Quantum Entanglement Swapping Research Articles

SkySwapping: Entanglement resupply by separating quantum swapping and photon exchange

We propose a fast, satellite-based, on-demand entanglement resupply protocol which leverages entangled pairs exchanged in advance between satellites and ground stations. At the request time, the protocol does not require any quantum information exchange between ground and satellite, by performing the quantum entanglement swapping on satellite-level only, thus separating the particle exchange phase. In this work we analyzed different recent approaches on the topic of satellite-based entanglement resupply and our protocol improves existing works by minimizing fidelity loss due to environmental factors regardless of the distance between requesting ground stations.

Hybrid protocols for multi-party semiquantum private comparison, multiplication and summation without a pre-shared key based on d-dimensional single-particle states

In this paper, by utilizing d-dimensional single-particle states, three semiquantum cryptography protocols, i.e., the multi-party semiquantum private comparison (MSQPC) protocol, the multi-party semiquantum multiplication (MSQM) protocol and the multi-party semiquantum summation (MSQS) protocol, can be achieved simultaneously under the assistance of two semi-honest quantum third parties (TPs). Here, the proposed MSQPC scheme is the only protocol which is devoted to judging the size relationship of secret integers from more than two semiquantum participants without a pre-shared key. And the proposed MSQM protocol absorbs the innovative concept of semiquantumness into quantum multiplication for the first time, which can calculate the modulo d multiplication of private inputs from more than two semiquantum users. As for the proposed MSQS protocol, it is the only semiquantum summation protocol which aims to accomplish the modulo d addition of more than three semiquantum users’ private integers. Neither quantum entanglement swapping nor unitary operations are necessary in the three proposed protocols. The security analysis verifies in detail that both the external attacks and the internal attacks can be resisted in the three proposed protocols.

Nonlinear Interaction between Two Chirped Broadband Single Photons

AbstractCoherent correlation between two distant broadband single photons can be realized by using the nonlinear optical method, which provides a key technology for spread‐spectrum communication in the quantum network. Here, sum‐frequency generation (SFG) between two broadband single photons is experimentally demonstrated by using chirp technology. The results show that the efficiency of the SFG is 6.51 × 10−8, and the visibility of coherent correlation of two distant broadband photons of the telecommunications band is 93.7%. This technique can also be used for other quantum applications, such as quantum entanglement swapping and quantum communication.

Multi-party semiquantum private comparison of size relationship with d-dimensional Bell states

In this paper, we utilize d-dimensional Bell states to construct a multi-party semiquantum private comparison (MSQPC) protocol with two supervisors, which can determine the size relationship of more than two classical users’ private inputs under the control of two supervisors within one round implementation. The two supervisors, i.e., one quantum third party (TP) and one classical TP, are both semi-honest, which means that they can misbehave at their own wishes but are not permitted to conspire with anyone else. Neither quantum entanglement swapping nor unitary operations are required in the proposed MSQPC protocol. The security analysis certifies that the proposed MSQPC protocol can overcome both the outside attacks and the participant attacks.

Multi-party quantum private comparison of size relationship with two third parties based on d-dimensional Bell states

In this paper, we put forward a multi-party quantum private comparison (MQPC) protocol with two semi-honest third parties (TPs) by adopting -dimensional Bell states, which can judge the size relationship of private integers from more than two users within one execution of protocol. Each TP is permitted to misbehave on her own but cannot collude with others. In the proposed MQPC protocol, TPs are only required to apply -dimensional single-particle measurements rather than -dimensional Bell state measurements. There are no quantum entanglement swapping and unitary operations required in the proposed MQPC protocol. The security analysis validates that the proposed MQPC protocol can resist both the outside attacks and the participant attacks. The proposed MQPC protocol is adaptive for the case that users want to compare the size relationship of their private integers under the control of two supervisors. Furthermore, the proposed MQPC protocol can be used in the strange user environment, because there are not any communication and pre-shared key between each pair of users.

A novel multi-party semiquantum private comparison protocol of size relationship with [formula omitted]-dimensional single-particle states

By using d-level single-particle states, the first multi-party semiquantum private comparison (MSQPC) protocol which can judge the size relationship of private inputs from more than two classical users within one execution of protocol is put forward. This protocol requires the help of one quantum third party (TP) and one classical TP, both of whom are allowed to misbehave on their own but cannot conspire with anyone else. Neither quantum entanglement swapping nor unitary operations are necessary for implementing this protocol. TPs are only required to perform d-dimensional single-particle measurements. The correctness analysis validates the accuracy of the compared results. The security analysis verifies that both the outside attacks and the participant attacks can be resisted.

Semiquantum secret sharing by using χ-type states

In this paper, a semiquantum secret sharing (SQSS) protocol based on x-type states is proposed, which can accomplish the goal that only when two classical communicants cooperate together can they extract the shared secret key of a quantum communicant. Detailed security analysis turns out that this protocol is completely robust against an eavesdropper. This protocol has some merits: (1) it only requires one kind of quantum entangled state as the initial quantum resource; (2) it doesn't employ quantum entanglement swapping or unitary operations; and (3) it needn't share private keys among different participants beforehand.

Single-state semiquantum private comparison based on Bell states

In this paper, a novel semiquantum private comparison (SQPC) protocol based on single kind of Bell states is proposed, which allows two classical parties to judge the equality of their private inputs securely and correctly under the help of a semi-honest third party (TP) who possesses complete quantum capabilities. TP is allowed to misbehave on her own but cannot conspire with anyone else. Our protocol needs none of unitary operations, quantum entanglement swapping or the reordering operations. Moreover, our protocol only needs to prepare single kind of Bell states as initial quantum resource. Detailed security analysis turns out that our protocol is secure against various outside and participant attacks. Compared with most of the existing SQPC protocols based on Bell states, our protocol is more feasible in practice.

Generation of Three-Mode Entanglement Based on Parametric Amplifiers Using Quantum Entanglement Swapping

Quantum entanglement swapping is one of the most promising quantum techniques to create or manipulate large-scale multi-mode entanglement between two distant quantum entangled systems. In this work, a scheme for the generation of three-mode entanglement based on parametric amplifiers using quantum entanglement swapping has been proposed. The newly generated three-mode entanglement is always present in the whole power gain region from parametric amplifiers and its dependence on transmission loss and feedforward gain is also investigated. In addition, the effects of power gain, transmission loss, and feedforward gain on the two-mode entanglement of the three pairs in the newly generated three-mode entanglement have also been analysed in detail. The results presented here may find some practical applications in quantum secure communication.

A lightweight three-user secure quantum summation protocol without a third party based on single-particle states

In this paper, a lightweight three-user secure quantum summation protocol is put forward by using single-particle states, which can accomplish the goal that three users cooperate together to calculate the modulo 2 addition of their private messages without the help of a third party. This protocol only requires single-particle states rather than quantum entangled states as the initial quantum resource and only needs single-particle measurements and Bell basis measurements. This protocol needs none of quantum entanglement swapping, the Pauli operations, the controlled-not (CNOT) operation, the Hadamard gate or a pre-shared private key sequence. Security analysis proves that this protocol is secure against both the outside attacks and the participant attacks. Compared with the existing two-dimensional three-user quantum summation protocols, this protocol more or less takes advantage over them on the aspects of the initial quantum resource, users’ quantum measurement, the usage of quantum entanglement swapping, the usage of Pauli operations, the usage of CNOT operation or the usage of Hadamard gate.

Entangled Coherent States in Teleportation

In the present paper, we will review the methods to produce superposition of entangled coherent state using polarizing beam splitter and Kerr non linearity. These coherent states have many attractive features and can be used in various schemes. Entanglement, refers to the superposition of a multiparticle system and explains a new type of correlations between any two subsystems of the quantum system, which is not existing in the classical physics. The present paper deals with the use of these states in quantum teleportation, entanglement diversion and entanglement swapping schemes. Entanglement diversion and entanglement-swapping refers to a scheme which may entangle those particles which had never interacted before. In the swapping scheme, two pairs of entangled state are taken. One particle from each pair is subjected to a Bell-state-measurement. This would result in projection of the other two outgoing particles in an entangled pair. Quantum Teleportation of two mode and three modes states is also studied with perfect fidelity. Minimum assured fidelity which is defined as the minimum of the fidelity for any unknown quantum information of the states is also discussed. It is also shown how the success rate of teleportation of a superposition of odd and even coherent states can be increased from 50% to almost 100%. The scheme suggested by van Enk and Hirota was modified by Prakash, Chandra, Prakash and Shivani in 2007. We find that an almost teleportation, diversion and swapping is possible by simply separating vacuum state from the even state. The present paper also deals with study of effect of decoherence and noise on these states and the effect of noise on fidelity and minimum assured fidelity. It is also discussed that these schemes can also be applied to the process of entanglement diversion and entanglement swapping.

Quantum private comparison with six-particle maximally entangled states

A novel quantum private comparison (QPC) protocol with six-particle maximally entangled states is put forward, which can guarantee that the true content of secret messages from two users cannot be extracted by an illegal party. The entanglement correlation among different particles in one six-particle maximally entangled state is taken to realize the private comparison of secret messages from two users. Neither quantum entanglement swapping nor unitary operations are adopted. Third party (TP) only needs Bell basis measurements while two users only need Bell basis measurements and [Formula: see text] basis measurements. The proposed protocol has no security loophole for the outside attack and the participant attack.

Single-state multi-party semiquantum key agreement protocol based on multi-particle GHZ entangled states

In this paper, we put forward a novel single-state three-party semiquantum key agreement (SQKA) protocol with three-particle GHZ entangled states first. Different with previous quantum key agreement (QKA) protocols, the proposed single-state three-party SQKA protocol can realize the goal that a quantum party and two classical parties who only possess limited quantum capabilities equally contribute to the generation of a shared private key over quantum channels. Detailed security analysis turns out that the proposed single-state three-party SQKA protocol is secure against several famous attacks from an outside eavesdropper, such as the Trojan horse attack, the entangle-measure attack, the measure-resend attack and the intercept-resend attack. Moreover, it can resist the participant attack, which means that the shared private key cannot be determined fully by any nontrivial subset of three parties. The proposed single-state three-party SQKA protocol has the following nice features: (1) it only employs one kind of three-particle GHZ entangled states as initial quantum resource; (2) it does not need pre-shared keys among different parties; (3) it does not need unitary operations or quantum entanglement swapping. Finally, we generalize the proposed single-state three-party SQKA protocol into the case of $$N$$ -party by only employing one kind of $$N$$ -particle GHZ entangled states as initial quantum resource, which inherits the nice features of its three-party counterpart.

一种新颖的基于类GHZ态的两方半量子密钥分配协议

In this paper, we propose a novel two-party semiquantum key distribution (SQKD) protocol by only employing one kind of GHZ-like state. The proposed SQKD protocol can create a private key shared between one quantum party with unlimited quantum abilities and one classical party with limited quantum abilities without the existence of a third party. The proposed SQKD protocol doesn't need the Hadamard gate or quantum entanglement swapping. Detailed security analysis turns out that the proposed SQKD protocol can resist various famous attacks from an outside eavesdropper, such as the Trojan horse attacks, the entangle-measure attack, the double CNOT attacks, the measure-resend attack and the intercept-resend attack.

Three-Party Secure Semiquantum Summation without Entanglement Among Quantum User and Classical Users

In this paper, a three-party secure semiquantum summation protocol, which can calculate the modulo 2 addition of the private bits from one quantum participant and two classical participants, is constructed by only using single qubits as the initial quantum resource. This protocol needs none of quantum entanglement swapping, the unitary operation or a pre-shared private key. This protocol only requires the quantum participant to perform the $$\left\{ {\left| 0 \right\rangle ,\left| 1 \right\rangle } \right\}$$ basis measurements, the $$\left\{ {\left| + \right\rangle ,\left| - \right\rangle } \right\}$$ basis measurements and the Bell basis measurements. Compared with the existing only semiquantum summation protocol (Int J Theor Phys, 60 (2021) 3478), this protocol has better performance in quantum measurements for quantum participant; moreover, it may also have higher qubit efficiency.

Multi-party Quantum Key Agreement Protocol with Authentication

Utilizing the advantage of quantum entanglement swapping, a multi-party quantum key agreement protocol with authentication is proposed. In this protocol, a semi-trusted third party is introduced, who prepares Bell states, and sends one particle to multiple participants respectively. After that the participants can share a Greenberger-Horne-Zeilinger state by entanglement swapping. Finally, these participants measure the particles in their hands and obtain an agreement key. Here, classical hash function and Hadamard operation are utilized to authenticate the identity of participants. The correlations of GHZ states ensure the security of the proposed protocol. To illustrated it detailly, the security of this protocol against common attacks is analyzed, which shows that the proposed protocol is secure in theory.

Quantum teleportation and entanglement swapping with long baseline in outer space

Quantum information (QI) experiments applying quantum optics in outer space with a very long baseline may have advantages over the current Earth-bound experiments or the Earth-to-satellite experiments, because they can minimize the loss in light transmission and maximize the gain in time resolution. This future class of experiments, among them quantum teleportation and entanglement swapping, can shed light on many fundamental theoretical issues in gravitational quantum physics and relativistic QI. Regarding relativity theory, these experiments in an outer-space setting can involve observations at spacelike and timelike separations and explicate intriguing phenomena from different choices of time-slicing. Regarding QI, they may be able to ensure the causal independence of the expectation values in the Bell test. These issues are addressed in this paper with analysis and explanations.

A key distribution protocol based on quantum entanglement swapping for unmanned surface vehicle

Aiming at the problem of Unmanned Surface Vehicle’s (USV) secure communication, this paper proposes a key distribution protocol based on quantum entanglement swapping for USV. Compared with the current techniques, this paper uses the principle of quantum unclonability and quantum entanglement in quantum mechanics to realize the secure communication of USV. Meanwhile, in view of the low visibility at sea and the influence of weather such as wind and waves, this study adopts a key distribution architecture of quantum relay to realize the establishment of quantum channel between any two ships and obtain the absolutely secure key eventually. Therefore, the proposed method can provide long-distance, secure and reliable communication for USVs in the civil and military fields.

Novel two-party quantum private comparison via quantum walks on circle

The quantum private comparison aims to make the size comparison of two participants’ private information without leaking the private data of their own with quantum mechanism. In this paper, different from the current method of using single particle or entangled state as the information carrier, a novel two-party quantum private comparison protocol is firstly proposed via quantum walks on circle. In the protocol, a third party is assumed to be semi-honest and allowed to misbehave on his own, but cannot conspire with either of the two dishonest participants and obtain the participants’ private information. The protocol adopts the two-particle quantum walks state on circle rather than entangled state as the initial quantum resource and only needs measurement and quantum walks operator without the unitary operation and quantum entanglement swapping. The two-particle state is transferred as a whole among different parties, which reduces the protocol complexity and avoids the chance of being attacked. It can implement the equality comparison of private information, but also the size comparison. Security analyses show that this protocol is resistant to the external and internal malicious attacks, which can also determine the disputes over the judgment result of the third party. Compared with other quantum private comparison protocols, the proposed protocol has better flexibility and universality.

Feasible measurement-based entanglement purification in linear optics.

Entanglement purification is used to distill high quality entangled states from several noisy low quality entangled states, and it plays a key role in quantum repeater. The measurement-based entanglement purification protocol (MB-EPP) does not require local two-qubit gates or single-particle measurements on the noisy pairs and may offer significant advantages compared with the gate-based EPPs. We present an alternative MB-EPP in linear optics. Subsequently, we provide a detailed analysis on the realization of this MB-EPP using spontaneous parametric down conversion (SPDC) sources. By delicately designing the optical circuits, the double-pair emission noise caused by SPDC sources can be eliminated automatically. Combined with suitable quantum memory and entanglement swapping, this MB-EPP may have application potential in the implementation of a practical measurement-based quantum repeater.