Entanglement-Enhanced Optical Atomic Clocks

TL;DR

This paper reviews how entanglement enhances optical atomic clocks, discusses experimental methods for creating entangled states, and explores protocols to surpass the Standard Quantum Limit in quantum metrology.

Contribution

It introduces recent entanglement generation techniques and time-reversal protocols that enable optical atomic clocks to operate beyond the Standard Quantum Limit.

Findings

Entanglement improves clock precision beyond SQL.

Time-reversal protocols achieve high quantum Fisher information.

Potential to reach near-Heisenberg limited metrology.

Abstract

Recent developments in atomic physics have enabled the experimental generation of many-body entangled states to boost the performance of quantum sensors beyond the Standard Quantum Limit (SQL). This limit is imposed by the inherent projection noise of a quantum measurement. In this perspective article, we describe the commonly used experimental methods to create many-body entangled states to operate quantum sensors beyond the SQL. In particular, we focus on the potential of applying quantum entanglement to state-of-the-art optical atomic clocks. In addition, we present recently developed time-reversal protocols that make use of complex states with high quantum Fisher information without requiring sub-SQL measurement resolution. We discuss the prospects for reaching near-Heisenberg limited quantum metrology based on such protocols.