Cryogenic suppression of correlated loss in Rydberg atom arrays
Blackbody radiation (BBR) poses a central challenge for quantum science with Rydberg atoms. By driving transitions to nearby opposite-parity states, BBR shortens Rydberg lifetimes and has long been suspected to trigger "avalanche" events known to cause correlated atom loss. Here, we suppress avalanche decay and establish BBR as its dominant trigger using a Rydberg atom array that operates either cryogenically or at room temperature. A $45~\text{K}$ radiation shield reduces ambient BBR, extending Rydberg $nS$ lifetimes for $n$ ranging from 50 to 75. BBR-induced decay rates are suppressed by 30%-50%, corresponding to an effective blackbody temperature $T_{\rm eff}\approx190~\text{K}$. This enables controlled comparisons of Rydberg-dressed atom arrays operating in different BBR environments. Arrays of up to 70 atoms demonstrate cryogenically suppressed avalanche rates, tracking the suppression in BBR-induced decay, for both $n=50$ and $n=60$ dressing. A parameter-free rate model agrees with the measured avalanche rates after accounting for frequency-dependent cryogenic shielding, photoionization-triggered avalanches, laser phase noise, BBR decay channels, and Rydberg interaction effects. We demonstrate a quantitative description of avalanche decay and show that improved BBR shielding should further suppress correlated loss to the $T_\text{eff}=45~\text{K}$ achievable in the current apparatus. Our results establish a route to mitigating correlated errors that otherwise impede fault-tolerant operation in neutral-atom quantum processors.