The influences of dipole-dipole interaction and detuning on the sudden death of entanglement between two atoms in the Tavis-Cummings model

The influences of dipole-dipole interaction and detuning on the entanglement between two atoms with different initial tripartite entangled W-like states in the Tavis Cummings model have been investigated by means of Wootters＇ concurrence, respectively. The results show that the entanglement between the two atoms can be enhanced via appropriately tuning the strength of dipole-dipole interaction of two atoms or the detunings between atom and cavity, and the so-called sudden death effect can he weakened simultaneously.

Critical Property of the Geometric Phase in the Dicke Model with the Dipole-dipole Interactions

We obtained the ground-state energy level and associated geometric phase in the Dicke model with the dipoledipole interactions analytically by the Holstein-Primakoff transformation and the boson expansion approach in the thermodynamic limit. The nonadiabatic geometric phase induced by the photon field was derived with the time-dependent unitary transformation. It is shown that dipole-dipole interactions have a deep influence on scaled behavior of the geometric phase at the critical point.

Measurement-induced disturbance between two atoms in Tavis-Cummings model with dipole dipole interaction

Quantum correlation, measured by measurement-induced disturbance （MID）, between two two-level atoms is investi- gated in detail in Tavis-Cummings model with dipole--dipole interaction （DDI）. We find that MID can be determined only by the dipole-dipole interaction between the two atoms when the cavity and atoms are at resonance. Moreover, DDI will have different effects on MID for two different kinds of initial states.

Constraining Isovector Nuclear Interactions with Giant Dipole Resonance and Neutron Skin in ^(208)Pb from a Bayesian Approach

The remaining uncertainties in relation to isovector nuclear interactions call for reliable experimental measurements of isovector probes in finite nuclei.Based on the Bayesian analysis,although neutron-skin thickness data or isovector giant dipole resonance data in ^(208)Pb can constrain only one isovector interaction parameter,correlations among other parameters can also be built.Using combined data for both the neutron-skin thickness and the isovector giant dipole resonance helps to significantly constrain all isovector interaction parameters;as such,it serves as a useful methodology for future research.

Position-dependent property of resonant dipole-dipole interaction mediated by localized surface plasmon of an Ag nanosphere

We use the photon Green-function method to study the quantum resonant dipole-dipole interaction（RDDI） induced by an Ag nanosphere（ANP）.As the distance between the two dipoles increases,the RDDI becomes weaker,which is accompanied by the influence of the higher-order mode of the ANP on RDDI declining more quickly than that of the dipole mode.Across a broad frequency range（above 0.05 eV）,the transfer rate of the RDDI is nearly constant since the two dipoles are fixed at the proper position.In addition,this phenomenon still exists for slightly different radius of the ANPs.We find that the frequency corresponding to the maximum transfer rate of RDDI exhibits a monotonic decrease by moving away one dipole as the other dipole and the ANP are kept fixed.In addition,the radius of ANP has little effect on this.When the two dipoles are far from the ANP,the maximum transfer rate of the RDDI takes place at the frequency of the dipole mode.In contrast,when the two dipoles are close to the ANP,the higher-order modes come into effect and they will play a leading role in the RDDI if they match the transition frequency of the dipole.Our results may be used in a biological detector and have a certain guiding significance for further application.

Effects of dipole-dipole interaction on entanglement transfer

A system consisting of two different atoms interacting with a two-mode vacuum, where each atom is resonant only with one cavity mode, is considered. The effects of dipole-dipole （dd） interaction between two atoms on the atom-atom entanglement and mode--mode entanglement are investigated. For a weak dd interaction, when the atoms are initially separable, the entanglement between them can be induced by the dd interaction, and the entanglement transfer between the atoms and the modes occurs efficiently; when the atoms are initially entangled, the entanglement transfer is almost not influenced by the dd interaction. However, for a strong dd interaction, it is difficult to transfer the entanglement from the atoms to the modes, but the atom-atom entanglement can be maintained when the atoms are initially entangled.

Manipulation of nonreciprocal unconventional photon blockade in a cavity-driven system composed of an asymmetrical cavity and two atoms with weak dipole–dipole interaction

We present a work of manipulating collective unconventional photon blockade(UCPB)and nonreciprocal UCPB(NUCPB)in a cavity-driven system composed of an asymmetrical single-mode cavity and two interacting identical twolevel atoms(TLAs).When the atoms do not interact directly,the frequency and intensity restrictions of collective UCPB can be specified,and a giant NUCPB exists due to the splitting of optimal atom–cavity coupling strength in proper parameter regime.However,if a weak atom–atom interaction which provides a new and feeble quantum interference pathway to UCPB is taken into account,two restrictions of UCPB are combined complexly,which are rigorous to be matched simultaneously.Due to the push-and-pull effect induced by weak dipole–dipole interaction,the UCPB regime is compressed more or less.NUCPB is improved as a higher contrast is present when the two complex UCPB restrictions are matched,while it is suppressed when the restrictions are mismatched.In general,whether NUCPB is suppressed or promoted depends on its working parameters.Our findings show a prospective access to produce giant quantum nonreciprocity by a couple of weakly interacting atoms.

Analysis of Electrical Dipoles Interaction Forces as a Function of the Distance and of the Form of Electrical Force Law

Here, we initially introduced and demonstrated two principles: orientation OR principle and attraction AT principle of electrical dipoles. The OR principle stipulates that any two electrical dipoles P1A, P1B, from two bodies A and B, at any distance in the free state each, will be reciprocally oriented parallel and in the same sense if the electrical interaction forces F between them are of decreasing type with distance r. If the electrical interaction forces F are of increasing type with distance, the two dipoles will be reciprocally oriented parallel but on the opposite sense. The AT principle stipulate that any two electrical dipoles P1A, P1B, at any distance in the free state each, will present always a reciprocal force of attraction FD in both cases of orientation accordingly to OR principle in case of any type of electrical force F decreasing or increasing with distance. These findings may complete our previous work where we found that FD force, between two electrical dipoles P1A, P1B considered at atomic and nuclear level, is in fact the actual gravitation Newton force FN. The paper must be considered together with this work for more consistency.

Dipole–dipole interactions enhance non-Markovianity and protect information against dissipation

Preserving non-Markovianity and quantum entanglement from decoherence effect is of theoretical and practical significance in the quantum information processing technologies.In this context, we study a system S that is initially correlated with an ancilla A, which interacts with the environment E via an amplitude damping channel.We also consider dipole-dipole interactions(DDIs) between the system and ancilla, which are responsible for strong correlations.We investigate the impact of DDIs and detuning on the non-Markovianity and information exchange in different environments.We show that DDIs are not only better than detuning at protecting the information(without destroying the memory effect) but also induce memory by causing a transition from Markovian to non-Markovian dynamics.In contrast, although detuning also protects the information, it causes a transition from non-Markovian to the Markovian dynamics.In addition, we demonstrate that the non-Markovianity grows with increasing DDI strength and diminishes with increasing detuning.We also show that the effects of negative detuning and DDIs can cancel out each other, causing a certain loss of coherence and information.

Numerical Experiment for Dipole-Dipole Interaction in Electro-Magnetism with Help of a Regular Tetrahedron

Aim of this work is to try to explain, on a Rational basis, some equations of Electro-Magnetism, which are based on Experimental data. Any Electric Field can produce a Field of many small Electric Dipoles, continuously distributed in space. In a region, where the Electric Field is constant, in direction and magnitude, all the small Dipoles are parallel to the Electric Field, and are represented by a single, long, parallel to them, fixed in space, Electric Dipole, which is here called Compass. An Alternating current, in a straight Conductor, is studied, by a simple, short computer program, for step-by-step nonlinear dynamic analysis. It is found that, only an Alternating current, not a direct current, can produce an Electric Dipole, in a straight Conductor. The two above Dipoles (Compass-Conductor) are assumed with equal lengths ℓ, lying on two skew lines, perpendicular to each other, at a distance ℓ√2, thus forming, by their four ends, a Regular Tetrahedron, with side length ℓ. Repulsion, between Like Charges, obeys the simple Coulomb Electro-Static law. Whereas Interaction (Attraction or Repulsion), between Unlike Charges, obeys a more accurate Lennard-Jones law. The analysis of Dipole-Dipole (Compass-Conductor) Interaction is performed by hand calculator. The only out-of-balance forces, in the regular Tetrahedron, acting on the Rigid Conductor, are the so-called magnetic forces. Their direction is found, in a simple Rational way, with help of Regular Tetrahedron, without recoursing to a “right-hand-rule”. The proposed model is applied to 1) The force acting on an Electric Charge moving in a magnetic field. 2) The force acting on a Current carrying straight Conductor, due to a magnetic field. 3) The magnetic fields created around a Current carrying straight Conductor. In these applications, proposed model gives reasonable results. Particularly, in third application, results, obtained by proposed model, are found in satisfactory approximation with corresponding ones, obtained by an empirical formula, based on relevant Experimental observations of H.-C. Oersted and A.-M. Ampère. So, the reliability of proposed model is checked. Position and direction of magnetic field vector coincide with those of a corresponding fixed Compass of a constant Electric Field. Main point of present work is that, without introducing the concept of a magnetic field vector, by combining field of dipoles, produced by an electric field, with dipole of an alternating current carrying conductor, the magnetic forces can be determined.

The Role of the Dipole Interaction of Molecules with Charged Particles in the Polar Stratosphere

Our analysis of published results of experiments in the Polar Regions substantiates and further develops our new approach to the photochemical processes in the polar stratosphere involving the charged particles. The dipole interaction of molecules with charged particles, primarily with ions, leads to the adhesion and disintegration of a number of molecules including ozone. Molecules acquire additional energy on the surface of the charged particles, enabling reactions that are not possible in space. Galactic cosmic rays are the main source of ions in the polar stratosphere, their equilibrium concentration at altitudes of 15 to 25 km can reach up ~ （1-5） ~ 103 ions/cm3. Estimations show that if the ozone destruction in the regime of＂collision＂ with ions then the lifetime of ozone will vary from 10 days to 2 months. We suppose that alongside with the chlorine mechanism of ozone destruction there is a mechanism of ozone decay on a charged particle which can act also at those latitudes and altitudes where chlorine oxide CIO is absent, as well as in the night conditions. Here, we demonstrated the close connection of photochemical processes with the dynamic, electrical and condensational phenomena in the stratosphere, in particular, with the accumulation of unipolar charged particles on the upper and lower boundaries of the polar stratospheric clouds and aerosol layers as a result of the activity of the global electric circuit.

Dynamic Dipole-Dipole Magnetic Interaction and Damped Nonlinear Oscillations

Static dipole-dipole magnetic interaction is a classic topic discussed in electricity and magnetism text books. Its dynamic version, however, has not been reported in scientific literature. In this article, the author presents a comprehensive analysis of the latter. We consider two identical permanent cylindrical magnets. In a practical setting, we place one of the magnets at the bottom of a vertical glass tube and then drop the second magnet in the tube. For a pair of suitable permanent magnets characterized with their mass and magnetic moment we seek oscillations of the mobile magnet resulting from the unbalanced forces of the anti-parallel magnetic dipole orientation of the pair. To quantify the observed oscillations we form an equation describing the motion of the bouncing magnet. The strength of the magnet-magnet interaction is in proportion to the inverse fourth order separation distance of the magnets. Consequently, the corresponding equation of motion is a highly nonlinear differential equation. We deploy Mathematica and solve the equation numerically resulting in a family of kinematic information. We show our theoretical model with great success matches the measured data.

Higher-Order Corrections to Algebraic Derivation of Electric Dipole-Dipole Interaction

Nucleons are fermions with intrinsic spins exhibiting dipole character. Dipole-dipole interaction via their dipole moments is the key feature quantifying the short-range nucleonics interaction in two-body physics. For a pair of interacting dipoles, the energy of a pair is the quantity of interest. The same is true for chemical polar molecules. For both cases, derivation of energy almost exclusively is carried out vectorially [1]. Although uncommon the interacting energy can be derived algebraically too. For the latter Taylor, expansion is applied [2]. The given expression although appears to be correct it is incomplete. In our report, by applying Taylor’s expansion up to the 4th order and utilizing a Computer Algebra System we formulate the missing terms. Our report highlights the impact of correcting missing terms by giving two explicit examples.

Moments of Inertia, Magnetic Dipole Moments, and Electric Quadrupole Moments of the Lithium Isotopes

The single-particle Schrödinger fluid model is designed mainly to calculate the moments of inertia of the axially symmetric deformed nuclei by assuming that each nucleon in the nucleus is moving in a single-particle potential which is deformed with time t, through its parametric dependence on a classical shape variable α(t). Also, the Nilsson model is designed for the calculations of the single-particle energy levels, the magnetic dipole moments, and the electric quadrupole moments of axially symmetric deformed nuclei by assuming that all the nucleons are moving in the field of an anisotropic oscillator potential. On the other hand, the nuclear superfluidity model is designed for the calculations of the nuclear moments of inertia and the electric quadrupole moments of deformed nuclei which have no axes of symmetry by assuming that the nucleons are moving in a quadruple deformed potential. Furthermore, the cranked Nilsson model is designed for the calculations of the total nuclear energy and the quadrupole moments of deformed nuclei which have no axes of symmetry by modifying the Nilsson potential to include second and fourth order oscillations. Accordingly, to investigate whether the six p-shell isotopes 6Li, 7Li, 8Li, 9Li, 10Li, and 11Li have axes of symmetry or not, we applied the four mentioned models to each nucleus by calculating their moments of inertia, their magnetic dipole moments, and their electric quadrupole moments by varying the deformation parameter β and the non-axiality parameter γ in wide ranges of values for this reason. Hence for the assumption that these isotopes are deformed and have axes of symmetry, we applied the single-particle Schrödinger fluid model and the Nilsson model. On the other hand, for the assumption that these isotopes are deformed and have no axes of symmetry, we applied the cranked Nilsson model and the nuclear super fluidity model. As a result of our calculations, we can conclude that the nucleus 6Li may be assumed to be deformed and has an axis of symmetry.

Intermodel Diversity of Simulated Long-term Changes in the Austral Winter Southern Annular Mode:Role of the Southern Ocean Dipole

The Southern Annular Mode(SAM)plays an important role in regulating Southern Hemisphere extratropical circulation.State-of-the-art models exhibit intermodel spread in simulating long-term changes in the SAM.Results from Atmospheric Model Intercomparison Project(AMIP)experiments from 28 models archived in CMIP5 show that the intermodel spread in the linear trend in the austral winter(June−July−August)SAM is significant,with an intermodel standard deviation of 0.28(10 yr)−1,larger than the multimodel ensemble mean of 0.18(10 yr)−1.This study explores potential factors underlying the model difference from the aspect of extratropical sea surface temperature(SST).Extratropical SST anomalies related to the SAM exhibit a dipole-like structure between middle and high latitudes,referred to as the Southern Ocean Dipole(SOD).The role of SOD-like SST anomalies in influencing the SAM is found in the AMIP simulations.Model performance in simulating the SAM trend is linked with model skill in reflecting the SOD−SAM relationship.Models with stronger linkage between the SOD and the SAM tend to simulate a stronger SAM trend.The explained variance is about 40%in the AMIP runs.These results suggest improved simulation of the SOD−SAM relationship may help reproduce long-term changes in the SAM.

rp Drell-Yan Process in Color Dipole Model

We study pion-proton Orp) Drell-Yan (DY) dilepton production in the target rest frame with color dipole model. The prediction for πp DY cross section at the energies of RHIC and LHC is presented, and it can be compared with the data directly, because it does not need K factor. At the same time, the transverse momentum distribution is shown in quantities, which is not available from the standard parton model. The experimental studies of the process could test the color model for DY dilepton production.

Research on the Static Magnetic Field of Ships with Corrosion and Anticorrosion Efficacy Using Electric Dipole Model

In the case of three-layered(air-seawater-seabed)model,the analytical expressions of the static electric and static magnetic field produced by the static electric dipole located in seawater were derived by using the mirror image theory.Combined with the distribution of the underwater electric potential measured in laboratory,an electric dipole model for physical scale of ship was established and the distribution characteristics of an actual ship' s corrosion related magnetic field were obtained.Based on established models,theoretical analysis and calculation were made to catch out the distribution characteristics of static magnetic field related with corrosion and anticorrosion,which can not be measured directly in seawater.The results show that the static magnetic field related with corrosion and anticorrosion is a kind of noteworthy obstacle signal for degaussed ships.

3-D Magnetic Sensor Module for Locating and Tracking MEMS Swallowable Capsule Based on Scalar Form of Magnetic Dipole Model

MEMS swallowable capsule is a novel technology in the non-invasive surgery. This technology provides a way to diagnose directly into the deep intestinal where the traditional invasive technology implemented, such as X-Ray, endoscopy. It is a key for us to locate and track the position of a MEMS capsule in clinical applications. To solve this problem, we implemented a magnetic sensor module based on the scalar form of the magnetic dipole model,which was designed with very small size （5.2 ＊ 2. 1 ＊ 1.2 em） and easy to assemble to satisfy the system requirement. Here we discuss in detail the principle of magnetic dipole model, rules of selecting sensor and functions of the module. Some trials are established to test the characteristic of the module. The results of the Cm experiment demonstrates that the module follows the rules of the new magnetic dipole model form.

Comparison between Equivalent Charge Model and Equivalent Dipole Model on Realistic Head Model

Equivalent source layer （ESL） imaging is an important kind of high-resolution electro- encephalogram （EEG） imaging. It consists of two categories： equivalent dipole layer （EDL） and equivalent charge layer （ECL）. Both of them are assumed to be located on or near the cortical surface and have been proposed as high-resolution imaging modalities or as intermediate steps to estimate the epicortical potential. Here, EDL and ECL based on a realistic head model are presented, both simulations and real data experiment are done to compare these two models. The results show that ECL can provide higher spatial resolution about source location than EDL does.

Influence of the North American Dipole on ENSO onset as simulated by a coupled ocean-Atmosphere model

The North American Dipole(NAD)is a north-south seesaw pattern of sea level pressure anomalies over the western tropical North Atlantic and northeastern North America.Previous observational studies have demonstrated that the NAD can affect the outbreak of El Niño-Southern Oscillation(ENSO)events.The present study analyzed the NAD-ENSO relationship as simulated by a coupled ocean-atmosphere model-namely,the Flexible Global Ocean-Atmosphere-Land System model,gridpoint version 2(FGOALS-g2).Results indicated that the model can replicate a distinct dipole comprised of a low over northeastern North America and a high over the western tropical North Atlantic,which is the signature feature of the NAD.Further analysis verified that the winter NAD can initiate the central equatorial Pacific warming in the subsequent winter by effectively forcing an anticyclonic flow and sea surface temperature(SST)warming over the northeastern subtropical Pacific(NESP)during late winter or early spring.In addition,the probability of an El Niño event was increased by a factor of 1.8 in the assimilation experiment with the NAD.By comparison,the winter Northern Atlantic Oscillation had no significant impact on the occurrence of ENSO a year later owing to its failure to induce the SST and surface wind anomalies over the NESP.