Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement

Abstract

We introduce methods for clock synchronization that make use of the adiabatic exchange of nondegenerate two-level quantum systems: ticking qubits. Schemes involving the exchange of N independent qubits with frequency $\omega$ give a synchronization accuracy that scales as $(\omega \sqrt{N}{)}^{-1}$, i.e., as the standard quantum limit. We introduce a protocol that makes use of N coherent exchanges of a single qubit at frequency $\omega$, leading to an accuracy that scales as $(\omega N{)}^{-1}\log N$. This protocol beats the standard quantum limit without the use of entanglement, and we argue that this scaling is the fundamental limit for clock synchronization allowed by quantum mechanics. We analyse the performance of these protocols when used with a lossy channel.

9 pages, 1 figure, published version

References in corpus (6)

• Quantum-enhanced measurements: beating the standard quantum limit
• Distant Clock Synchronization Using Entangled Photon Pairs
• Classical and quantum communication without a shared reference frame
• Quantifying the resource of sharing a reference frame
• Conveyor belt clock synchronization
• Defending Continuous Variable Teleportation: Why a laser is a clock, not a quantum channel

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