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Viewpoint: Sharing Entanglement without Sending It

Christine Silberhorn

Three new experiments demonstrate how entanglement can be shared between distant parties without the need of an entangled carrier.

Dec 4, 20130 citations

Continuous-variable multiparty quantum key agreement based on third party

Yi‐Hua Zhou, Jing Zhang, Wei‐Min Shi +2 more

General quantum key agreement (QKA) protocols require each participant to make the same contribution to the generation of a shared key, but this situation cannot meet the needs of government or military which require a third party only to control key agreement process. This paper proposed a continuous-variable quantum key agreement (CVQKA) protocol with multi-party Greenberg–Horne–Zeilinger (GHZ) entangled states generated by a third party. The third party prepares quantum states by sending multi-photon beam with higher emission frequency and stronger signal. Taking continuous variable as carrier, the information carried by each carrier increases, which improves the security key rate. In this paper, the third party controls but does not contribute to the final key. After receiving the states, each participant encodes his or her own key, adds a decoy state and sends it to the next participant, until receiving the quantum state that was encoded by all the participants. Then, participants can measure and calculate to get the final shared key. It shows that our protocol is easy to implement and has high efficiency. Security analysis shows that our protocol can resist collusion attacks, beam splitter attack, etc.General quantum key agreement (QKA) protocols require each participant to make the same contribution to the generation of a shared key, but this situation cannot meet the needs of government or military which require a third party only to control key agreement process. This paper proposed a continuous-variable quantum key agreement (CVQKA) protocol with multi-party Greenberg–Horne–Zeilinger (GHZ) entangled states generated by a third party. The third party prepares quantum states by sending multi-photon beam with higher emission frequency and stronger signal. Taking continuous variable as carrier, the information carried by each carrier increases, which improves the security key rate. In this paper, the third party controls but does not contribute to the final key. After receiving the states, each participant encodes his or her own key, adds a decoy state and sends it to the next participant, until receiving the quantum state that was encoded by all the participants. Then, participants can measure and calculate to get the final shared key. It shows that our protocol is easy to implement and has high efficiency. Security analysis shows that our protocol can resist collusion attacks, beam splitter attack, etc.

Modern Physics Letters BFeb 3, 202010 citations

Quantum secret sharing without entanglement

Guo-Ping Guo, Guang-Can Guo

arXiv:quant-ph/0212056Physics Letters AApr 1, 2003358 citations

A classical analogue of negative information

Jonathan Oppenheim, Robert W. Spekkens, Andreas Winter

Recently, it was discovered that the `quantum partial information' needed to merge one party's state with another party's state is given by the conditional entropy, which can be negative [Horodecki, Oppenheim, and Winter, Nature 436, 673 (2005)]. Here we find a classical analogue of this, based on a long known relationship between entanglement and shared private correlations: namely, we consider a private distribution held between two parties, and correlated to a reference system, and ask how much secret communication is needed for one party to send her distribution to the other. We give optimal protocols for this task, and find that private information can be negative - the sender's distribution can be transferred and the potential to send future distributions in secret is gained through the distillation of a secret key. An analogue of `quantum state exchange' is also discussed and one finds cases where exchanging a distribution costs less than for one party to send it. The results give new classical protocols, and also clarify the various relationships between entanglement and privacy.Recently, it was discovered that the `quantum partial information' needed to merge one party's state with another party's state is given by the conditional entropy, which can be negative [Horodecki, Oppenheim, and Winter, Nature 436, 673 (2005)]. Here we find a classical analogue of this, based on a long known relationship between entanglement and shared private correlations: namely, we consider a private distribution held between two parties, and correlated to a reference system, and ask how much secret communication is needed for one party to send her distribution to the other. We give optimal protocols for this task, and find that private information can be negative - the sender's distribution can be transferred and the potential to send future distributions in secret is gained through the distillation of a secret key. An analogue of `quantum state exchange' is also discussed and one finds cases where exchanging a distribution costs less than for one party to send it. The results give new classical protocols, and also clarify the various relationships between entanglement and privacy.

arXiv:quant-ph/0511247Nov 28, 200543 citations

Long-distance quantum link generates entanglement faster than it is lost

Ronald Hanson, Tracy E. Northup

NatureMar 25, 20260 citations

Quantum Channels that cannot Transmit Quantum Correlations can Generate Quantum Entanglement from Classical Correlation

László Gyöngyösi, Sándor Imre

Bulletin of the American Physical SocietyJun 7, 20130 citations

Sharing Entanglement without Sending It

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Sharing Entanglement without Sending It

Abstract

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