Control of spatial correlations between Rydberg excitations using rotary echo

TL;DR

This paper demonstrates how a rotary-echo technique can control and enhance spatial correlations between Rydberg excitations in cold atom samples, with implications for quantum simulation and information processing.

Contribution

It introduces a rotary-echo method to manipulate Rydberg excitation correlations and characterizes its effects on spatial pair correlations and excitation statistics.

Findings

Enhanced pair correlations at nearest-neighbor distances with phase flip at pulse midpoint

Elimination of uncorrelated atoms, increasing correlated pairs

Distinct behaviors observed in on-resonance and off-resonance conditions

Abstract

We manipulate correlations between Rydberg excitations in cold atom samples using a rotary-echo technique. The correlations are due to interactions between the Rydberg atoms. In the rotary-echo excitation sequence, the phase of the excitation pulse is flipped at a selected time during the pulse. We measure the resultant change in the spatial pair correlation function of the excitations via direct position-sensitive atom imaging. For zero detuning of the lasers from the interaction-free Rydberg-excitation resonance, the pair-correlation value at the most likely nearest-neighbor Rydberg-atom distance is substantially enhanced when the phase is flipped at the middle of the excitation pulse. In this case, the rotary echo eliminates most uncorrelated (un-paired) atoms, leaving an abundance of correlated atom pairs at the end of the sequence. In off-resonant cases, a complementary behavior is observed. We further characterize the effect of the rotary-echo excitation sequence on the excitation-number statistics of the atom sample.