Continuous symmetry breaking in a trapped-ion spin chain.

Feng, Lei; Katz, Or; Haack, Casey; Maghrebi, Mohammad; Gorshkov, Alexey V; Gong, Zhexuan; Cetina, Marko; Monroe, Christopher · Nature · 2023

basic_science · Level V

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Abstract

One-dimensional systems exhibiting a continuous symmetry can host quantum phases of matter with true long-range order only in the presence of sufficiently long-range interactions<sup>1</sup>. In most physical systems, however, the interactions are short-ranged, hindering the emergence of such phases in one dimension. Here we use a one-dimensional trapped-ion quantum simulator to prepare states with long-range spin order that extends over the system size of up to 23 spins and is characteristic of the continuous symmetry-breaking phase of matter<sup>2,3</sup>. Our preparation relies on simultaneous control over an array of tightly focused individual addressing laser beams, generating long-range spin-spin interactions. We also observe a disordered phase with frustrated correlations. We further study the phases at different ranges of interaction and the out-of-equilibrium response to symmetry-breaking perturbations. This work opens an avenue to study new quantum phases and out-of-equilibrium dynamics in low-dimensional systems.