Probing critical phenomena in open quantum systems using atom arrays.

At continuous phase transitions, quantum many-body systems exhibit complex, emergent behavior. Most notably, at a quantum critical point, correlations decay as a power law, with exponents determined by a set of universal scaling dimensions. Experimentally probing such power law correlations is extremely challenging, owing to the interplay between decoherence, the vanishing energy gap, and boundary effects. In this work, we used a Rydberg quantum simulator to adiabatically prepare critical ground states of both a one-dimensional ring and a two-dimensional square lattice. By accounting for and tuning the openness of our quantum system, which is well-captured by a single phenomenological length scale, we directly observed power law correlations and extracted the corresponding scaling dimensions. Our work complements recent studies of quantum criticality that use the Kibble-Zurek mechanism and digital quantum circuits. Editor's summary: Quantum criticality is characterized by universal power-law decays of correlations in real space. Fang et al. observed these decays using a programmable Rydberg simulator consisting of cesium atoms arranged in ring and square lattice geometries. The researchers extracted the characteristic scaling dimensions from the exponents of the power-law decays. By tuning the degree of openness of their system, they were able to study the impact of decoherence on the nature of quantum criticality. —Jelena Stajic [ABSTRACT FROM AUTHOR]