Quantum-Enhanced Sensing Enabled by Scrambling-Induced Genuine Multipartite Entanglement

TL;DR

This paper demonstrates a scalable quantum sensing protocol using many-body scrambling and multipartite entanglement on a superconducting quantum processor, surpassing the standard quantum limit.

Contribution

It experimentally realizes a universal, scrambling-based quantum sensing protocol, linking sensitivity enhancement to out-of-time-order correlators and multipartite entanglement.

Findings

Achieved quantum-enhanced sensitivity beyond the standard quantum limit.

Observed a sensitivity scaling consistent with twice the Heisenberg limit for up to 10 qubits.

Established a connection between sensitivity enhancement and out-of-time-order correlators.

Abstract

Quantum sensing leverages quantum resources to surpass the standard quantum limit, yet many existing protocols rely on the preparation of complex entangled states and Hamiltonian engineering, posing challenges for universality and scalability. Here, we report an experimental realization of a universal protocol, known as Butterfly Metrology, proposed in [arXiv:2411.12794], demonstrating a scrambling-based approach for quantum-enhanced sensing on a superconducting quantum processor. By exploiting many-body information scrambling, we observe quantum-enhanced sensitivity to an encoded phase beyond the standard quantum limit, with a scaling consistent with a factor-of-two of the Heisenberg limit for system sizes of up to 10 qubits. Importantly, we experimentally establish a connection between the enhanced sensitivity and the dynamics of the out-of-time-order correlator (OTOC), and show that the buildup of scrambling-induced genuine multipartite entanglement underlies the observed sensitivity enhancement. Our results demonstrate a scalable and practical approach for quantum-enhanced sensing in interacting many-body quantum systems.