Yi-Min Liu

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.

MULTIPARTY QUANTUM SECRET SHARING SCHEME OF CLASSICAL MESSAGES BY SWAPPING QUDIT-STATE ENTANGLEMENT

A multiparty quantum secret sharing scheme based on Bell-state entanglement swapping [Z. J. Zhang and Z. X. Man (2005)] is generalized to the qutrit case, that is, with qutrit-pair entangled states we propose a multiparty quantum secret sharing (QSS) scheme of classical messages by swapping qutrit-state entanglement. The security of our scheme is analyzed and confirmed with respect to some attacks. Compared to the scheme being generalized, this scheme possesses the distinct advantages of higher code capacity and higher security. Moreover, the generalization of the scheme to the qudit case is also outined.

TRIPARTITION OF ARBITRARY SINGLE-QUBIT QUANTUM INFORMATION BY USING ASYMMETRIC FOUR-QUBIT W STATE

In this paper we propose a four-party scheme for a sender to achieve the tripartition of his/her arbitrary single-qubit quantum information among three recipients via an asymmetric four-qubit W state as quantum channels. In the scheme, if and only if, the three recipients cooperate together, they can perfectly retrieve the senders quantum information by performing first two 2-qubit collective unitary operations and then a single-qubit unitary operation. The scheme is symmetric with respect to the reconstruction for any recipient can conclusively recover the quantum information with the other twos helps.

A QUANTUM SPLITTING SCHEME OF ARBITRARY TWO-QUBIT STATE USING FOUR-QUBIT CLUSTER STATE

In this paper, we explore the channel capacity of the 4-qubit 4-term cluster state (i.e. (|0000〉 + |0011〉 + |1100〉 - |1111〉)/2) for splitting arbitrary two-qubit quantum information. After our extensive investigations, we found that 4 out of 12 possible distributions of the 4 qubits can be utilized to realize bipartite splitting. In terms of each distribution, the corresponding splitting scheme is presented and LOCCs (local operation and classical communication) are explicitly given.

GENERALIZED THREE-PARTY QUBIT OPERATION SHARING

Two three-party schemes of qubit operation sharing proposed by Zhang and Cheung [J. Phys. B44 (2011) 165508] are generalized by utilizing partially entangled states as quantum channels instead of maximally entangled ones. Their quantum and classical resource consumptions, necessary-operation complexities, success probabilities and efficiencies are calculated and compared with each other. Moreover, it is revealed that the success probabilities are completely determined by the shared entanglement.

REVISITING NASERI'S SECURE QUANTUM SEALED-BID AUCTION

The secure quantum sealed-bid auction protocol [Mosayeb Naseri, Opt. Commun.282 (2009) 1939] is revisited. It is found that, utilizing intercept-measure-resend attacks, any evil bidder can make the auction aborted without being detected by the auctioneer. Further, if the evil bidder succeeds to be the first bidder, then he/she can win conclusively in the auction. To prevent such attacks, some defence strategies are adopted in the qubit distribution stage and the channel security check stage respectively and the original protocol is therefore modified somewhat.

SYMMETRIC AND PROBABILISTIC MULTIPARTY REMOTE STATE PREPARATION VIA THE POSITIVE-OPERATOR-VALUED MEASURE

We present a tripartite scheme for a preparer to remotely prepare an arbitrary single-qubit state in either distant ministrants place by using a GHZ-type state. After the preparers single-qubit state projective measurement, by performing a proper positive operator-valued measure, one ministrant can construct the preparers state in a probabilistic manner with the other ministrants assistance. Furthermore, we show that the remote state preparation can be achieved with a higher probability provided that the prepared state belongs to two special ensembles. Finally, we sketch the generalization of the tripartite scheme to a multiparty case.

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.

Preparation of genuinely entangled six-atom state via cavity quantum electrodynamics

A cavity quantum electrodynamics scheme for preparing a genuinely entangled state [A. Borras, et al., J. Phys. A 40 (2007) 13407] on six two-level atoms is proposed. In the scheme, the atom-cavity detuning is much bigger than the atom-cavity coupling strength and the necessary preparation time is much shorter than the Rydberg-atom lifespan. Hence the scheme has two distinct features, i.e., insensitive to the cavity decay and the atom radiation.

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.