Spin squeezing in optical lattice clocks via lattice-based QND measurements

TL;DR

This paper proposes a method to enhance optical lattice clock precision by using lattice-based quantum non-demolition measurements to generate spin squeezing, reducing quantum projection noise without inducing clock shifts.

Contribution

It introduces a theoretical approach utilizing the lattice laser field for ideal QND measurements in optical clocks, enabling significant noise reduction through motional sideband detection.

Findings

Detection of motional sideband signals exceeds projection noise by a factor of 100.

Lattice-based QND measurements can suppress quantum projection noise in optical clocks.

The approach avoids clock shifts and decoherence during measurement.

Abstract

Quantum projection noise will soon limit the best achievable precision of optical atomic clocks based on lattice-confined neutral atoms. Squeezing the collective atomic pseudo-spin via measurement of the clock state populations during Ramsey interrogation suppresses the projection noise. We show here that the lattice laser field can be used to perform ideal quantum non-demolition measurements without clock shifts or decoherence and explore the feasibility of such an approach in theory with the lattice field confined in a ring-resonator. Detection of the motional sideband due to the atomic vibration in the lattice wells can yield signal sizes a hundredfold above the projection noise limit.