Xue-Qin Zuo

MINIMAL CLASSICAL COMMUNICATION COST AND MEASUREMENT COMPLEXITY IN SPLITTING TWO-QUBIT QUANTUM INFORMATION VIA ASYMMETRIC W STATES

We propose a scheme for splitting a two-qubit quantum information by using two asymmetric W states as quantum channel. In this scheme the split state is assumed to be completely known by the sender. Because of this, during the splitting process, the sender only needs to perform a two-qubit projective measurement. Once the sender announces the measurement result in terms of the prior agreement, then using this message the two receivers can recover the quantum information via their mutual assistance. We calculate the success probability and classical communication cost of the scheme. In general, the splitting success probability (SSP) is 1/4 and the average classical communication cost is 0.25 bit. However, we find that for some states the SSP can reach 0.5 or even unity after consuming a little additional classical resource.

TELEPORTING AND SPLITTING ARBITRARY SINGLE-QUBIT INFORMATION USING A CLASS OF THREE-QUBIT W STATES

Using a class of three-qubit W states as quantum channel, we present a quantum teleportation (QT) scheme and a quantum information splitting (QIS) scheme, respectively. We compare our schemes with two similar schemes proposed recently. It is found that our QT scheme reduces the operation difficulty in contrast to Agrawal and Patis QT scheme [Phys. Rev. A74 (2006) 062320], and our QIS scheme is more applicable than Zhengs QIS scheme [Phys. Rev. A74 (2006) 054303] for the latter is only a special case of the former in some given conditions.

QUANTUM STATE SPLITTING WITH YEO–CHUA GENUINE ENTANGLED STATE

Utilizing the four-qubit genuine entangled state presented by Yeo and Chua [Phys. Rev. Lett.96 (2006) 060502], we propose a tripartite quantum state splitting scheme for a sender to achieve the bipartition of his/her arbitrary two-qubit pure state between two sharers. During the scheme design, two novel and important ideas originated, respectively, from Phys. Rev. A74 (2006) 054303 and J. Phys. B41 (2008) 145506 are adopted to enhance the security and optimize resource consumption, operation complexity, and intrinsic efficiency. In the scheme, first the sender performs two Bell-state measurements and publishes the results. Afterwards, if and only if the two sharers cooperate together, they can perfectly restore the senders quantum pure state by executing first a two-qubit collective unitary operation and then two single-qubit unitary operations.

QUANTUM INFORMATION SPLITTING OF TWO-QUBIT STATE WITH MINIMAL CLASSICAL COMMUNICATION AND MEASUREMENT COMPLEXITY

We present a quantum information splitting scheme of a two-qubit state by using two Greenberger–Horne–Zeilinger (GHZ) states as quantum channels. In this scheme, since the sender Alice knows the quantum information in priori, she only needs to perform a two-qubit measurement and publish two classical bits for her two agents Bob and Charlie to reconstruct the quantum information via their mutual assistance. We calculate the success probability and classical communication cost within the scheme. In the general case, Alice can successfully split the state with probability 25% (probabilistic) and the classical communication cost is 4 classical bits. However, in some special cases, the secret states are chosen from a special ensemble, the success probability of our scheme can be increased to 50% or even to 100% (deterministic) after consuming some extra classical bits.