A Universal Protocol for Quantum-Enhanced Sensing via Information Scrambling

TL;DR

This paper presents a universal protocol, butterfly metrology, that leverages quantum information scrambling via forward and reverse evolution to achieve Heisenberg-limited sensing with generic many-body Hamiltonians, broadening quantum sensing platforms.

Contribution

It introduces a new quantum sensing protocol based on information scrambling, enabling scalable, Heisenberg-limited measurements using local quantum interactions.

Findings

Achieves Heisenberg-limited sensitivity through information scrambling.

Demonstrates feasibility in solid-state spin defect ensembles.

Provides numerical blueprints for scalable quantum sensing.

Abstract

We introduce a novel protocol, which enables Heisenberg-limited quantum-enhanced sensing using the dynamics of any interacting many-body Hamiltonian. Our approach - dubbed butterfly metrology - utilizes a single application of forward and reverse time evolution to produce a coherent superposition of a "scrambled" and "unscrambled" quantum state. In this way, we create metrologically-useful long-range entanglement from generic local quantum interactions. The sensitivity of butterfly metrology is given by a sum of local out-of-time-order correlators (OTOCs) - the prototypical diagnostic of quantum information scrambling. Our approach broadens the landscape of platforms capable of performing quantum-enhanced metrology; as an example, we provide detailed blueprints and numerical studies demonstrating a route to scalable quantum-enhanced sensing in ensembles of solid-state spin defects.