states is one way to tailor such interactions 5-8 . Here we report the realization of coherent Rydberg dressing to implement a two-dimensional synthetic spin lattice. Our single-atom-resolved interferometric measurements of the many-body dynamics enable the microscopic probing of the interactions and reveal their highly tunable range and anisotropy. Our work marks the first step towards the use of laser-controlled Rydberg interactions for the study of exotic quantum magnets 3,4,9 in optical lattices.Neutral ultracold atoms in optical lattices are among the most promising platforms for the implementation of analog quantum simulators of condensed matter systems. However, the simulation of magnetic Hamiltonians, often emerging as an effective model in more complex many-body systems, is difficult with contact interactions due to the low energy scale of the associated superexchange process 10 . Long-range interactions offer an alternative way to directly achieve strong effective spin-spin interactions. Such interactions emerge between magnetic atoms and between ultracold polar molecules 11 , trapped ions 12 or ground state atoms resonantly 13 or off-resonantly coupled ('dressed') to Rydberg states [5][6][7][8] . Rydberg dressing is especially appealing due to the simplicity of realizing atomic lattice systems with unity filling, combined with the great tunability of the interaction strength and shape, which might be exploited to explore exotic models of quantum magnetism 3,4 . While effects of long-range spin interactions have been observed in many-body systems of polar molecules 14 , ions [15][16][17] and resonantly excited Rydberg atoms 18,19 , none of these approaches combines the advantages of Rydberg dressing, which permits the realization of strong spin interactions in lattices with near-unity filling. So far, Rydberg dressing in a many-body system remains an experimental challenge, for which up to now only dissipative effects have been measured [20][21][22][23][24] . For two atoms, first promising experimental results have been reported recently for near-resonant strong dressing 25 , where, however, the assumption of a weak Rydberg-state admixture required for the realization of various many-body models 5,6,9,26,27 does not hold 28 .Here we demonstrate Rydberg dressing in a two-dimensional (2D) near-unity-filled atomic lattice with tailored extended range interactions between approximately 200 effective spins. In contrast to our previous experiments 18,29 on resonantly coupled Rydberg gases, all atoms participate here in the spin dynamics. We exploit the temporal control over such interactions to perform interferometric ...

Discrete Time Crystals: Rigidity, Criticality, and Realizations

“…We emphasize that our proposed realization can likewise be naturally implemented in ultracold polar molecules [45,46] and Rydberg-dressed neutral atom arrays [47,48], both of which also feature long-range interactions. This leads to a key question: can the discrete time crystal survive the presence of such long-range interactions [49][50][51]?…”

Floquet Symmetry-Protected Topological Phases in Cold-Atom Systems

“…1). While the Rydberg dressing is subject to dissipation from the finite lifetime Γ −1 of the Rydberg state [43,44], the interaction-to-decay ratio can be large [49,50] in a 1D system. At fixed Rabi frequency Ω, the ratio of the Ising coupling J to the lifetime γ = (Ω 2 /4∆ 2 )Γ of the Rydberg-dressed state is limited to J/γ = Ω 2 2∆Γ < Ω Γ .…”

“…3b). In combination, this points to the fact that the two edge modes are well localized to a single site and behave like an EPR pair.Experimental realization-Both the ESPT and FSPT Hamiltonians can be implemented in a chain of Rydbergdressed alkali-metal atoms [43,44,46,49,50] trapped in a 1D optical lattice or tweezer array [83,84] (Fig. 1).…”

“…For cold atoms, where Floquet control has so far been applied only to single-particle band strucarXiv:1610.07611v3 [cond-mat.quant-gas] 22 Sep 2017 2 tures [29][30][31][37][38][39], recent advances in optically controlling interactions [40][41][42][43][44][45][46][47] offer new opportunities for accessing strongly correlated phases [48][49][50][51]. Notably, coherent spin-spin interactions with a range of several microns [42,43,46,47] can be introduced via Rydberg dressing [42-44, 46, 47, 52-55]. However, prospects for modulating such dressing light in order to Floquet engineer many-body Hamiltonians has remained largely unexplored.…”

Excitations and stability of weakly interacting Bose gases with multibody interactions

“…These potentials were recently created in optical lattices with Rb atoms excited to Rydberg states [39,40]. The interest for such interactions is general and involves the simulation of novel kinds of spin Hamiltonians [41,42] for the creation of exotic phases, like the supersolid [43][44][45][46], and for metrological applications [47][48][49][50].…”