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Title: 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}{radical}(N)){sup -1}--i.e., as the standard quantum limit. We introduce a protocol that makes use of N{sub c} coherent exchanges of a single qubit at frequency {omega}, leading to an accuracy that scales as ({omega}N{sub c}){sup -1} ln N{sub c}. 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 analyze the performance of these protocols when used with a lossy channel.0.

Authors:
 [1];  [2]
  1. School of Physical Sciences, University of Queensland, Queensland 4072 (Australia)
  2. School of Physics, University of Sydney, New South Wales 2006 (Australia)
Publication Date:
OSTI Identifier:
20718694
Resource Type:
Journal Article
Journal Name:
Physical Review. A
Additional Journal Information:
Journal Volume: 72; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevA.72.042301; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1050-2947
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ACCURACY; PERFORMANCE; QUANTUM COMPUTERS; QUANTUM ENTANGLEMENT; QUANTUM MECHANICS; QUBITS; SYNCHRONIZATION

Citation Formats

Burgh, Mark de, and Bartlett, Stephen D. Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement. United States: N. p., 2005. Web. doi:10.1103/PhysRevA.72.042301.
Burgh, Mark de, & Bartlett, Stephen D. Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement. United States. https://doi.org/10.1103/PhysRevA.72.042301
Burgh, Mark de, and Bartlett, Stephen D. 2005. "Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement". United States. https://doi.org/10.1103/PhysRevA.72.042301.
@article{osti_20718694,
title = {Quantum methods for clock synchronization: Beating the standard quantum limit without entanglement},
author = {Burgh, Mark de and Bartlett, Stephen D},
abstractNote = {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}{radical}(N)){sup -1}--i.e., as the standard quantum limit. We introduce a protocol that makes use of N{sub c} coherent exchanges of a single qubit at frequency {omega}, leading to an accuracy that scales as ({omega}N{sub c}){sup -1} ln N{sub c}. 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 analyze the performance of these protocols when used with a lossy channel.0.},
doi = {10.1103/PhysRevA.72.042301},
url = {https://www.osti.gov/biblio/20718694}, journal = {Physical Review. A},
issn = {1050-2947},
number = 4,
volume = 72,
place = {United States},
year = {Sat Oct 15 00:00:00 EDT 2005},
month = {Sat Oct 15 00:00:00 EDT 2005}
}