Quantum Entanglement Effects Research Articles

Influence of the ionospheric sporadic E layer on the performance of quantum satellite communication in the mid latitude region

Quantum communication is a brand new way of communicating, in which the quantum entanglement effect is used to transmit information. Quantum communication is a new interdisciplinary subject between quantum theory and information theory. It has advantages of perfect information security and higher efficiency in transmission. The successful launch of the first quantum satellite named Micius laid an important foundation forconstructing a secure quantum communication network on a global scale. On the other hand, in the process of quantum satellite communication, the atmospheric environment near the ground will have a certain influence on the transmission of quantum signals, so the security of quantum communication is reduced. One of the influence factors is the ionospheric sporadic E layer. In the actual quantum communication environment, when the weak coherent state light source is simulated the single photon, the source energy is attenuated if the quantum signal passes through the ionosphere. On a space scale of 80-150 km off the ground, the ionospheric sporadic E layer is an irregular thin layer, in which there occurs a sharp increase of electron density under the action of wind shear. Sporadic E layer has a great influence on quantum satellite signal transmission. However, the research about the relationship between the sporadic E layer and quantum communication channel parameters has not yet conducted. To investigate the influence of the ionospheric sporadic E layer on the performance of quantum satellite communication, sporadic E layer formation process is first analyzed. And then the relationship between the free electron density and the height is obtained. After that, the model of the free electron density, the formation thickness and the link attenuation of quantum satellite is established. According to the amplitude damping channel, the quantitative relationships among free electron density and the channel capacity, entanglement fidelity, the quantum bit error rate and the secure key rate are put forward and simulated finally. Theoretical analysis and simulation results show that when the thickness is 1 km, the electron density increases from 3105 cm-1 to 27105 cm-1, the channel capacity decreases from 0.8304 to 0.1319, the entanglement fidelity decreases from 0.9386 to 0.3606, the quantum bit error rate increases from 0.0093 to 0.0769, and the secure key production rate decreases from 9.96810-5 to 1.9110-6. It can be shown that the electron density and the thickness of sporadic E layer have significant effect on the performance of quantum satellite communication. Therefore, in the process of quantum satellite communication, in order to ensure the reliability of quantum communication, based on the detection of ionosphere parameters, the various indexes of the satellite system should be adjusted adaptively.

Research on the Construction of the Universe Network Based on Quantum Entanglement Effect

Quantum communication is the current hot topic of complex networks. This article discusses interactions between various fields in quantum field theory, relationship between Compton wavelength and Schwarzschild radius, and the impact of quantum entanglement effect on everything in the universe, proposes the idea of using the quantum entanglement effect to construct the network system of the interconnection and interworking between people and everything. The main study of the induced relationship between quantum entanglements with the life body, the non-living body, the influence of quantum fluctuations on the quantum vibrations of the life body or the non-life body which is entangled with it, as well as the correlation between thinking consciousness and quantum entanglement. Focuses on the feasibility of constructing the universal network by the entanglement of quantum into the system of human and object. In this paper, we put forward the following points: the universe is a physical entity constructed by various substances, consciousness in the quantum level, in the micro field of natural existence. Quantum entanglement can influence an organism’s thinking consciousness and thinking consciousness of organisms can also be interference of quantum vibration, thus changing the original appearance of the related things. But inanimate objects, only by the most basic inductive relation of quantum entanglement, so only the most basic thinking consciousness. Discussed the quantum entanglement with the life body, non-life body associated technologies and methods. Final analysis of the construction of such a complex network of existing technical problems and safety issues, and prospects for future development.

Quantum melting of magnetic order in an organic dimer Mott-insulating system

Quantum entanglement effects between the electronic spin and charge degrees of freedom are examined in an organic molecular solid, termed a dimer-Mott insulating system, in which molecular dimers are arranged in a crystal as fundamental units. A low energy effective model includes an antisymmetric exchange interaction, as one of the dominant magnetic interactions. This interaction favors a 90 degree spin configuration, and competes with the Heisenberg-type exchange interaction. Stabilities of the magnetic ordered phases are examined by using the spin-wave theory, as well as the Schwinger-boson theory. It is found that the spin-charge interaction promotes an instability of the long-range magnetic ordered state around a parameter region where two spin-spiral phases are merged. Implication for the quantum spin liquid state observed in $\kappa$-(BEDT-TTF)$_2$Cu$_2$(CN)$_3$ is discussed.

Nonclassical effects in the second harmonic generation

The higher-order nonclassical squeezing and quantum entanglement effects emerging from the second harmonic generation of the associated two-mode and two-photon Hamiltonian are investigated in the dispersive limit. The squeezed states of the field, including the normal and amplitude squared (higher-order) squeezing factors are generated in two ways, i.e., from the bosonic operators via amplitude powered quadrature variables, and through the SU(2) characterization of a passive and lossless device with two input and two output ports, which then allows one to visualize the operations of beam splitters and phase shifters as rotations of angular momentum operators in 3-space. Two criteria for intermodal higher-order quantum entanglement and different coherent states for the two modes in the initial state are used to compute these nonclassical effects. The unitary time evolution of the linear entropy, computed from the partial trace of the density matrix over the secondary mode, is also used as a criterion of quantum entanglement. These approaches show, in fact, that the present model exhibits a considerable amount of this nonclassical effect. The unitary time evolution of the linear entropy shows that the present nonlinear optical model does not preserve the modulus of the Bloch vector.

Spin-Directed Momentum Transfers in SIDIS Baryon Production

The measurement of transverse single-spin asymmetries for baryon production in the target fragmentation region of semi-inclusive deep-inelastic scattering (SIDIS), can produce important insight into those nonperturbative aspects of QCD directly associated with confinement and with the dynamical breaking of chiral symmetry. We discuss here, interns of spin-directed momentum transfers, the powerful quantum field-theoretical constraints on the spin-orbit dynamics underlying these transverse spin observables. The spin-directed momentum shifts, originating either in the target nucleon or in the QCD jets produced in the deep inelastic scattering process, represent significant quantum entanglement effects connecting information from current fragmentation with observables in target fragmentation.

Absence of Jahn−Teller transition in the hexagonal Ba3CuSb2O9 single crystal

With decreasing temperature, liquids generally freeze into a solid state, losing entropy in the process. However, exceptions to this trend exist, such as quantum liquids, which may remain unfrozen down to absolute zero owing to strong quantum entanglement effects that stabilize a disordered state with zero entropy. Examples of such liquids include Bose-Einstein condensation of cold atoms, superconductivity, quantum Hall state of electron systems, and quantum spin liquid state in the frustrated magnets. Moreover, recent studies have clarified the possibility of another exotic quantum liquid state based on the spin-orbital entanglement in FeSc2S4. To confirm this exotic ground state, experiments based on single-crystalline samples are essential. However, no such single-crystal study has been reported to date. Here, we report, to our knowledge, the first single-crystal study on the spin-orbital liquid candidate, 6H-Ba3CuSb2O9, and we have confirmed the absence of an orbital frozen state. In strongly correlated electron systems, orbital ordering usually appears at high temperatures in a process accompanied by a lattice deformation, called a static Jahn-Teller distortion. By combining synchrotron X-ray diffraction, electron spin resonance, Raman spectroscopy, and ultrasound measurements, we find that the static Jahn-Teller distortion is absent in the present material, which indicates that orbital ordering is suppressed down to the lowest temperatures measured. We discuss how such an unusual feature is realized with the help of spin degree of freedom, leading to a spin-orbital entangled quantum liquid state.

Renormalization of myoglobin–ligand binding energetics by quantum many-body effects

We carry out a first-principles atomistic study of the electronic mechanisms of ligand binding and discrimination in the myoglobin protein. Electronic correlation effects are taken into account using one of the most advanced methods currently available, namely a linear-scaling density functional theory (DFT) approach wherein the treatment of localized iron 3d electrons is further refined using dynamical mean-field theory. This combination of methods explicitly accounts for dynamical and multireference quantum physics, such as valence and spin fluctuations, of the 3d electrons, while treating a significant proportion of the protein (more than 1,000 atoms) with DFT. The computed electronic structure of the myoglobin complexes and the nature of the Fe-O2 bonding are validated against experimental spectroscopic observables. We elucidate and solve a long-standing problem related to the quantum-mechanical description of the respiration process, namely that DFT calculations predict a strong imbalance between O2 and CO binding, favoring the latter to an unphysically large extent. We show that the explicit inclusion of the many-body effects induced by the Hund's coupling mechanism results in the correct prediction of similar binding energies for oxy- and carbonmonoxymyoglobin.

Application of Non-Equilibrium Thermo Field Dynamics to quantum teleportation under the environment

Quantum teleportation for continuous variables is treated by Non-Equilibrium Thermo Field Dynamics (NETFD), a canonical operator formalism for dissipative quantum systems, in order to study the effect of imperfect quantum entanglement on quantum communication. We used an entangled state constructed by two squeezed states. The entangled state is imperfect due to two reasons, i.e., one is the finiteness of the squeezing parameter r and the other comes from the process that the squeezed states are created under the dissipative interaction with the environment. We derive the expressions for one-shot fidelity (OSF), probability density function (PDF) associated with OSF and (averaged) fidelity by making full use of the algebraic manipulation of operator algebra within NETFD. We found that OSF and PDF are given by Gaussian forms with its peak at the original information α to be teleported, and that for r≫1 the variances of these quantities blow up to infinity for κ/χ≤1, while they approach to finite values for κ/χ>1. Here, χ represents the intensity of a degenerate parametric process, and κ the relaxation rate due to the interaction with the environment. The blow-up of the variances for OSF and PDF guarantees higher security against eavesdropping. With the blow-up of the variances, the height of PDF reduces to small because of the normalization of probability, while the height of OSF approaches to 1 indicating a higher performance of the quantum teleportation. We also found that in the limit κ/χ≫1 the variances of both OSF and PDF for any value of r (>0) reduce to 1 which is the same value as the case r=0, i.e., no entanglement.

Multiparty Zero-Error Classical Channel Coding With Entanglement

We study the effects of quantum entanglement on the performance of two classical zero-error communication tasks among multiple parties. Both tasks are generalizations of the two-party zero-error channel-coding problem, where a sender and a receiver want to perfectly communicate messages through a one-way classical noisy channel. If the two parties are allowed to share entanglement, there are several positive results that show the existence of channels for which they can communicate strictly more than what they could do with classical resources. In the first task, one sender wants to communicate a common message to multiple receivers. We show that if the number of receivers is greater than a certain threshold then entanglement does not allow for an improvement in the communication for any finite number of uses of the channel. On the other hand, when the number of receivers is fixed, we exhibit a class of channels for which entanglement gives an advantage. The second problem we consider features multiple collaborating senders and one receiver. Classically, cooperation among the senders might allow them to communicate on average more messages than the sum of their individual possibilities. We show that whenever a channel allows single-sender entanglement-assisted advantage, then the gain extends also to the multi-sender case. Furthermore, we show that entanglement allows for a peculiar amplification of information which cannot happen classically, for a fixed number of uses of a channel with multiple senders.

Unravelling the quantum-entanglement effect of noble gas coordination on the spin ground state of CUO

The accurate description of the complexation of the CUO molecule by Ne and Ar noble gas matrices represents a challenging task for present-day quantum chemistry. Especially, the accurate prediction of the spin ground state of different CUO--noble-gas complexes remains elusive. In this work, the interaction of the CUO unit with the surrounding noble gas matrices is investigated in terms of complexation energies and dissected into its molecular orbital quantum entanglement patterns. Our analysis elucidates the anticipated singlet--triplet ground-state reversal of the CUO molecule diluted in different noble gas matrices and demonstrates that the strongest uranium-noble gas interaction is found for CUOAr4 in its triplet configuration.

Resonant dipole–dipole interaction in confined and strong-coupling dielectric geometries

Using the electromagnetic response function of an electric dipole located within a dielectric geometry, we derive the mathematical equivalence between the classical response and quantum mechanical resonant dipole–dipole interaction between two quantum objects (atoms, quantum dots, etc). Cooperative spontaneous emission likewise emerges from this equivalence. We introduce a practical numerical technique using finite difference time domain for calculating both dipole–dipole interaction and collective spontaneous emission in confined dielectric structures, where strong light–matter coupling might arise. This method is capable of obtaining resonant dipole–dipole interaction over a wide range of frequencies in a single run. Our method recaptures the results of quantum mechanical second order perturbation theory for weak light–matter coupling. In strong coupling situations such as near a photonic band edge, second order Rayleigh–Schrödinger perturbation theory leads to divergences, and instead Brillouin–Wigner perturbation theory is required. This is equivalent to the use of a variational wavefunction to describe the exciton transfer between initial and final states. We introduce a system of coupled classical oscillators, that describes resonant dipole–dipole interaction and vacuum Rabi splitting in the strong-coupling regime, and that provides an effective numerical scheme based on the finite difference time domain method. This includes the effects of quantum entanglement and the correlation of quantum fluctuations. We discuss the crossover to Forster energy transfer when quantum correlations between the dipoles are damped by strong environmental interactions.

Revealing the Ubiquitous Effects of Quantum Entanglement—Toward a Notion of God Logic

Following Spinoza-Einstein’s interpretation of God or nature, the notion “God Logic” is proposed. This notion is to serve as an elicitation for a consistent set of necessary criteria for: 1) developing the logical foundation of quantum gravity as envisaged by Einstein, 2) revealing the ubiquitous effects of quantum entanglement as suggested by Roger Penrose, and 3) programming the universe as proposed by Seth Lloyd. An evolving set of eleven criteria is proposed for the notion. The possibility of inventing such a logical system is analyzed. A supersymmetrical candidate logic of negative-positive energy dynamic equilibrium is introduced and assessed against the set of criteria. It is shown that the first 10 criteria are met or partially met by the candidate. But the question whether the 11 th criterion has been or can be met is left open for discussion and further research effort. The assessment leads to a few predictions. Notably, it is predicted that, should Boson-Fermion symmetry or broken symmetry be observed, it would be caused by bipolar symmetry or broken symmetry of negative-positive energies.

Final state effects in the neutron Compton scattering on hydrogen molecules—a new approach

Compton scattering on hydrogen molecules (H2, D2) with neutrons in the 10–100eV range has recently been discussed in connection with observations of certain unexplained shifts of the Compton peaks at higher scattering angles (possibly indicating a quantum entanglement effect on the sub-fs-time scale). It is therefore worthwhile to look somewhat deeper into the details of the scattering process for these particular systems. One main aspect is the specific situation valid for two-atomic molecules where the vibrational momenta lie only along the molecular axes, another concerns the validity of the impulse approximation and a third main aspect is related to the anomalous cross-sections in the H/D intensity ratios observed for mixed H2/D2 samples.In an alternative treatment of the so-called final state (FSE) effects the concept of scattering time is analyzed and the elastic slowing-down of the recoiling protons during this time is explicitly calculated and compared, first with those expected from standard FSE calculations and then with experimental data for one specifically chosen, well-studied system, the D2 molecule. The results of the present FSE calculations differ from the standard ones in the high energy tail of the Compton peak, but agrees very well with experiment. Taking into account the line shape differences discussed here should also be of importance for the closer analysis of proton momentum distributions as well as for the interpretation of the H- and D- intensity anomalies.

Quantum field, interference, and entanglement effects in nonlinear optical spectroscopy

Experimental observables in quantum systems may be represented by Liouville space pathways which describe the evolving density matrix. The pathways of coupled degrees of freedom may become entangled leading to interesting interference effects. We demonstrate and classify signatures of these quantum effects in optical measurements which involve both classical and quantum modes of the radiation field. Generalized response functions recast in terms of superoperators are used to provide a compact unified description of a broad range of measurements. We discuss interferences of quantum pathways of matter related to the entanglement of excitons in chromophore aggregates, and how they can be manipulated by interactions with quantum optical fields.

Computer modeling of hydrogen fuel cell subsystems: Carbon nanogel electrodes and fractal nanoparticle catalysts

This article deals with nonequilibrium self-assembling and self-organizing processes of multilevel synthesis of hydrogen anode that are considered employing the methods computational nanotechnology. These processes include femtosecond quantum entanglement processing of carbon nanogel electrodes and fractal nanoparticle catalysts. This article also analyzes the results of the computer imitation of algorithmic nanoengineering of multilevel designing inside anode’s nanopore of carbon nanogel nanocomposite with Ni nanoparticle catalysts. There are three levels of multilevel synthesis processing: quantum dynamics of atoms, quantum entanglement dynamics of nanosystems and classical dynamics of micropour systems. They obey the principals of self-assembling and self-organization on the level of nanosystems, that is the most basic one for self-managing operations. It demands the application of the most difficult quantum computer processing because of the corporative effects of quantum entanglement, which comply with specific quantum information processing.

Quantum physics meets biology.

Quantum physics and biology have long been regarded as unrelated disciplines, describing nature at the inanimate microlevel on the one hand and living species on the other hand. Over the past decades the life sciences have succeeded in providing ever more and refined explanations of macroscopic phenomena that were based on an improved understanding of molecular structures and mechanisms. Simultaneously, quantum physics, originally rooted in a world-view of quantum coherences, entanglement, and other nonclassical effects, has been heading toward systems of increasing complexity. The present perspective article shall serve as a "pedestrian guide" to the growing interconnections between the two fields. We recapitulate the generic and sometimes unintuitive characteristics of quantum physics and point to a number of applications in the life sciences. We discuss our criteria for a future "quantum biology," its current status, recent experimental progress, and also the restrictions that nature imposes on bold extrapolations of quantum theory to macroscopic phenomena.

Quantum and Classical Glass Transitions inLiHoxY1−xF4

When performed in the proper low-field, low-frequency limits, measurements of the dynamics and the nonlinear susceptibility in the model Ising magnet in a transverse field LiHo(x)Y(1-x)F(4) prove the existence of a spin-glass transition for x=0.167 and 0.198. The classical behavior tracks for the two concentrations, but the behavior in the quantum regime at large transverse fields differs because of the competing effects of quantum entanglement and random fields.

Cosmological avatars of the landscape. I. Bracketing the supersymmetry breaking scale

We investigate the effects of quantum entanglement between our horizon patch and others due to the tracing out of long wavelength modes in the wave function of the Universe as defined on a particular model of the landscape. In this, the first of two papers devoted to this topic, we find that the SUSY breaking scale is bounded both above and below: ${10}^{\ensuremath{-}10}{M}_{\mathrm{P}}\ensuremath{\le}{M}_{\mathrm{SUSY}}\ensuremath{\le}{10}^{\ensuremath{-}8}{M}_{\mathrm{P}}$ for grand unified theory (GUT) scale inflation. Bounds on the SUSY breaking parameter depend on the scale of inflation. If inflation occurred at GUT energies, the lower bound on $b$ is at least 5 orders of magnitude larger than the expected value of this parameter, soon to be tested by LHC.

Studies on electron spin resonance spectroscopy of biradical molecules containing 14N-O and 15N-O moieties

The biradicals with 14N-Oxide and 15N-Oxide at the both ends of a molecule are synthesized for the molecular ruler of protein structure, and a potential device for quantum computing. We also establish a general synthetic method for reliable biradical formation. ESR spectra are recorded for the biradicals containing 15N-Oxide and 14N-Oxide with various interdistance separations. We find that two types of biradicals yielded different ESR spectra depending upon the distance between the 15N-O and 14N-O moieties in a molecule. This is due to electron spin dipole–dipole interaction occurring between the radicals. We also find that there is an indication of isotopic nuclear effects in the dipole–dipole interactions. The present study implies feasibility of the distance measurement between two different N-Oxides containing 14N and 15N isotopes. We conclude that quantum entanglement effects are observed through the dipolar interactions, which enable application of quantum computing devices operating in the liquid state.

Construction and analysis of a simplified many-body neutrino model

In dense neutrino systems, such as found in the early Universe, or near a supernova core, neutrino flavor evolution is affected by coherent neutrino-neutrino scattering. It has been recently suggested that many-particle quantum entanglement effects may play an essential role in these systems, potentially invalidating the traditional description in terms of a set of single-particle evolution equations. We model the neutrino system by a system of interacting spins, following an earlier work which showed that such a spin system can in some cases be solved exactly [A. Friedland and C. Lunardini, J. High Energy Phys. 10 (2003) 043.]. We extend this work by constructing an exact analytical solution to a more general spin system, including initial states with asymmetric spin distribution and, moreover, not necessarily aligned along the same axis. Our solution exhibits a rich set of behaviors, including coherent oscillations and dephasing and a transition from the classical to quantum regimes. We argue that the classical evolution of the spin system captures the entire coherent behavior of the neutrino system, while the quantum effects in the spin system capture some, but not all, of the neutrino incoherent evolution. By comparing the spin and neutrino systems, we find no evidence for the violation of the accepted one-body description, though the argument involves some subtleties not appreciated before. The analysis in this paper may apply to other two-state systems beyond the neutrino field.