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World's First Demonstration of Bit Commitment Performed at CQT

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apparatus for creating entangled photon pairs

A group at the National University of Singapore's Center for Quantum Technologies built this table-top apparatus for creating entangled photon pairs.

Credit: Center for Quantum Technologies

Computer scientists and quantum optics researchers at the University of Singapore's Center for Quantum Technologies (CQT) have demonstrated secure bit commitment, a communication system for users who do not trust each other. The researchers used hundreds of thousands of entangled photon pairs in the demonstration. Bit commitment is similar to submitting a sealed bid in a house auction.

In their demonstration, the researchers harness some of the behaviors associated with quantum mechanics to guarantee secure bit commitment. The method involves an entangled photon source and detection kit used for previous quantum cryptography demonstrations. Although the CQT method can only store a few qubits, the researchers showed that a 250,000-photon exchange would be secure against a memory of 972 qubits suffering a certain noise. If quantum memories get bigger, security could be restored by increasing the waiting time or boosting the total number of bits sent, according to the researchers.

"Theoretical protocols currently outstrip experimental capabilities by several decades and if I am to live to own a quantum laptop, these kind of collaborative efforts are a must," says CQT's Siddarth Joshi.

From National University of Singapore
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Abstracts Copyright © 2013 Information Inc., Bethesda, Maryland, USA


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