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APS » Journals » Phys. Rev. Lett. » Volume 102 » Issue 21
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Phys. Rev. Lett. 102, 210402 (2009) [4 pages]

Localized Closed Timelike Curves Can Perfectly Distinguish Quantum States

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Todd A. Brun1, Jim Harrington2, and Mark M. Wilde1,3
1Communication Sciences Institute, Department of Electrical Engineering, University of Southern California, Los Angeles, California 90089, USA
2Applied Modern Physics (P-21), MS D454, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
3Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543

Received 7 November 2008; published 27 May 2009

See accompanying Physics Focus

We show that qubits traveling along closed timelike curves are a resource that a party can exploit to distinguish perfectly any set of quantum states. As a result, an adversary with access to closed timelike curves can break any prepare-and-measure quantum key distribution protocol. Our result also implies that a party with access to closed timelike curves can violate the Holevo bound.

© 2009 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.102.210402
DOI:
10.1103/PhysRevLett.102.210402
PACS:
03.65.Wj, 03.67.Dd, 03.67.Hk, 04.20.Gz
 
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