Quantum frequency estimation with trapped ions and atoms

TL;DR

This paper explores quantum-enhanced methods for estimating atomic transition frequencies using trapped ions and atoms, demonstrating that decoherence-free strategies can overcome noise limitations and achieve quantum advantage.

Contribution

It introduces decoherence-free subspace techniques for quantum frequency estimation, showing they outperform standard methods under realistic experimental imperfections.

Findings

Standard Ramsey interferometry offers limited quantum improvement under collective dephasing.

Decoherence-free subspace methods enable quantum enhancement despite imperfect state preparation.

Quantum advantage is achievable even with faulty detections and significant imperfections.

Abstract

We discuss strategies for quantum enhanced estimation of atomic transition frequencies with ions stored in Paul traps or neutral atoms trapped in optical lattices. We show that only marginal quantum improvements can be achieved using standard Ramsey interferometry in the presence of collective dephasing, which is the major source of noise in relevant experimental setups. We therefore analyze methods based on decoherence free subspaces and prove that quantum enhancement can readily be achieved even in the case of significantly imperfect state preparation and faulty detections.