Quantum metrology with time-reversed interactions in Rydberg atom array

The precision of measurements using uncorrelated particles is limited by the standard quantum limit. Quantum-enhanced metrology can overcome this bound by exploiting entanglement, for example through spin-squeezed states that reduce quantum projection noise. Here we demonstrate enhanced spin-squeezing–based metrology using a time-reversed interaction protocol implemented in a Rydberg atom array with N=54 atoms. Collective spin states undergo nonlinear evolution governed by a dipolar XY model, are subjected to a weak perturbation, and then experience a reversed evolution that amplifies the metrological signal. We show that the detection sensitivity can be optimized by tuning the measurement axis as well as the forward and backward evolution times. Our results illustrate the potential of time-reversed interactions in Rydberg atom arrays for quantum-enhanced metrology.