Practical roadmap to measurement-altered criticality in Rydberg arrays

TL;DR

This paper presents a practical method to experimentally realize and control measurement-induced changes in quantum critical properties of Rydberg atom chains, enabling new insights into quantum phase transitions.

Contribution

It introduces a feasible scheme for observing measurement-altered criticality in Rydberg arrays, with a focus on controlling correlations through selective measurements and post-processing.

Findings

Measurement outcomes with large probabilities induce significant changes in critical correlations.

The protocol requires minimal experimental overhead, making it accessible for current quantum simulation platforms.

Post-measurement states can be characterized by adjusted data analysis without additional hardware.

Abstract

Weak measurements have been predicted to dramatically alter universal properties of quantum critical wavefunctions, though experimental validation remains an open problem. Here we devise a practical scheme for realizing measurement-altered criticality in a chain of Rydberg atoms tuned to Ising and tricritical Ising phase transitions. In particular, we show that projectively measuring a periodic subset of atoms alters quantum critical correlations in distinct ways that one can control via the choice of measured sites and the measurement outcomes. While our protocol relies on post-selection, the measurement outcomes yielding the most dramatic consequences occur with surprisingly large probabilities: O(10%) with chains featuring O(100) sites. Characterizing the proposed post-measurement states requires only an adjustment in the post-process averaging of outcomes used to characterize unmeasured critical states, resulting in minimal additional experimental overhead for demonstrating measurement-altered criticality.