Measuring the scrambling of quantum information

TL;DR

This paper introduces a protocol to measure out-of-time-order correlation functions, crucial for understanding quantum information scrambling, using cold atoms and cavity QED, with potential applications across various experimental platforms.

Contribution

It presents a practical method to measure quantum information scrambling via out-of-time-order correlators in experimental setups.

Findings

Feasibility demonstrated with cold atoms and cavity QED

Analysis of dissipation effects on measurement accuracy

Proposal for measuring correlators in multiple platforms

Abstract

We provide a protocol to measure out-of-time-order correlation functions. These correlation functions are of theoretical interest for diagnosing the scrambling of quantum information in black holes and strongly interacting quantum systems generally. Measuring them requires an echo-type sequence in which the sign of a many-body Hamiltonian is reversed. We detail an implementation employing cold atoms and cavity quantum electrodynamics to realize the chaotic kicked top model, and we analyze effects of dissipation to verify its feasibility with current technology. Finally, we propose in broad strokes a number of other experimental platforms where similar out-of-time-order correlation functions can be measured.