A New Quantum Interferometric Protocol Using Spin-Dependent Displacements

TL;DR

This paper introduces a quantum interferometric protocol that uses spin-dependent displacements to achieve high-precision measurements beyond classical limits, applicable to various quantum sensing platforms.

Contribution

It presents a novel protocol combining spin and spatial degrees of freedom for enhanced quantum metrology, demonstrating Heisenberg-limited sensitivity and practical feasibility.

Findings

Achieves sub-shot-noise scaling in parameter estimation.

Demonstrates effectiveness in magnetic field sensing.

Discusses implementation in ultracold atoms and NV centers.

Abstract

We propose a quantum interferometric protocol that leverages spin-dependent spatial displacements to enable high-precision parameter estimation beyond classical limits. By inducing a unitary coupling between a particles spin degree of freedom and its momentum, the protocol generates entanglement between spin states and spatial positions, resulting in coherent spatial superpositions. Interferometric reconstruction of the resulting phase differences enables Heisenberg limited sensitivity for parameters encoded in the spin Hamiltonian. As a concrete application, we demonstrate the protocols effectiveness in magnetic field sensing, where the field is transduced into spatial interference fringes. Quantum Fisher information analysis confirms sub-shot-noise scaling, and the protocol's feasibility is discussed for physical platforms including ultracold atoms and nitrogen-vacancy (NV) centers. Our framework provides a versatile approach to quantum metrology with potential extensions to multiparameter sensing and gravitational wave detection.