Genuine Entangled State Research Articles

An Efficient Quantum Sealed Bidding Auction Scheme Based on the Correlation of Genuine Five-Qubit Entangled State

In this paper, an efficient quantum sealed bidding auction scheme based on genuine five-qubit entangled state is proposed. The scheme utilizes the correlation of quantum entangled states to transmit bidding information. It can use an entangled state to transmit two bits of bidding information, which greatly improves the transmission efficiency. In order to avoid collusion between bidders and auctioneer, we introduce a semi-trusted third party Trent. His supervision during the whole auction process can help participants trust each other and reduce the possibility of internal attacks. Finally, the security of the scheme is proved, and the scheme is more economical and feasible.

Circular Controlled Quantum Teleportation by a Genuine Seven-qubit Entangled State

A scheme of circular controlled quantum teleportation, which is a novel version of bidirectional controlled quantum teleportation, is proposed using a specific genuine seven-qubit entangled state as quantum channel, and then it is generalized to the scene with a general genuine seven-qubit entangled state as channel. This means that with the control of the supervisor Daniel while Alice teleportates an unknown qubit state to Bob, Bob can also teleportate an unknown qubit state to Charlie and Charlie can also teleportate an unknown qubit state to Alice circularly, simultaneously. Compared with the BCQT schemes proposed before, the intrinsic efficiency of our scheme is optimal.

Bidirectional controlled quantum teleportation by a genuine entangled 9-qubit state

Since the first protocol of quantum teleportation based on an EPR pair was presented by Bennett et al. in 1993, it has become a hot topic in quantum communication. It is known that entanglement plays a key role in quantum teleportation. Various schemes of controlled quantum teleportation and bidirectional controlled quantum teleportation have been developed by using all kinds of multi-parties entangled states as a quantum channel, e.g. GHZ states, W states, 5-qubit cluster states, 6-qubit cluster states, 7-qubit cluster states, maximally entangled 5-qubit states, maximally entangled 6-qubit states, genuine entangled 6-qubit states, genuine entangled 7-qubit states, genuine entangled 8-qubit states. In this paper, a genuine entangled 9-qubit state is used as channel of quantum teleportation, and two schemes of bidirectional controlled quantum teleportation are proposed. One scheme is that with the control of Charlie Alice can transmit an arbitrary unknown qubit state to Bob and Bob can transmit an arbitrary unknown 3-qubit state to Alice in the same time. Another scheme is that with the control of Charlie Alice and Bob can transmit an arbitrary unknown 2-qubit to each other simultaneously. Compared with the existed schemes, our scheme can transmit more qubits of arbitrary state in total by an entangled state, and the intrinsic efficiency of our scheme is maybe the best. Moreover, the genuine entangled 9-qubit state used in our scheme can be produced through some simple quantum unitary gates.

A Proxy Blind Signature Scheme of Quantum Information Transmission in Two-Particle State

A new proxy blind signature scheme based on controlled quantum teleportation is presented in this paper. We present a scheme for teleporting an unknown two-particle entangled state with message from a sender (Alice) to a receiver (David) via a genuine six-qubit entangled state. In this scheme, we introduce a trusted third party to enhance security and effectively resist forgery attacks. One-way hash faction, Von-Neumann measurement and unitary operation are adapted in this scheme. Our scheme uses the physical characteristics of quantum mechanics to implement delegation, signature and verification. Moreover, quantum key distribution (QKD) protocol and one-time pad are adapted in this scheme.

Controlled teleportation of an arbitrary two-qubit entanglement in noises environment

We present a scheme for implementing tripartite controlled teleportation of an arbitrary two-qubit entanglement state with the genuine pentaqubit entangled state and generate the quantum channel and then demonstrated the feasibility of probabilistic controlled teleportation in cavity QED. We also used fidelity and concurrence to quantify the efficiency of the protocol in noisy environment. Several noise scenarios are investigated in which the bit of the controller and the receiver are subjected to the same or different types of noise. The result has shown that in some specially noise scenario, lower fidelity means higher entanglement for output state and it also exhibits more noise which leads to more efficiency for entanglement.

Entanglement Classification for a Three-qubit System using Special Unitary Groups, SU(2) and SU(4)

Entanglement is a physical phenomenon that links a pair, or a set of particles that correlates with each other, regardless of the distance between them. Recent researches conducted on entanglement are mostly focused on measurement and classification in multiqubit systems. Classification of two qubits will only distinguish the quantum state as either separable or entangled, and it can be done by measurement. Meanwhile, in a three-qubit system, it becomes more complex because of the structure of the three qubits itself. It is not sufficient to do measurement because the states are divided into three types, including fully separable state, biseparable state, and genuine entangled state. Therefore, the classification is needed to distinguish the type of states in the three-qubit system. This study aims to classify the entanglement of three-qubit pure states using a combination model of special unitary groups, SU(2) and SU(4), by changing the angle of selected parameters in SU(4) and acting on the separable pure state. The matrix represents SU(2) is 2×2 matrix while matrix for SU(4) is 4×4 matrix. Hence, the combination of SU(2) and SU(4) represent 8×8 matrix. This classification uses the von Neumann entropy and three tangle measurements to classify the class, respectively. The results of this study have indicated that the three-qubit pure state has been successfully classified into different classes, namely, A-B-C, A-BC, C-AB, GHZ, and W, with A-B-C being a fully separable state, A-BC and C-AB are biseparable states, and GHZ and W are genuine entangled states. The results show that this model can change separable pure states to other entanglement class after transformation is done.

Quantum Private Comparison Protocols With a Number of Multi-Particle Entangled States

Private comparison allows n(n ≥ 2) participants who do not trust each other to compare whether their secret data are the same, without leaking the secret data of their own. Quantum private comparison (QPC) uses quantum mechanics to accomplish the comparison. In this paper, we present a simple and effective method which can design QPC protocols based on multi-particle entangled states including the genuinely entangled five-qubit state, the generalized Brown state, the genuine six-qubit entangled state, etc. We take the Bell state and the genuinely entangled five-qubit state as examples, respectively, to present two QPC protocols, where a semi-honest third party who assists two participants in implementing the protocols is assumed. A key feature of our protocols is that quantum states are prepared by two participants rather than by the third party, which effectively prevents the third party from preparing fake quantum states, thus improving the security of the protocols. In addition, we use the entanglement properties of multi-particle entangled states and collaborative computing between participants for privacy protection, and we use QKD to ensure the security of the cooperative computing when two participants are in different locations. We show that the security of our protocols towards both outsider and insider attacks can be guaranteed.

A New Quantum Proxy Signature Model Based on a Series of Genuine Entangled States

Quantum proxy signature(QPS) is one of the most important topics in quantum signature. In this paper, we propose a new and general model of QPS based on genuine entangled Nj-qubit (3 ≤ Nj ≤ 6,Nj ∈ N∗,j = 1,2,3,4.) states. In our model, only the teleportation of multiparty entangled states and quantum one-time pad(QOTP) encryption algorithm have been applied to ensure the security. We hope our results will be helpful to the research of quantum signature in future.

Exact Entanglement Dynamics in Three Interacting Qubits**Supported by the National Natural Science Foundation of China under Grant No 11534014, and the National Key R&D Program of China under Grant No 2017YFA0304500.

Motivated by recent experimental studies on coherent dynamics transfer in three interacting atoms or electron spins [Phys. Rev. Lett 114 (2015) 113002, Phys. Rev. Lett 120 (2018) 243604], here we study entanglement entropy transfer in three interacting qubits. We analytically calculate time evolutions of wave function, density matrix and entanglement of the system. We find that initially entangled two qubits may alternatively transfer their entanglement entropy to other two qubit pairs. Thus dynamical evolution of three interacting qubits may produce a genuine three-partite entangled state through entanglement entropy transfers. In particular, different pairwise interactions of the three qubits endow symmetric and asymmetric evolutions of the entanglement transfer, characterized by the quantum mutual information and concurrence. Finally, we discuss an experimental proposal of three Rydberg atoms for testing the entanglement dynamics transfer of this kind.

Localizable entanglement as a necessary resource of controlled quantum teleportation

We analyze the controlled teleportation protocol through three-qubit mixed states. In particular, we investigate the relation between the faithfulness of the controlled teleportation scheme and entanglement. While our knowledge concerning controlled teleportation and entanglement in pure states is well established, for mixed states it is considerably much harder task and very little has been done in this field. Here, we present counterintuitive results that provide a new light on controlled teleportation protocol. It is shown that even mixed biseparable states are useful for this protocol along with genuine entangled three-qubit states.

Secure simultaneous dense coding using $$\chi $$ χ -type entangled state

A violation of a Bell inequality can formally be expressed as a witness for quantum nonlocality. A new four-qubit Bell inequality is optimally violated by $$\chi $$ -type entangled state, but not by four-qubit GHZ, W and cluster state. Hence, $$\chi $$ -type entangled state is a good candidate to implement simultaneous dense coding. In this paper, we propose a simultaneous dense coding protocol with genuine four-particle entangled state, $$\chi $$ -type entangled state, in which two receivers can simultaneously obtain their respective classical information sent by a sender. The double controlled-NOT operator, which is used as the locking operator, play a crucial role in our protocol. The security of simultaneous dense coding is analyzed against the intercept-resend attack. The preparation of $$\chi $$ -type entangled state has been studied in various physics systems, and it has been experimentally generated with nearly deterministic scheme and high generation rate. Thus, our protocol is feasible with the current experimental technology.

Intercept-Resend-Measure Attack Towards Quantum Private Comparison Protocol Using Genuine Four-Particle Entangled States and its Improvement

Recently, Jia et al. proposed the quantum private comparison protocol with the genuine four-particle entangled states (Jia et al., Int. J. Theor. Phys. 51(4), 1187–1194 (2012)). Jia et al. claimed that in this protocol, TP cannot obtain Alice and Bob’s secrets and only knows their comparison result. However, in this paper, we demonstrate that if TP is a genuine semi-honest third party, he can totally obtain Alice and Bob’s secrets by launching a particular intercept-resend-measure attack. After suggesting the intercept-resend-measure attack strategy from TP first, we put forward one corresponding improvement to prevent this attack.

An Improved Quantum Proxy Blind Signature Scheme Based on Genuine Seven-Qubit Entangled State

An improved quantum proxy blind signature scheme based on controlled teleportation is proposed in this paper. Genuine seven-qubit entangled state functions as quantum channel. We use the physical characteristics of quantum mechanics to implement delegation, signature and verification. Security analysis shows that our scheme is unforgeability, undeniability, blind and unconditionally secure. Meanwhile, we propose a trust party to provide higher security, the trust party is costless.

A Quantum Proxy Blind Signature Scheme Based on Genuine Five-Qubit Entangled State

In this paper, a quantum proxy blind signature scheme based on controlled quantum teleportation is proposed. This scheme uses a genuine five-qubit entangled state as quantum channel and adopts the classical Vernam algorithm to blind message. We use the physical characteristics of quantum mechanics to implement delegation, signature and verification. Security analysis shows that our scheme is valid and satisfy the properties of a proxy blind signature, such as blindness, verifiability, unforgeability, undeniability.

Theoretically extensible quantum digital signature with starlike cluster states

Chen et al. (Phys Rev A 73:012303, 2006) constructed this "starlike cluster" state, which involves one qubit located at the center and n neighboring two-qubit arms. This genuine entangled state has been used for the construction of 2D and 3D cluster states, topological one-way computation, and dynamical quantum secret sharing. In this paper, we investigate the usefulness of this starlike cluster state and propose a theoretically extensible quantum digital signature scheme. The proposed scheme can be theoretically generalized to more than three participants. Moreover, it retains the merits of no requirements such as authenticated quantum channels and long-term quantum memory. We also give a security proof for the proposed scheme against repudiation and forgery.

A Quantum Multi-proxy Multi-blind-signature Scheme Based on Genuine Six-Qubit Entangled State

In this paper, a very efficient and secure multi-proxy multi-blind-signature scheme is proposed which is based on controlled quantum teleportation. Genuine six-qubit entangled state functions as quantum channel. The scheme uses the physical characteristics of quantum mechanics to guarantee its unforgeability, undeniability, blindness and unconditional security.

General monogamy of Tsallisq-entropy entanglement in multiqubit systems

In this paper, we study the monogamy inequality of Tsallis-q entropy entanglement. We first provide an analytic formula of Tsallis-q entropy entanglement in two-qubit systems for $\frac{5-\sqrt{13}}{2}\leq q\leq\frac{5+\sqrt{13}}{2}.$ The analytic formula of Tsallis-q entropy entanglement in $2\otimes d$ system is also obtained and we show that Tsallis-q entropy entanglement satisfies a set of hierarchical monogamy equalities. Furthermore, we prove the squared Tsallis-q entropy entanglement follows a general inequality in the qubit systems. Based on the monogamy relations, a set of multipartite entanglement indicators is constructed, which can detect all genuine multiqubit entangled states even in the case of $N$-tangle vanishes. Moreover, we study some examples in multipartite higher-dimensional system for the monogamy inequalities.

Teleportation of a general two-photon state employing a polarization-entangled $$\chi $$ χ state with nondemolition parity analyses

Employing a polarization-entangled $$\chi $$ź state, which is a four-photon genuine entangled state, we propose a protocol teleporting a general two-photon polarization state. Firstly, the sender needs to perform one Controlled-NOT gate, one Hadamard gate, and one Controlled-NOT gate on the state to be teleported in succession. Secondly, the sender performs local nondemolition parity analyses based on cross-Kerr nonlinearities and publicizes the achieved outcomes. Finally, conditioned on the sender's analysis outcomes, the receiver executes the single-photon unitary transformation operations on his own photons to obtain the state originally sit in the sender's location. Due to the employment of nondemolition parity analyses rather than four-qubit joint measurement, it can be realized more feasible with currently available technologies. Moreover, the resources of Bell states can be achieved because the nondestructive measurement is exploited, which facilitates other potential tasks of quantum information processing.

Classification of multipartite systems featuring only and genuine entangled states

We present several multipartite quantum systems featuring the same type of genuine (tripartite) entanglement. Based on a geometric interpretation of the so-called and states we show that the classification of all multipartite systems featuring those and only those two classes of genuine entanglement can be deduced from earlier work of algebraic geometers. In this paper, non-entangled pure states are identified with the highest weight orbit of the SLOCC group acting on the corresponding Hilbert space.

A Voting Protocol Based on the Controlled Quantum Operation Teleportation

Based on the controlled quantum operation teleportation, a secure voting protocol is proposed in this paper. Genuine four-qubit entangled state functions as the quantum channel. The eligible voter’s quantum operation which represents his vote information can be transmitted to the tallyman Bob with the help of the scrutineer Charlie. Voter’s quantum identity authentication provides the anonymity of voters’ID, which is ensured by a zero-knowledge proof of the notary organization CA. Charlie’s supervision in the whole voting process can make the protocol satisfy verifiability and non-reusability so as to avoid Bob’s dishonest behaviour. The security analysis shows that the voting protocol satisfies unforgeability, and has great advantages over some relevant researches. Additionally, the quantum operation can be transmitted successfully with the probability 1, which can make the protocol reliable and practical.