Indranil Bayal¹, Pradipta Panchadhyayee^1,2,*

Journal of Quantum Computing, Vol.5, pp. 71-79, 2023, DOI:10.32604/jqc.2023.045164

Abstract The present model deals with a protocol which involves the generation and conversion of entanglement from path-spin (P-S) hybrid entanglement associated with half-spin particle to spin-spin (S-S) interparticle entanglement. This protocol finds its applications in quantum information processing via a series of operations which include a beam splitter, spin flipper, spin measurement, classical channel, unitary transformations. Finally, it leads to two particles having completely entangled spin variables, without any requirement of any simultaneous operation on the two particles. More >

Karoki A. Mũgambi^*, Geoffrey O. Okeng’o

Journal of Quantum Computing, Vol.5, pp. 25-40, 2023, DOI:10.32604/jqc.2023.045654

Abstract Quantum communication is a groundbreaking technology that is driving the future of information transmission and communication technologies to a new paradigm. It relies on quantum entanglement to facilitate the transmission of quantum states between parties. Quantum repeaters are crucial for facilitating long-distance quantum communication. These quantum devices act as intermediaries between adjacent communication channel segments within a fragmented quantum network, allowing for entanglement swapping between the channel segments. This entanglement swapping process establishes entanglement links between the endpoints of adjacent segments, gradually creating a continuous entanglement connection over the entire length of the transmission channel. The established quantum link can… More >

Dhananjay P. Mehendale^1,*, Madhav R. Modak²

Journal of Quantum Computing, Vol.5, pp. 15-24, 2023, DOI:10.32604/jqc.2023.043370

Abstract A multi-qubit pure quantum state is called separable when it can be factored as the tensor product of 1-qubit pure quantum states. Factorizing a general multi-qubit pure quantum state into the tensor product of its factors (pure states containing a smaller number of qubits) can be a challenging task, especially for highly entangled states. A new criterion based on the proportionality of the rows of certain associated matrices for the existence of certain factorization and a factorization algorithm that follows from this criterion for systematically extracting all the factors is developed in this paper. 3-qubit pure states play a crucial… More >

Pratik Roy^*, Saptarshi Sahoo, Amit Kumar Mandal, Indranil Basu

Journal of Quantum Computing, Vol.3, No.4, pp. 151-160, 2021, DOI:10.32604/jqc.2021.019864

Abstract Quantum Key Distribution seems very promising as it offers unconditional security, that’s why it is being implemented by the tech giants of the networking industry and government. Having quantum phenomenon as a backbone, QKD protocols become indecipherable. Here we have focused on the complexities of quantum key distribution and how this technology has contributed to secure key communication. This article gives an updated overview of this technology and can serve as a guide to get familiar with the current trends of quantum cryptography. More >

D. L. Khokhlov^*

Journal of Quantum Computing, Vol.2, No.3, pp. 147-150, 2020, DOI:10.32604/jqc.2020.014734

Abstract An interpretation of the entangled states is considered. Two-photon states of photon A on path a and photon B on path b with polarizations H, V are constructed. Two synchronized photons, 1 and 2, can take the paths a and b, with equal probability 50%. In the bases a, b and H, V, the states of the photons form the product states. In the basis 1, 2, the states of the photons form the entangled state. The states of the photons in the bases 1, 2; a, b; H, V are inseparable. The correlation of the photons due to the… More >

S. Abdel-Khalek^1,2,*, E. M. Khalil^1,3, Beida Alsubei¹, A. Al-Barakaty⁴, S. M. Abo Dahab⁵

CMC-Computers, Materials & Continua, Vol.66, No.3, pp. 2445-2456, 2021, DOI:10.32604/cmc.2021.013830

Abstract In this paper, we analyzed squeezing in the information entropy, quantum state fidelity, and qubit-qubit entanglement in a time-dependent system. The proposed model consists of two qubits that interact with a two-mode electromagnetic field under the dissipation effect. An analytical solution is calculated by considering the constants for the equations of motion. The effect of the general form of the time-dependent for qubit-field coupling and the dissipation term on the temporal behavior of the qubit-qubit entanglement, quantum state fidelity, entropy, and variance squeezing are examined. It is shown that the intervals of entanglement caused more squeezing for the case of… More >

Eman M. A. Hilal¹, E. M. Khalil^2,3,*, S. Abdel-Khalek^2,4

CMC-Computers, Materials & Continua, Vol.66, No.2, pp. 1227-1236, 2021, DOI:10.32604/cmc.2020.012659

Abstract The effect of the field–field interaction on a cavity containing two qubit (TQ) interacting with a two mode of electromagnetic field as parametric amplifier type is investigated. After performing an appropriate transformation, the constants of motion are calculated. Using the Schrödinger differential equation a system of differential equations was obtained, and the general solution was obtained in the case of exact resonance. Some statistical quantities were calculated and discussed in detail to describe the features of this system. The collapses and revivals phenomena have been discussed in details. The Shannon information entropy has been applied for measuring the degree of… More >

Yan Chang^{1, *}, Shibin Zhang¹, Lili Yan¹, Xueyang Li¹, Tian Cao¹, Qirun Wang²

CMC-Computers, Materials & Continua, Vol.65, No.1, pp. 879-896, 2020, DOI:10.32604/cmc.2020.010042

Abstract The secure key rate of quantum key distribution (QKD) is greatly reduced because of the untrusted devices. In this paper, to raise the secure key rate of QKD, a device-independent quantum key distribution (DIQKD) protocol is proposed based on hyper-entangled states and Bell inequalities. The security of the protocol is analyzed against the individual attack by an adversary only limited by the no-signaling condition. Based on the formalization of Clauser-Horne Shimony-Holt (CHSH) violation measurement on local correlation, the probability of a secure secret bit is obtained, which is produced by a pair of hyper-entangled particles. By analyzing the secure secret… More >

Tao Shang^{1, *}, Ran Liu¹, Jianwei Liu¹, Yafei Hou²

CMC-Computers, Materials & Continua, Vol.64, No.3, pp. 1629-1645, 2020, DOI:10.32604/cmc.2020.09820

Abstract Establishing entanglement is an essential task of quantum communication technology. Beyond entanglement, quantum discord, as a measure of quantum correlation, is a necessary prerequisite to the success of entanglement distribution. To realize efficient quantum communication based on quantum discord, in this paper, we consider the practical advantages of continuous variables and propose a feasible continuous-variable quantum network coding scheme based on quantum discord. By means of entanglement distribution by separable states, it can achieve quantum entanglement distribution from sources to targets in a butterfly network. Compared with the representative discrete-variable quantum network coding schemes, the proposed continuous-variable quantum network coding… More >

Tao Li¹, Qingsheng Yang^{1, *}, Lianhua Ma², Xiaojun Zhang^{2, *}

CMES-Computer Modeling in Engineering & Sciences, Vol.123, No.3, pp. 995-1014, 2020, DOI:10.32604/cmes.2020.09152

Abstract Phase transition of hydrogel, which is polymerized by polymer network, can be regarded as the transition of polymer network stability. The stability of the polymer network might be changed when the external environment changed. This change will lead to the transformation of sensitive hydrogels stability, thus phase transition of hydrogel take place. Here, we present a new free density energy function, which considers the non-gaussianity of the polymer network, chains entanglement and functionality of junctions through adding Gent hyplastic model and Edwards-Vilgis slip-link model to Flory-Huggins theory. A program to calculate the phase transition temperature was written based on new… More >