Degree Of Entanglement Research Articles

The influence of entanglement degree controlled by complex shear field on the performance of long-chain branched polypropylene

The influence of entanglement degree controlled by complex shear field on the performance of long-chain branched polypropylene

Quantum Cournot model based on general entanglement operator

The properties of the Cournot model based on the most general entanglement operator containing quadratic expressions which is symmetric with respect to the exchange of players are considered. The degree of entanglement of games dependent on one and two squeezing parameters and their payoff values in Nash equilibrium are compared. The analysis showed that the relationship between the degree of entanglement of the initial state of the game and the payoff values in Nash equilibrium is ambiguous. The phase values included in the entanglement operator have a strong influence on the final outcome of the game. In a quantum duopoly based on the initial state of a game that depends on one squeezing parameter, the maximum possible payoff in Nash equilibrium cannot be reached when the value of the phase parameter is greater than zero, in contrast with a game that depends on two parameters.

Enhancing the Stereocomplex Crystallization of PLLA/PDLA Symmetric Blend by Controlling the Degree of Molecular Chain Entanglement

In order to enhance the content of stereocomplex crystals (SC) in poly L-lactic acid (PLLA)/poly D-lactic acid (PDLA) symmetric blend, thereby improving the defects of low crystallinity and poor heat resistance of polylactic acid (PLA)-based materials, the samples with different entanglement degrees were prepared by freezing extration method. The critical overlap concentration of the blend system was quantitatively obtained using an Ubbelohde viscometer. Based on this concentration, samples with a series of concentration gradient were prepared to control the different degrees of molecular chain entanglement inside. The results indicated that the chain disentanglement could greatly increase the content of SC in the blend, whether in the precipitation crystallization or the melt crystallization process. Especially after the isothermal crystallization for 30min at 130oC, the L/D-0.1 sample with the highest degree of disentanglement almost only formed SC, accounting for 95.2% of the total crystallinity. Samples with lower entanglement degree had more crystal nuclei and faster growth rate of formed spherulites. For completely entangled sample L/D-50, the crystal nucleus of homo-crystalls (HC) could be considered as SC. Besides, the Vicat softening temperature (VST) of L/D-0.1 sample increased from 79.9oC of L/D-50 sample to 103.8oC with an obvious increase of 24.9oC. All these results provide new ideas for improving the performance of PLA-based materials and show promising development prospects of green and sustainable polymers.

Enhancement of opto-electro-mechanical entanglement through three-level atoms

We address the dynamical bipartite entanglement in an opto-electro-mechanical system that involves a three-level atom. The system consists of a degenerate three-level atom, a mechanical resonator, an optical cavity, and a microwave cavity. By utilizing the linearization approximation and nonlinear quantum-Langevin equations, the dynamics of the system are analyzed, and the bipartite entanglement is evaluated using the logarithmic negativity. The research findings indicate that the entanglement between each subsystem increases with the atom injection rate, suggesting that a higher atom injection rate leads to enhanced information transmission between the subsystems. Additionally, it is observed that the correlation between subsystems increases with an increase in the coupling rate. Moreover, the study demonstrates that the correlation between each subsystem decreases as temperature rises. We also show that the degree of tripartite entanglement diminishes with increasing atomic decay rates. The results highlight the positive impact of three-level atoms on the bipartite entanglement in an opto-electro-mechanical system. Consequently, such electro-optomechanical systems can offer a framework for optomechanical information transfer.

Research on the Correlation between Quantum Entanglement and Thinking Consciousness

The development of quantum technology has profoundly influenced research on consciousness. By analyzing the interaction of various microscopic particles in the universe, the article proposed that all things exhibit interconnected non-locality in both time and space, and that the interrelated connections of everything in the universe are based on quantum entanglement. Through analysis of the cellular and nervous system functions of organisms, as well as the influence of quantum science theories on consciousness and combined with research results in related fields, this paper presents the following viewpoints: first, life bodies exhibit quantum entanglement phenomena. Second, biological electricity phenomena are closely tied to consciousness. Third, both life bodies and non-life bodies are conscious, but different entities exhibit varying degrees of strong and weak consciousness. The strong and weak thinking consciousness influences the fluctuation of quantum and the size of quantum entanglement degree. Quantum fluctuations affect the consciousness of both life bodies and non-life bodies, and the entanglement quantum influences the degree of inductance between each other. Finally, the combination of quantum entanglement technology and thinking consciousness can realize the interconnection between human beings and the universe. Consciousness may affect the results measured in quantum mechanics when people observe. However, the macroscopic world mainly adopts the laws of classical physics to solve problems in life. Under certain conditions, the law of quantum physics and the law of classical physics can affect people’s lives together. No matter what angle we view the material world, it is real, and the universe is not illusory.

Regression of Concurrence via Local Unitary Invariants

Concurrence is a crucial entanglement measure in quantum theory used to describe the degree of entanglement between two or more qubits. Local unitary (LU) invariants can be employed to describe the relevant properties of quantum states. Compared to quantum state tomography, observing LU invariants can save substantial physical resources and reduce errors associated with tomography. In this paper, we use LU invariants as explanatory variables and employ methods such as multiple regression, tree models, and BP neural network models to fit the concurrence of 2-qubit quantum states. For pure states and Werner states, by analyzing the correlation between data, a functional formula for concurrence in terms of LU invariants is obtained. Additionally, for any two-qubit quantum states, the prediction accuracy for concurrence reaches 98.5%.

Dynamical evolution of a five-level atom interacting with an intensity-dependent coupling regime influenced by a nonlinear Kerr-like medium

We present an analytical solution for a quantum system characterized by a double Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda$$\\end{document} five-level atom interacting with an intensity-dependent coupling regime, influenced by a nonlinear Kerr-like medium. We also derive the constants of motion through Heisenberg’s equations. Furthermore, the dynamical evolution of the entanglement and quantum coherence between the atom and the field is discussed using linear entropy and l1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$l_{1}$$\\end{document}-norm of coherence. Through a comprehensive examination of the quantum system, it is observed that both the detuning and the Kerr-like parameters exert a significant impact on the degree of entanglement and coherence. However, the impacts of detuning and the Kerr effect become less pronounced when the photon multiplicity is high. In addition, we conduct a comparison between the five-level atomic system and a four-level system, revealing that the number of energy levels has a profound impact on the behavior of entanglement and coherence. These findings highlight the importance of atomic structure and photon multiplicity in controlling and optimizing quantum processes, particularly in applications involving quantum communication and information processing.

Quantum Entanglement in Nonlinear Coupler with Raman Process

This paper examines the possible quantum entanglement generated in a coupler system consisting of two waveguides, where one waveguide is nonlinear and Raman-active, while the other waveguide only undergoes linear processes. The analytical-perturbative method is employed to investigate the production of entangled states in the given system. The Hillery-Zubairy criterion is employed to examine the possible quantum entanglement between the two fundamental pump modes propagating in both waveguides. We explore the generation of quantum entanglement under different initial conditions and critical design parameters. The simulation results suggest a continuous entanglement that remains until a particular distance of interaction is reached. As the linear coupling parameter increases, the relationship between the maximum reachable distance for entanglement and the degree of entanglement becomes more complex. The study reveals that entanglement experiences significant fluctuations when there is a substantial frequency mismatch between the modes.

Protocol for certifying entanglement in surface spin systems using a scanning tunneling microscope

Certifying quantum entanglement is a critical step toward realizing quantum-coherent applications. In this work, we show that entanglement of spins can be unambiguously evidenced in a scanning tunneling microscope with electron spin resonance by exploiting the fact that entangled states undergo a free time evolution with a distinct characteristic time constant that clearly distinguishes it from the time evolution of non-entangled states. By implementing a phase control scheme, the phase of this time evolution can be mapped back onto the population of one entangled spin, which can then be read out reliably using a weakly coupled sensor spin in the junction of the scanning tunneling microscope. We demonstrate through open quantum system simulations with currently available spin coherence times of T2 ≈ 300 ns, that a signal directly correlated with the degree of entanglement can be measured at temperatures of 100–400 mK accessible in sub-Kelvin scanning tunneling microscopes.

Influence of Metal Ions on the Structural Complexity of Mixed-Ligand Divalent Coordination Polymers

The reactions of the angular ligand 4,4′-oxybis(N-(pyridin-3-yl)benzamide) (L1) and 1,4-naphthalenedicarboxylic acid (1,4-H2NDC) with divalent metal salts yielded three distinct coordination polymers (CPs): {[Zn2(L1)(1,4-NDC)2]·MeOH}n, 1, {[Cu(L1)(1,4-NDC)(H2O)]·3H2O}n, 2, and {[Cd(L1)(1,4-NDC)]·2H2O}n, 3. Complex 1 features a 2-fold interpenetrated 3D framework with the (412·63)-pcu topology, while complex 2 reveals a 1D triple-strained helical chain and complex 3 displays a 3-fold interpenetrated 3D framework with (66)-dia topology. Additionally, the reactions of the flexible ligand N,N′-bis(3-methylpyridyl) adipoamide (L2) afforded {[Co4(L2)0.5(1,4-NDC)3(H2O)3(µ3-OH)2]·EtOH·2H2O}n, 4, {[Zn2(L2)(1,4-NDC)2]·2CH3OH}n, 5, and [Cd(L2)(adipic)(H2O)]n (H2adipic = adipic acid), 6, exhibiting a self-catenated 3D framework with the (420·68)-8T32 topology, a 2D layer with the (413·62) − (4,4)IIb topology, and a 2D layer with the (44·62)-sql topology, respectively. The structural diversity observed in complexes 1–6 highlights the pivotal influence of the metal center on the degree of entanglement in CPs within mixed-ligand systems. The thermal stability and luminescent properties of complexes 1–3, 4, and 6 are also discussed.

Improving Quantum Optimization Algorithms by Constraint Relaxation

Quantum optimization is a significant area of quantum computing research with anticipated near-term quantum advantages. Current quantum optimization algorithms, most of which are hybrid variational-Hamiltonian-based algorithms, struggle to present quantum devices due to noise and decoherence. Existing techniques attempt to mitigate these issues through employing different Hamiltonian encodings or Hamiltonian clause pruning, but they often rely on optimistic assumptions rather than a deep analysis of the problem structure. We demonstrate how to formulate the problem Hamiltonian for a quantum approximate optimization algorithm that satisfies all the requirements to correctly describe the considered tactical aircraft deconfliction problem, achieving higher probabilities for finding solutions compared to previous works. Our results indicate that constructing Hamiltonians from an unconventional, quantum-specific perspective with a high degree of entanglement results in a linear instead of exponential number of entanglement gates instead and superior performance compared to standard formulations. Specifically, we achieve a higher probability of finding feasible solutions: finding solutions in nine out of nine instances compared to standard Hamiltonian formulations and quadratic programming formulations known from quantum annealers, which only found solutions in seven out of nine instances. These findings suggest that there is substantial potential for further research in quantum Hamiltonian design and that gate-based approaches may offer superior optimization performance over quantum annealers in the future.

Ultrastretchable, Ultralow Hysteresis, High-Toughness Hydrogel Strain Sensor for Pressure Recognition with Deep Learning.

Hydrogel, as a promising material for a wide range of applications, has demonstrated considerable potential for use in flexible wearable devices and engineering technologies. However, simultaneously realizing the ultrastretchability, low hysteresis, and high toughness of hydrogels is still a great challenge. Here, we present a dual physically cross-linked polyacrylamide (PAM)/sodium hyaluronate (HA)/montmorillonite (MMT) hydrogel. The introduction of HA increases the degree of chain entanglement, and the addition of MMT acts as a stress dissipation center and cross-linking agent, resulting in a hydrogel with high toughness and low hysteretic properties. This hydrogel synthesized by a simple strategy exhibited ultrahigh stretchability (3165%), high breaking stress (228 kPa), high toughness (4.149 MJ/m3), and ultralow hysteresis (≈2% at 100% of strain). The fabricated hydrogel flexible strain sensors possessed fast response and recovery times (62.5:75 ms), a wide strain detection range (2000%), a strain detection limit of 1%, and excellent cycling stability over 500 cycles. Furthermore, the hydrogel flexible strain sensor can be used for human motion monitoring, gesture recognition, and pressure recognition assisted by deep learning algorithms, showing enormous promise for applications.

Spatially hybrid control of entanglement between atom and photon

In this study, we introduced a model utilizing a plasmonic nanostructure to modulate the entanglement between atoms and photons within a V-type atomic medium. This system is influenced by composite optical vortex light (COVL) and two incoherent pumping fields. The plasmonic nanostructure comprises dielectric nanospheres, which have been thoroughly investigated (Phys. Rev. B 106, 035419, 2022). By adjusting the orbital angular momentum (OAM) of COVL, we demonstrate that the nanostructure induces significant spatial variations in the degree of entanglement (DEM). Additionally, incorporating a weak incoherent pumping field affects the DEM profile within the hybrid system. Our findings reveal that the OAM of structured light can govern the spatial dependence of DEM, particularly when quantum interference from the nanostructure and pumping fields surpasses a specific threshold. Furthermore, our results suggest that analyzing the DEM profile's spatial regions can be employed to determine the OAM number of the structured light.

Entanglement in Bound States of Two Particles with a Localized Center-of-Mass Wave-Function

Abstract We explore some entanglement-related features of systems consisting of two particles coupled through a central potential. We consider two types of systems, constituted by particles in one spatial dimension interacting through an attractive Dirac Delta potential, or through a harmonic quadratic potential. The degree of freedom corresponding to the system’s center of mass is either regarded as confined within a one dimensional box, or described by a localized Gaussian wave-packet. As a quantitative indicator of the degree of entanglement between the particles, we use the linear entropy of the one-particle marginal density matrix. In general, this quantity cannot be calculated analytically (except in some special cases related to the Harmonic interaction). Consequently, the linear entropy has to be evaluated numerically. Since the concomitant numerical problem consist in evaluating a multi-dimensional integral in four dimensions, the Monte Carlo integration method is an appropriate one for this task. We explore numerically how the system’s entanglement depends on the different interaction potentials, on the different types of confinement for the system’s center of mass, and on the associated parameters describing the size and geometry of the system.

Deciphering the role of FI catalyst’s C3 substituent on the non-isothermal crystallization kinetics of nascent disentangled UHMWPE

UH1 - UH4 were accessed using tetra-fluorinated phenoxy-imine catalysts (FI catalysts) with linear (allyl, n-propyl, 1-propenyl) or more steric demanding (isopropyl) C3 substituents ortho to the phenoxy-oxygen atom. To get a better understanding of the non-isothermal crystallization kinetics of these nascent ultra-high molecular weight polyethylenes (UHMWPEs), their thermo-rheological properties are investigated. Through the application of annealing-crystallization-melting thermal analysis and isoconversional method, it is verified that the samples are nascent disentangled UHMWPEs with higher crystallization rates compared to the commercial UHMWPE (CUH). The molar fraction of nascent entangled crystals and/or degree of supercooling have a significant influence on the non-isothermal crystallization kinetics of nascent disentangled UHMWPEs. Finally, under a lower supercooling, the electron-donating property and steric hindrance of C3 substituent strongly affect the synthesis and architecture of polyolefin which in turn has a specific non-isothermal crystallization kinetics.

Loss resilience of driven-dissipative remote entanglement in chiral waveguide quantum electrodynamics

Establishing limits of entanglement in open quantum systems is a problem of fundamental interest, with strong implications for applications in quantum information science. Here, we study the limits of entanglement stabilization between remote qubits. We theoretically investigate the loss resilience of driven-dissipative entanglement between remote qubits coupled to a chiral waveguide. We find that by coupling a pair of storage qubits to the two driven qubits, the steady state can be tailored such that the storage qubits show a degree of entanglement that is higher than what can be achieved with only two driven qubits coupled to the waveguide. By reducing the degree of entanglement of the driven qubits, we show that the entanglement between the storage qubits becomes more resilient to waveguide loss. Our analytical and numerical results offer insights into how waveguide loss limits the degree of entanglement in this driven-dissipative system, and they offer important guidance for remote entanglement stabilization in the laboratory, for example using superconducting circuits. Published by the American Physical Society 2024

Polarization-entangled photon-pair source with van der Waals 3R-WS2 crystal

Ultracompact entangled photon sources are pivotal to miniaturized quantum photonic devices. Van der Waals (vdW) nonlinear crystals promise efficient photon-pair generation and on-chip monolithic integration with nanophotonic circuitry. However, it remains challenging to generate maximally entangled Bell states of photon pairs with high purity, generation rate, and fidelity required for practical applications. Here, we realize a polarization-entangled photon-pair source based on spontaneous parametric down conversion in an ultrathin rhombohedral tungsten disulfide (3R-WS2) crystal. This vdW entangled photonic source exhibits a high photon-pair purity with a coincidence-to-accidental ratio of above 800, a generation rate of 31 Hz, and two maximally polarization-entangled Bell states with fidelities exceeding 0.93 and entanglement degree over 0.97. These results stem from scalable optical nonlinearity, enhanced second-order susceptibility by electronic transitions, and a well-defined symmetry-enabled selection rule inherent in 3R-WS2. Our polarization entangled photon source can be integrated with photonic structures for generating more complex entangled states, thus paving an avenue for advanced quantum photonic systems toward computation and metrology.

Dynamics of a two-qubit Tavis-Cummings model in the presence of an Ising-type interaction between qubits

In this paper, we investigated the dynamics of entanglement of two qubits interacting non-resonantly with the thermal field of a one-mode lossless resonator, taking into account the Ising-type direct interaction between qubits. Based on the exact solution of the quantum Liouville equation, we found the density matrix of the system under consideration. With its help, the reduced qubit-qubit density matrix was calculated and the entanglement criteriоn of the two-qubit system, Pres-Horodeсki parameter, was found. It was shown that for the resonance model and separable initial states of qubits, the direct interaction of qubits leads to a significant increase in the maximum degree of their entanglement. It was also found that for the nonresonant interaction between qubits and field, the increase of the maximum degree of entanglement of qubits is much greater than that due to direct interaction. For the original entangled Bell-type state of the qubits, the direct interaction was found to lead to the vanishing of the effect of the sudden death of entanglement in the case of a resonant qubit-field interaction and, conversely, to an increase in this effect for a nonresonant interaction.

Influence of Fractional and Decay Parameters on the SU(1,1) Quantum System Interaction with Three‐Level Atom

AbstractThrough the generalized fractional derivative, it is studied how the decay term and the fractional parameter affect the quantum system, specifically the interaction between the SU(1,1) algebraic system and a three‐level atom. By transforming the differential equations into fractional differential equations, general fractional solutions are obtained. The influence of decay and fractional parameter on phenomena such as revival and collapse, entropy squeezing, purity, and concurrence are investigated. The results demonstrate how both decay and fractal parameter affect periods of collapse and revival. It is worth noting that the decay parameter shortens the collapse periods, while an increase in the fractional parameter leads to longer collapse periods. The decay parameter also reduces the degree of entanglement between the different components of the quantum system, while increasing the fractional parameter enhances the entanglement within the quantum system. Hence, it can be concluded that the fractional parameter plays a crucial role in the observed effects on the studied properties.

Chip breakage assisted by pulsed high-pressure jet during continuous cylindrical turning 42CrMo steel

Continuous high-pressure jet technology (CHPJ) is often used to break chips during turning. However, the chip-breaking effect is not satisfactory in turning high-strength and high-toughness materials with a small depth of cut. In this research, a pulsed high-pressure jet assisted chip breaking technology (PHPJ) is proposed based on the water hammer effect. Then, a set of PHPJ equipment with stable working performance and safety was developed. The chip length and chip curling radius were selected as the chip breakage indexes under various depths of cut (0.3, 0.4, 0.5 mm) and jet pressures (10, 20, 30 bar). The improvement of chip-breaking ability of PHPJ was firstly reflected in the reduction of chip entanglement degree and chip length. The chip length under PHPJ was decreased by at least 13 % compared to that under CHPJ. Secondly, the PHPJ could reduce the chip curling radius by 3.48–23.36 % compared to CHPJ. The compression effect of chip curling of PHPJ relative to CHPJ showed a trend of firstly increasing and then decreasing as the jet pressure increases, with a turning point of 20 bar. Moreover, the PHPJ technology exhibited a positive influence on tool wear and machined surface quality.