Journal articles: 'Quantum entanglement'

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BELAVKIN, VIACHESLAV P., and MASANORI OHYA. "QUANTUM ENTROPY AND INFORMATION IN DISCRETE ENTANGLED STATES." Infinite Dimensional Analysis, Quantum Probability and Related Topics 04, no. 02 (June 2001): 137–60. http://dx.doi.org/10.1142/s0219025701000425.

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Quantum entanglements, describing truly quantum couplings, are studied and classified for discrete compound states. We show that classical-quantum correspondences such as quantum encodings can be treated as d-entanglements leading to a special class of separable compound states. The mutual information for the d-compound and for q-compound (entangled) states leads to two different types of entropies for a given quantum state. The first one is the von Neumann entropy, which is achieved as the supremum of the information over all d-entanglements, and the second one is the dimensional entropy, which is achieved at the standard entanglement, the true quantum entanglement, coinciding with a d-entanglement only in the commutative case. The q-conditional entropy and q-capacity of a quantum noiseless channel, defined as the supremum over all entanglements, is given as the logarithm of the dimensionality of the input von Neumann algebra. It can double the classical capacity, achieved as the supremum over all semiquantum couplings (d-entanglements, or encodings), which is bounded by the logarithm of the dimensionality of a maximal Abelian subalgebra. The entropic measure for essential entanglement is introduced.

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Li, Ming-Cui, and Ai-Xi Chen. "Enhanced Entanglement in Hybrid Cavity Mediated by a Two-way Coupled Quantum Dot." Open Physics 18, no. 1 (February 28, 2020): 14–23. http://dx.doi.org/10.1515/phys-2020-0003.

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AbstractWe investigate theoretically the entanglement in a hybrid Fabry-Perot cavity system. A membrane in the cavity acts as a mechanical resonator, and a two-level quantum dot is coupled to both the cavity mode and the mechanical resonator. The entanglements between the cavity field and the mechanical resonator, between the mechanical resonator and the quantum dot, as well as between the cavity field and the quantum dot are observed. The logarithmic negativities in the first two subsystems are much larger than those in the system without two-way coupled quantum dot, and the entanglements are robust against the thermal temperature (entanglements still exist in tens of Kelvin). We also find that without direct coupling between the cavity field and the mechanical resonator, one can till observe effective entanglement between them in our system. Our work is helpful and may have potential applications in the research of multipartite entanglement in physical system.

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Belavkin, Viacheslav P. "On Entangled Information and Quantum Capacity." Open Systems & Information Dynamics 08, no. 01 (March 2001): 1–18. http://dx.doi.org/10.1023/a:1011328315055.

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The pure quantum entanglement is generalized to the case of mixed compound states to include the classical and quantum encodings as particular cases. The true quantum entanglements are characterized as transpose-CP but not CP maps. The entangled information is introduced as the relative entropy of the mutual and the input state and total information of the entangled states leads to two different types of entropy for a given quantum state: the von Neumann entropy, which is achieved as the supremum of the information over all c-entanglements, and the true quantum entropy, which is achieved at the standard entanglement. The q-capacity, defined as the supremum over all entanglements, doubles the c-capacity in the case of the simple algebra. The conditional q-entropy is positive, and q-information of a quantum channel is additive.

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Brezinski, Mark E. "The Advantages of Not Entangling Macroscopic Diamonds at Room Temperature." Journal of Atomic, Molecular, and Optical Physics 2012 (December 27, 2012): 1–9. http://dx.doi.org/10.1155/2012/469043.

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The recent paper entitled by K. C. Lee et al. (2011) establishes nonlocal macroscopic quantum correlations, which they term “entanglement”, under ambient conditions. Photon(s)-phonon entanglements are established within each interferometer arm. However, our analysis demonstrates, the phonon fields between arms become correlated as a result of single-photon wavepacket path indistinguishability, not true nonlocal entanglement. We also note that a coherence expansion (as opposed to decoherence) resulted from local entanglement which was not recognized. It occurred from nearly identical Raman scattering in each arm (importantly not meeting the Born and Markovian approximations). The ability to establish nonlocal macroscopic quantum correlations through path indistinguishability rather than entanglement offers the opportunity to greatly expand quantum macroscopic theory and application, even though it was not true nonlocal entanglement.

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LI, XI-HAN, XIAO-JIAO DUAN, FU-GUO DENG, and HONG-YU ZHOU. "ERROR-REJECTING BENNETT–BRASSARD–MERMIN QUANTUM KEY DISTRIBUTION PROTOCOL BASED ON LINEAR OPTICS OVER A COLLECTIVE-NOISE CHANNEL." International Journal of Quantum Information 08, no. 07 (October 2010): 1141–51. http://dx.doi.org/10.1142/s021974991000623x.

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Quantum entanglement is an important element of quantum information processing. Sharing entangled quantum states between two remote parties is a precondition of most quantum communication schemes. We will show that the protocol proposed by Yamamoto et al. (Phys. Rev. Lett.95 (2005) 040503) for transmitting single quantum qubit against collective noise with linear optics is also suitable for distributing the components of entanglements with some modifications. An additional qubit is introduced to reduce the effect of collective noise, and the receiver can take advantage of the time discrimination and the measurement results of the assistant qubit to reconstruct a pure entanglement with the sender. Although the scheme succeeds probabilistically, the fidelity of the entangled state is almost unity in principle. The resource used in our protocol to get a pure entangled state is finite, which establishes entanglement more easily in practice than quantum entanglement purification. Also, we discuss its application in quantum key distribution over a collective channel in detail.

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Poojary, Bhushan. "Dark Matter and Quantum Entanglement Decoded." International Journal of Applied Physics and Mathematics 4, no. 3 (2014): 180–83. http://dx.doi.org/10.7763/ijapm.2014.v4.279.

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Tao, Yunpeng. "Quantum entanglement: Principles and research progress in quantum information processing." Theoretical and Natural Science 30, no. 1 (January 15, 2024): 263–74. http://dx.doi.org/10.54254/2753-8818/30/20241130.

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Quantum entanglement is a peculiar phenomenon in quantum information science, characterized by nonclassical correlations between quantum states of subsystems in a quantum system. Since the proposal of the Einstein-Podolsky-Rosen (EPR) paradox by Einstein, Podolsky, and Rosen, quantum entanglement has sparked intense debates on local realism. Bells inequality experiment established the nonlocality of quantum mechanics. Currently, high-dimensional quantum entanglement of both deterministic and random states can be realized in systems such as photons and cold atoms. Technologies such as quantum teleportation, quantum teleportation, quantum computing, and others rely on quantum entanglement to achieve effects beyond classical limitations. Current research focuses on the implementation of macroscopic quantum entanglement and its significance in fundamental problems of quantum mechanics. Quantum entanglement opens up a new paradigm for information processing with broad application prospects. It is necessary to conduct in-depth research on the nature of quantum entanglement and its advantages in information processing. This paper reviews the theoretical foundations of quantum entanglement, methods of generation and detection, and research progress in its applications in the field of quantum information. It discusses the important applications of quantum entanglement in quantum communication, computing, and sensing and provides an outlook on the future development prospects of quantum entanglement technologies.

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Horodecki, Ryszard, Paweł Horodecki, Michał Horodecki, and Karol Horodecki. "Quantum entanglement." Reviews of Modern Physics 81, no. 2 (June 17, 2009): 865–942. http://dx.doi.org/10.1103/revmodphys.81.865.

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9

Vedral, Vlatko. "Quantum entanglement." Nature Physics 10, no. 4 (April 2014): 256–58. http://dx.doi.org/10.1038/nphys2904.

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MB. "Quantum entanglement." New Scientist 262, no. 3492 (May 2024): 41–42. http://dx.doi.org/10.1016/s0262-4079(24)00982-5.

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Chen, Xiao-Yu, Li-Zhen Jiang, and Zhu-An Xu. "Necessary and sufficient criterion for k-separability of N-qubit noisy GHZ states." International Journal of Quantum Information 16, no. 04 (June 2018): 1850037. http://dx.doi.org/10.1142/s0219749918500375.

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A Multipartite entangled state has many different kinds of entanglements specified by the number of partitions. The most essential example of multipartite entanglement is the entanglement of multi-qubit Greenberger–Horne–Zeilinger (GHZ) state in white noise. We explicitly construct the entanglement witnesses for these states with stabilizer generators of the GHZ states. For an [Formula: see text] qubit GHZ state in white noise, we demonstrate the necessary and sufficient criterion of separability when it is divided into [Formula: see text] parties with [Formula: see text] for arbitrary [Formula: see text] and [Formula: see text]. The criterion covers more than a half of all kinds of partial entanglements for [Formula: see text]-qubit GHZ states in white noise. For the rest of multipartite entanglement problems, we present a method to obtain the sufficient conditions of separability. As an application, we consider [Formula: see text] qubit GHZ state as a codeword of the degenerate quantum code passing through depolarizing channel. We find that the output state is neither genuinely entangled nor fully separable when the quantum channel capacity reduces from positive to zero.

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Kauffman, Louis H., and Samuel J. Lomonaco. "Quantum entanglement and topological entanglement." New Journal of Physics 4 (October 16, 2002): 73. http://dx.doi.org/10.1088/1367-2630/4/1/373.

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Che, Tianrui. "Demonstration and Comparison of Different Entanglement Fabrication Approaches." Highlights in Science, Engineering and Technology 38 (March 16, 2023): 487–92. http://dx.doi.org/10.54097/hset.v38i.5872.

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Quantum entanglement is the most representative feature of quantum mechanics to classical mechanics. It is the delocalization, non-classical strong correlation among multiple quantum system. It has been developed for nearly one hundred years and a lot of methods of production and applications have been proposed. Aiming at the generation mode of quantum entanglement, this study presents two general preparation methods of quantum entanglement sources, including spontaneous parametric down-conversion (SPDC) and the preparation of quantum entanglement sources based on the four-wave mixing (FWM) effect. The principle, advantages and disadvantages of quantum entanglement sources are analyzed respectively. Finally, the research and application direction of the preparation method of quantum entanglement source are prospected. With the ability of preparation of quantum entanglement source, the application of quantum entanglement developed quickly, (e.g., quantum teleportation, entanglement swapping, quantum key distribution and quantum dense coding in the area of communication), and other area such as quantum computer, quantum imaging, quantum ranging and quantum clock synchronization. These results shed light on guiding further exploration of entanglement fabrication.

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Kumar Avtar, Dr Ram. "Entanglement Dynamics in Quantum Networks: Towards Scalable Quantum Information Processing." Journal of Quantum Science and Technology 1, no. 1 (March 31, 2024): 30–34. http://dx.doi.org/10.36676/jqst.v1.i1.07.

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Entanglement dynamics plays a crucial role in the development of scalable quantum information processing architectures. Quantum networks, composed of interconnected quantum nodes, offer promising avenues for the distribution and manipulation of quantum information over long distances. In this paper, we investigate the dynamics of entanglement in quantum networks and explore strategies for achieving scalable quantum information processing. the generation, distribution, and preservation of entanglement in various network topologies and investigate the impact of noise and decoherence on entanglement dynamics. Furthermore, we discuss potential applications of entanglement in quantum communication, cryptography, and computation, highlighting the importance of understanding and controlling entanglement dynamics for realizing practical quantum technologies. Through theoretical analysis and numerical simulations, we provide insights into the challenges and opportunities associated with entanglement dynamics in quantum networks, paving the way towards scalable quantum information processing architectures.

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15

Gisin, Nicolas. "Entanglement 25 Years after Quantum Teleportation: Testing Joint Measurements in Quantum Networks." Entropy 21, no. 3 (March 26, 2019): 325. http://dx.doi.org/10.3390/e21030325.

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Twenty-five years after the invention of quantum teleportation, the concept of entanglement gained enormous popularity. This is especially nice to those who remember that entanglement was not even taught at universities until the 1990s. Today, entanglement is often presented as a resource, the resource of quantum information science and technology. However, entanglement is exploited twice in quantum teleportation. Firstly, entanglement is the “quantum teleportation channel”, i.e., entanglement between distant systems. Second, entanglement appears in the eigenvectors of the joint measurement that Alice, the sender, has to perform jointly on the quantum state to be teleported and her half of the “quantum teleportation channel”, i.e., entanglement enabling entirely new kinds of quantum measurements. I emphasize how poorly this second kind of entanglement is understood. In particular, I use quantum networks in which each party connected to several nodes performs a joint measurement to illustrate that the quantumness of such joint measurements remains elusive, escaping today’s available tools to detect and quantify it.

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Tang, Jiangmei, Shaomeng Wang, Bingyang Liang, and Yubin Gong. "Research on Intraparticle to Interparticle Entanglement Swapping Protocols." Applied Sciences 14, no. 17 (September 8, 2024): 8035. http://dx.doi.org/10.3390/app14178035.

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Entanglement is one of the most striking features of quantum systems, whereby its non-classical correlation is an essential resource in numerous quantum protocols. Entanglement can be divided into two categories: interparticle and intraparticle entanglement. There are both distinctions and similarities between these two kinds of entangled states. This work delves into these distinctions and similarities from the following aspects: correlation and non-locality, robustness, the mechanisms of generation and separation, and practical applications. Entanglement swapping is a technique based on quantum entanglement. As entanglement has different categories, entanglement swapping also has various types, including interparticle to interparticle and intraparticle to interparticle. Swapping protocols from intraparticle entanglement to interparticle entanglement can be applied to super quantum dense encoding, quantum information transmission, quantum teleportation, etc. Thus, this work proposes three swapping protocols, from spin–orbit intraparticle entanglement to spin–spin interparticle entanglement, based on Bell state joint measurement, the cross-Kerr medium, and linear optical elements. This work can help us better understand entanglement by analyzing the differences and similarities between the two types of entangled states. It can also enhance entanglement swapping protocols, from spin–orbit intraparticle to spin–spin interparticle entanglement, for use in quantum information transfer.

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Semenenko, Vyacheslav, Xuedong Hu, Eden Figueroa, and Vasili Perebeinos. "Entanglement generation in a quantum network with finite quantum memory lifetime." AVS Quantum Science 4, no. 1 (March 2022): 012002. http://dx.doi.org/10.1116/5.0082239.

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We simulate entanglement sharing between two end-nodes of a linear chain quantum network using SeQUeNCe, an open-source simulation package for quantum networks. Our focus is on the rate of entanglement generation between the end-nodes with many repeaters with a finite quantum memory lifetime. Numerical and analytical simulations show limits of connection performance for a given number of repeaters involved, memory lifetimes, the distance between the end-nodes, and an entanglement management protocol. Our findings demonstrate that the performance of quantum connection depends highly on the entanglement management protocol, which schedules entanglement generation and swapping, resulting in the final end-to-end entanglement.

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Horodecki, Karol, Michal Horodecki, and Pawel Horodecki. "Are quantum correlations symmetric?" Quantum Information and Computation 10, no. 11&12 (November 2010): 901–10. http://dx.doi.org/10.26421/qic10.11-12-1.

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We provide operational definition of asymmetry of entanglement: An entangled state contains asymmetric entanglement if its subsystems can not be exchanged (swapped) by means of local operations and classical communication. We show that in general states have asymmetric entanglement. This allows to construct nonsymmetric measure of entanglement, and a parameter that reports asymmetry of entanglement contents of quantum state. We propose asymptotic measure of asymmetry of entanglement, and show that states for which it is nonzero, contain necessarily bound entanglement.

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Amirul Asyraf Zhahir, Siti Munirah Mohd, Mohd Ilias M Shuhud, Bahari Idrus, Hishamuddin Zainuddin, Nurhidaya Mohamad Jan, and Mohamed Ridza Wahiddin. "Entanglement Detection: A Scoping Review." Journal of Advanced Research in Applied Sciences and Engineering Technology 42, no. 2 (April 3, 2024): 209–20. http://dx.doi.org/10.37934/araset.42.2.209220.

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Quantum entanglement is a critical physical process in quantum mechanics and quantum information theory. It is a required process in quantum computing, quantum teleportation, and quantum cryptography. Entanglement detection affects the performance of quantum information processing tasks. Entanglement detection has grown in popularity over the years, and various entanglement detection methods are available, though some have application and system scale limitations. This scoping review sought to identify various measurement methods for entanglement detection in both bipartite and multipartite entanglement systems. Secondary resource indexed literatures were selected based on specific keywords from literatures published between 2017 and 2021. The goal of this study is to present a proposed conceptual framework of entanglement detection based on previous work as a guidance and reference founded on one’s specific requirements.

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WEN, JIAYAN, and DAOWEN QIU. "ENTANGLEMENT IN ADIABATIC QUANTUM SEARCHING ALGORITHMS." International Journal of Quantum Information 06, no. 05 (October 2008): 997–1009. http://dx.doi.org/10.1142/s0219749908004249.

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Quantum entanglement is widely considered as one of the key resources for quantum-computational power. However, present interpretations of entanglement in speeding up of quantum algorithms remain far from complete. We analyze and compare the behaviors of entanglement during the adiabatic evolution of Grover's quantum search algorithms with complexity [Formula: see text] and O(1), respectively. Our results show that entanglement has a significant impact on the computational efficiency of both algorithms. That is, the greater the entanglement, the higher is the quantum computation, and vice versa. Furthermore, the correlations between entanglement and energy are discussed. It is observed that for the algorithm with complexity O(1), its entanglement degree becomes larger when the energy input into the quantum system increases, thus making the algorithm more efficient.

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Isar, Aurelian. "Quantum Entanglement and Quantum Discord of Two-Mode Gaussian States in a Thermal Environment." Open Systems & Information Dynamics 18, no. 02 (June 2011): 175–90. http://dx.doi.org/10.1142/s1230161211000121.

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In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we give a description of the continuous-variable quantum entanglement and quantum discord for a system consisting of two noninteracting modes embedded in a thermal environment. Entanglement and discord are used to quantify the quantum correlations of the system. For all values of the temperature of the thermal reservoir, an initially separable Gaussian state remains separable for all times. We study the time evolution of logarithmic negativity, which characterizes the degree of entanglement, and we show that in the case of an entangled initial Gaussian state, entanglement suppression (entanglement sudden death) takes place for non-zero temperatures of the environment. Only for zero temperature of the thermal bath the initial entangled state remains entangled for finite times. We analyze time evolution of Gaussian quantum discord, which is a measure of all quantum correlations in the bipartite state, including entanglement, and we show that quantum discord decays asymptotically in time under the effect of thermal bath. This is in contrast with the sudden death of entanglement. Before the suppression of entanglement, the qualitative evolution of quantum discord is very similar to that of the entanglement. We describe also time evolution of the degree of classical correlations and of quantum mutual information, which measures the total correlations of quantum system.

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Wang, Yifan. "State-of-art applications and the function of quantum entanglement in quantum information." Theoretical and Natural Science 10, no. 1 (November 17, 2023): 9–15. http://dx.doi.org/10.54254/2753-8818/10/20230302.

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Quantum information is a cutting-edge technology that has numerous applications. It mainly makes usage of some quantum entanglement characteristics and uses the quantum entangled state as a carrier for information transfer. Therefore, compared to traditional information, quantum information has excellent features, e.g., stronger security and reduced susceptibility to interference. This article introduces the definition, concept, characteristics and history of quantum entanglement and quantum information. To be specific, this study lists the applications of quantum entanglement in communication and radar. In addition, it gives an outlook on the future function of quantum entanglement in quantum information based on the advantages and disadvantages of quantum entanglement. Contemporarily, the field of physics is rapidly advancing in both quantum entanglement and quantum information, and there have also been significant technological advancements. In experiments, scientists have been able to extend the transmission distance of quantum information to great distances. At the same time, scholars are looking for ways to minimise the interference of quantum information during transmission. In constant exploration and experimentation, the experimental results have inspired scientists to explore the deeper realms of quantum information.

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Moran, Stacey. "Quantum Decoherence." Philosophy Today 63, no. 4 (2019): 1051–68. http://dx.doi.org/10.5840/philtoday20191220295.

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The central argument in this essay is that while the concept of entanglement offers materialism the promise of a conceptually rich field of new “entangled” entities, by itself, entanglement is ill-equipped to contend with the thorny questions of how power is organized among those entities. This essay proposes that decoherence provides a welcome complement to entanglement.

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PARK, DAEKIL. "ENTANGLEMENT DEGRADATION IN THE PRESENCE OF (4 + n)-DIMENSIONAL SCHWARZSCHILD BLACK HOLE." International Journal of Quantum Information 11, no. 01 (February 2013): 1350014. http://dx.doi.org/10.1142/s0219749913500147.

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In this paper, we compute the various bipartite quantum correlations in the presence of the (4 + n)-dimensional Schwarzschild black hole. In particular, we focus on the n-dependence of various bosonic bipartite entanglements. For the case between Alice and Rob, where the former is free falling observer and the latter is at the near-horizon region, the quantum correlation is degraded compared to the case in the absence of the black hole. The degradation rate increases with decreasing n. We also compute the physically inaccessible correlations. It is found that there is no creation of quantum correlation between Alice and AntiRob. For the case between Rob and AntiRob the quantum entanglement is created although they are separated in the causally disconnected regions. It is found that contrary to the physically accessible correlation the entanglement between Rob and AntiRob decreases with increasing n.

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Zangi, Sultan M., Chitra Shukla, Atta ur Rahman, and Bo Zheng. "Entanglement Swapping and Swapped Entanglement." Entropy 25, no. 3 (February 25, 2023): 415. http://dx.doi.org/10.3390/e25030415.

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Entanglement swapping is gaining widespread attention due to its application in entanglement distribution among different parts of quantum appliances. We investigate the entanglement swapping for pure and noisy systems, and argue different entanglement quantifiers for quantum states. We explore the relationship between the entanglement of initial states and the average entanglement of final states in terms of concurrence and negativity. We find that if initial quantum states are maximally entangled and we make measurements in the Bell basis, then average concurrence and average negativity of final states give similar results. In this case, we simply obtain the average concurrence (average negativity) of the final states by taking the product of concurrences (negativities) of the initial states. However, the measurement in non-maximally entangled basis during entanglement swapping degrades the average swapped entanglement. Further, the product of the entanglement of the initial mixed states provides an upper bound to the average swapped entanglement of final states obtained after entanglement swapping. The negativity work well for weak entangled noisy states but concurrence gives better results for relatively strong entanglement regimes. We also discuss how successfully the output state can be used as a channel for the teleportation of an unknown qubit.

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Liang, Bin. "The Nature and Realization of Quantum Entanglement." Applied Physics Research 8, no. 6 (November 30, 2016): 96. http://dx.doi.org/10.5539/apr.v8n6p96.

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<p class="1Body">This paper analyses the nature of quantum entanglement, proves the quantum entanglement is not action at a distance, proposes a scheme to realize quantum entanglement, explains that the quantum entanglement is not action at a distance and the non-cloning theorem of quantum state ensure the quantum mechanics is consistent with relativity and make the superluminal communication could not happened.</p>

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Pezzè, Luca, Yan Li, Weidong Li, and Augusto Smerzi. "Witnessing entanglement without entanglement witness operators." Proceedings of the National Academy of Sciences 113, no. 41 (September 28, 2016): 11459–64. http://dx.doi.org/10.1073/pnas.1603346113.

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Quantum mechanics predicts the existence of correlations between composite systems that, although puzzling to our physical intuition, enable technologies not accessible in a classical world. Notwithstanding, there is still no efficient general method to theoretically quantify and experimentally detect entanglement of many qubits. Here we propose to detect entanglement by measuring the statistical response of a quantum system to an arbitrary nonlocal parametric evolution. We witness entanglement without relying on the tomographic reconstruction of the quantum state, or the realization of witness operators. The protocol requires two collective settings for any number of parties and is robust against noise and decoherence occurring after the implementation of the parametric transformation. To illustrate its user friendliness we demonstrate multipartite entanglement in different experiments with ions and photons by analyzing published data on fidelity visibilities and variances of collective observables.

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Ahn, C., H. M. Wiseman, and G. J. Milburn. "Quantum Control and Quantum Entanglement." European Journal of Control 9, no. 2-3 (January 2003): 279–84. http://dx.doi.org/10.3166/ejc.9.279-284.

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Shih, Y. H. "Quantum entanglement and quantum teleportation." Annalen der Physik 513, no. 1-2 (February 2001): 19–34. http://dx.doi.org/10.1002/andp.200151301-202.

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DATTA, ANIMESH, and ANIL SHAJI. "QUANTUM METROLOGY WITHOUT QUANTUM ENTANGLEMENT." Modern Physics Letters B 26, no. 18 (June 17, 2012): 1230010. http://dx.doi.org/10.1142/s0217984912300104.

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We scrutinize the role of quantum entanglement in quantum metrology and discuss recent advances in nonlinear quantum metrology that allow improved scalings of the measurement precision with respect to the available resources. Such schemes can surpass the conventional Heisenberg limited scaling of 1/N of quantum enhanced metrology. Without investing in the preparation of entangled states, we review how systems with intrinsic nonlinearities such as Bose–Einstein condensates and light-matter interfaces can provide improved scaling in single parameter estimation.

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Hollberg, Leo, Luigi Lugiato, Anatoly Oraevski, Alexander Sergienko, and Victor Zadkov. "Quantum optics and quantum entanglement." Journal of Optics B: Quantum and Semiclassical Optics 5, no. 4 (August 1, 2003): 457. http://dx.doi.org/10.1088/1464-4266/5/4/001.

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Shih, Y. H. "Quantum entanglement and quantum teleportation." Annalen der Physik 10, no. 1-2 (February 2001): 19–34. http://dx.doi.org/10.1002/1521-3889(200102)10:1/2<19::aid-andp19>3.0.co;2-f.

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Ye, MingYong, YongSheng Zhang, and GuangCan Guo. "Quantum entanglement and quantum operation." Science in China Series G: Physics, Mechanics and Astronomy 51, no. 1 (January 2008): 14–21. http://dx.doi.org/10.1007/s11433-008-0013-x.

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Zeng, Yiming, Jiarui Zhang, Zhenhua Liu, and Yuanyuan Yang. "Entanglement Management through Swapping over Quantum Internets." ACM SIGMETRICS Performance Evaluation Review 51, no. 2 (September 28, 2023): 69–71. http://dx.doi.org/10.1145/3626570.3626595.

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Quantum Internet has the potential to support a wide range of applications in quantum communication and quantum computing by generating, distributing, and processing quantum information. Generating a long-distance quantum entanglement is one of the most essential functions of a quantum Internet to facilitate these applications. However, entanglement is a probabilistic process, and its success rate drops significantly as distance increases. Entanglement swapping is an efficient technique used to address this challenge. How to efficiently manage the entanglement through swapping is a fundamental yet challenging problem. In this paper, we will consider two swapping methods: (1) BSM: a classic entanglement-swapping method based on Bell State measurements that fuse two successful quantum links, (2) nfusion: a more general and efficient swapping method based on Greenberger-Horne-Zeilinger measurements, capable of fusing n successful quantum links. Our goal is to maximize the entanglement rate for multiple quantum-user pairs over the quantum Internet with an arbitrary topology. We propose efficient entanglement management algorithms that utilized the unique properties of BSM and n-fusion. Evaluation results highlight that our approach outperforms existing routing protocols.

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JUNG, EYLEE, MI-RA HWANG, and DAEKIL PARK. "QUANTUM DISCORD AND QUANTUM ENTANGLEMENT IN THE PRESENCE OF AN ASYMPTOTICALLY FLAT STATIC BLACK HOLE." International Journal of Quantum Information 11, no. 06 (September 2013): 1350061. http://dx.doi.org/10.1142/s0219749913500615.

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In this work, the quantum discord and tripartite entanglement in the presence of an asymptotically flat static black hole are discussed. The total correlation, quantum discord, and classical correlation are found to exhibit decreasing behavior with increasing Hawking temperature. It is shown that the classical correlation is less than the quantum discord in the full range of Hawking temperature. The tripartite entanglements for Greenberger–Horne–Zeilinger (GHZ) and W-states also exhibit decreasing behavior with increasing Hawking temperature. When the Hawking temperature approaches the infinite limit, the tripartite entanglements of the GHZ and W-states reduce, in terms of the π-tangle, to 52% and 33% of the corresponding values in the flat space limit, respectively.

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Wang, Hailong, Yajuan Zhang, Xiong Zhang, Jun Chen, Huaping Gong, and Chunliu Zhao. "The Effect of Quantum Noise on Multipartite Entanglement from a Cascaded Parametric Amplifier." Photonics 10, no. 3 (March 13, 2023): 307. http://dx.doi.org/10.3390/photonics10030307.

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The tripartite entanglement generated from a cascaded parametric amplifier is always present in the whole gain region in the ideal condition. However, in practical applications, the quantum entanglement is very fragile and easily deteriorated by quantum noise from interactions with external environments, e.g., the avoidable attenuation and amplification operations may lead to some degradation effects on the quantum entanglement. Therefore, in this work, bipartite entanglement for the three pairs and tripartite entanglement in this cascaded parametric amplifier under the circumstances of attenuation and amplification operations are analyzed by using positivity under partial transposition criterion. The results show that tripartite entanglement is robust to the deterioration effects from the attenuation and amplification operations rather than bipartite entanglement. Our results may find some practical applications of multipartite quantum entanglement in quantum secure communications.

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Amirul Asyraf Zhahir, Siti Munirah Mohd, Mohd Sham Mohamad, Mohd Ilias M Shuhud, Bahari Idrus, Hishamuddin Zainuddin, and Nurhidaya Mohamad Jan. "Quantum Entanglement and Its Classification Protocols." Malaysian Journal of Science Health & Technology 10, no. 2 (October 8, 2024): 99–106. http://dx.doi.org/10.33102/mjosht.v10i2.408.

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Quantum entanglement has its own major role in quantum information theory. Its application in numerous areas namely quantum computing, quantum cryptography and quantum teleportation are proven vital and essential. Over the last decades, the interests in quantum entanglement have grown and significant progress in quantum computing has been revealed. However, the classification of entanglement was proved to be challenging especially in a higher qubit-dimensional system setting. In this review, indexed literature as the secondary resource was chosen by specific keywords from several database. In reference to the literatures review, there exists several entanglement classifications protocols that will be presented in this paper namely local unitary (LU), local operations and classical communication (LOCC), and stochastic local operations and classical communication (SLOCC). This study will offer a better understanding of quantum entanglement and the entanglement classification protocols.

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38

Sørensen, Erik S., Ming-Shyang Chang, Nicolas Laflorencie, and Ian Affleck. "Quantum impurity entanglement." Journal of Statistical Mechanics: Theory and Experiment 2007, no. 08 (August 1, 2007): P08003. http://dx.doi.org/10.1088/1742-5468/2007/08/p08003.

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Siomau, Michael. "Quantum entanglement percolation." Journal of Physics B: Atomic, Molecular and Optical Physics 49, no. 17 (August 19, 2016): 175506. http://dx.doi.org/10.1088/0953-4075/49/17/175506.

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Sumairi, AiniSyahida, S. N. Hazmin, and C. H. Raymond Ooi. "Quantum entanglement criteria." Journal of Modern Optics 60, no. 7 (April 2013): 589–97. http://dx.doi.org/10.1080/09500340.2013.796016.

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Terhal, Barbara M. "Detecting quantum entanglement." Theoretical Computer Science 287, no. 1 (September 2002): 313–35. http://dx.doi.org/10.1016/s0304-3975(02)00139-1.

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Dima, A., and M. Dima. "Quantum Entanglement Oscillations." International Journal of Theoretical Physics 48, no. 11 (September 11, 2009): 3228–33. http://dx.doi.org/10.1007/s10773-009-0124-9.

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Martín-Martínez, Eduardo, and Nicolas C. Menicucci. "Cosmological quantum entanglement." Classical and Quantum Gravity 29, no. 22 (October 18, 2012): 224003. http://dx.doi.org/10.1088/0264-9381/29/22/224003.

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Dugić, M. "Quantum entanglement suppression." Europhysics Letters (EPL) 60, no. 1 (October 2002): 7–13. http://dx.doi.org/10.1209/epl/i2002-00310-1.

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Brooks, Michael. "4. Quantum entanglement." New Scientist 230, no. 3071 (April 2016): 31–32. http://dx.doi.org/10.1016/s0262-4079(16)30765-5.

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Ki, Dae-Han, and Young-Dae Jung. "Quantum Screening Effects on the Entanglement Fidelity for Elastic Collisions in Electron-Ion Quantum Plasmas." Zeitschrift für Naturforschung A 65, no. 12 (December 1, 2010): 1143–46. http://dx.doi.org/10.1515/zna-2010-1220.

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The quantum screening effects on the entanglement fidelity for the elastic collision are investigated in electron-ion quantum plasmas. The partial wave analysis and modified Debye-Hückel interaction potential are employed to obtain the entanglement fidelity function in electron-ion quantum plasmas as a function of the collision energy, charge of the ion, and quantum wave number. It is found that the quantum screening effects significantly enhance the entanglement fidelity in electron-ion quantum plasmas. It is also found that the entanglement fidelity increases with an increase of the ion charge. The quantum screening effects on the entanglement fidelity is also found to be increased with increasing plasma density. In addition, it is found that the quantum screening effects decreases with an increase of the collision energy.

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Wang, Hailong, Ning Ru, and Pingwei Lin. "Generation of Three-Mode Entanglement Based on Parametric Amplifiers Using Quantum Entanglement Swapping." Photonics 9, no. 10 (September 23, 2022): 687. http://dx.doi.org/10.3390/photonics9100687.

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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.

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Makarov, Dmitry, and Yuliana Tsykareva. "Quantum Entanglement of Monochromatic and Non-Monochromatic Photons on a Waveguide Beam Splitter." Entropy 24, no. 1 (December 27, 2021): 49. http://dx.doi.org/10.3390/e24010049.

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It is well known that the waveguide beam splitter can be used as a source for the quantum entanglement of photons. The analysis of such quantum entanglement is a difficult problem even for monochromatic photons, since the system under study is multiparametric. This paper will show that quantum entanglement can be represented in a simple form not only for monochromatic photons but also for non-monochromatic ones. It will be shown that quantum entanglement for non-monochromatic photons can be very different from monochromatic photons, which can be used to create large quantum entanglement.

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True, Sarah, and Alioscia Hamma. "Transitions in Entanglement Complexity in Random Circuits." Quantum 6 (September 22, 2022): 818. http://dx.doi.org/10.22331/q-2022-09-22-818.

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Entanglement is the defining characteristic of quantum mechanics. Bipartite entanglement is characterized by the von Neumann entropy. Entanglement is not just described by a number, however; it is also characterized by its level of complexity. The complexity of entanglement is at the root of the onset of quantum chaos, universal distribution of entanglement spectrum statistics, hardness of a disentangling algorithm and of the quantum machine learning of an unknown random circuit, and universal temporal entanglement fluctuations. In this paper, we numerically show how a crossover from a simple pattern of entanglement to a universal, complex pattern can be driven by doping a random Clifford circuit with T gates. This work shows that quantum complexity and complex entanglement stem from the conjunction of entanglement and non-stabilizer resources, also known as magic.

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Li, Ming, Shao-Ming Fei, and Xianqing Li-Jost. "Quantum Entanglement: Separability, Measure, Fidelity of Teleportation, and Distillation." Advances in Mathematical Physics 2010 (2010): 1–57. http://dx.doi.org/10.1155/2010/301072.

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Quantum entanglement plays crucial roles in quantum information processing. Quantum entangled states have become the key ingredient in the rapidly expanding field of quantum information science. Although the nonclassical nature of entanglement has been recognized for many years, considerable efforts have been taken to understand and characterize its properties recently. In this review, we introduce some recent results in the theory of quantum entanglement. In particular separability criteria based on the Bloch representation, covariance matrix, normal form and entanglement witness, lower bounds, subadditivity property of concurrence and tangle, fully entangled fraction related to the optimal fidelity of quantum teleportation, and entanglement distillation will be discussed in detail.

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Journal articles on the topic 'Quantum entanglement'

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