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Published September 15, 2022 | public
Journal Article

Quantum spin liquids bootstrapped from Ising criticality in Rydberg arrays

Abstract

Arrays of Rydberg atoms constitute a highly tunable, strongly interacting venue for the pursuit of exotic states of matter. We develop a strategy for accessing a family of fractionalized phases known as quantum spin liquids in two-dimensional Rydberg arrays. We specifically use effective field theory methods to study arrays assembled from Rydberg chains tuned to an Ising phase transition that famously hosts emergent fermions propagating within each chain. This highly entangled starting point allows us to naturally access spin liquids familiar from Kitaev's honeycomb model — albeit from an entirely different framework. In particular, we argue that finite-range repulsive Rydberg interactions, which frustrate nearby symmetry-breaking orders, can enable coherent propagation of emergent fermions between the chains in which they were born. Delocalization of emergent fermions across the full two-dimensional Rydberg array yields a gapless ℤ₂ spin liquid with a single massless Dirac cone. Here, the Rydberg occupation numbers exhibit universal power-law correlations that provide a straightforward experimental diagnostic of this phase. We further show that explicitly breaking symmetries perturbs the gapless spin liquid into gapped, topologically ordered descendants: Breaking lattice symmetries generates toric-code topological order, whereas introducing Floquet-mediated chirality generates non-Abelian Ising topological order. In the toric-code phase, we analytically construct microscopic incarnations of non-Abelian defects, which can be created and transported by dynamically controlling the atom positions in the array. Our work suggests that appropriately tuned Rydberg arrays provide a cold-atoms counterpart of solid-state "Kitaev materials" and, more generally, it spotlights a different angle for pursuing experimental platforms for Abelian and non-Abelian fractionalization.

Additional Information

It is a pleasure to thank Lesik Motrunich, David Mross, and Frederik Nathan for stimulating conversations. We are particularly grateful to Paul Fendley for many illuminating discussions and a prior collaboration that set the foundations of our study. The U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Quantum Science Center supported the construction and analysis of 2D Rydberg array models. The Army Research Office under Grant Award No. W911NF-17-1-0323 supported the analysis of non-Abelian defects. Additional support was provided by the National Science Foundation through Grant No. DMR-1848336 (R.M.); the Caltech Institute for Quantum Information and Matter, an NSF Physics Frontiers Center with support of the Gordon and Betty Moore Foundation through Grant No. GBMF1250; the Walter Burke Institute for Theoretical Physics at Caltech; the ESQ by a Discovery Grant; the Gordon and Betty Moore Foundation's EPiQS Initiative, Grant No. GBMF8682; and the AFOSR YIP (FA9550-19-1-0044). M.E. acknowledges support from the NSF QLCI program through Grant No. OMA-2016245, the DARPA ONISQ program (Grant No. W911NF2010021), and the DOE Quantum Systems Accelerator Center (Contract No. 7568717).

Additional details

Created:
August 20, 2023
Modified:
February 10, 2024