Screened Thermonuclear Reaction Rates on Magnetar Surfaces

Improving Salpeter＇s method, we discuss the effect of superstrong magnetic fields （such as those of magnetars） on thermonuclear reaction rates. These most interesting reactions, including the hydrogen burning by the CNO cycle and the helium burning by the triple alpha reaction, are investigated as examples on the magnetar surfaces. The obtained result shows that the superstrong magnetic fields can increase the thermonuclear reaction rates by many orders of magnitude. The enhancement may have significant influence for further study research of the magnetars, especially for the x-ray luminosity observation and the evolution of magnetars.     

The phases of isospin-asymmetric matter in the two-flavor NJL model

We investigate the phase diagram of isospin-asymmetric matter at T=0$T=0$ in the two-flavor Nambu–Jona-Lasinio model. Our approach describes the single nucleon as a confined quark–diquark state, the saturation properties of nuclear matter at normal densities, and the phase transition to normal or color superconducting quark matter at higher densities. The resulting equation of state of charge-neutral matter and the structure of compact stars are discussed.     

K0 Condensation in Hyperonic Neutron Star Matter

In the framework of the relativistic mean field theory, we investigate K^0 condensation along with K^- condensation in neutron star matter including the baryon octet. The results show that both K^0 and K^- condensations can occur well in the core of the maximum mass stars for relatively shallow optical potentials of K^- in the range of-100 MeV～ -160 MeV. With the increasing optical potential of K^-, the critical densities of K^- decrease and the species of baryons appearing in neutron stars become fewer. The main role of K^0 condensation is to make the abundances of particles become identical leading to isospin saturated symmetric matter including antikaons, nucleons and hyperons. K^- condensation is chiefly responsible for the softening of the corresponding equation of state, which leads to a large reduction in the maximum masses of neutron stars. In the core of massive neutron stars, neutron star matter including rich particle species, such as antikaons, nucleons and hyperons, may exist.     

Hot Nuclear Matter Equation of State and Finite Temperature Kaon Condensation

We perform a systematic calculation of the equation of state of asymmetric nuclear matter at finite temperature within the framework of the Brueckner-Hartree-Fock approach with a microscopic three-body force. When applying it to the study of hot kaon condensed matter, we find that the thermal effect is more profound in comparison with normal matter, in particular around the threshold density. Also, the increase of temperature makes the equation of state slightly stiffer through suppression of kaon condensation.     

Neutron stars in a Skyrme model with hyperons

Available Skyrme parametrizations with hyperons are examined from the point of view of their suitability for applications to neutron stars. It is shown that the hyperons can attenuate or even remove the problem of ferromagnetic instability common to (nearly) all Skyrme parametrizations of the nucleon-nucleon interaction. At high density the results are very sensitive to the choice of the interaction. The selected parameter sets are then used to obtain the resulting properties of both cold neutron stars and hot protoneutron stars. The general features known from other models are recovered.     

Gauss-Bonnet and Lovelock Gravities and the Generalized Second Law of Thermodynamics

It has been shown [Chin. Phys. Lett.25 （2008） 4199] that the generalized second law of thermodynamics holds in Einstein gravity. Here we extend this procedure for Gauss-Bonnet and Lovelock gravities. It is shown that by employing the general expression for temperature Th =｜κ｜/2π= 1/2πτA （1-τA/2HτA） associated with the apparent horizon of a Friedman Robertson-Walker （FRW） universe and assuming Tm = bTh, we are able to construct conditions for which the generalized second law holds in Gauss Bonnet and Lovelock gravities, where Tm and Th are the temperatures of the source and the horizon respectively.     

Generalized uncertainty principle and black hole entropy

Recently, there has been much attention devoted to resolving the quantum corrections to the Bekenstein–Hawking black hole entropy. In particular, many researchers have expressed a vested interest in the coefficient of the logarithmic term of the black hole entropy correction term. In this Letter, we calculate the correction value of the black hole entropy by utilizing the generalized uncertainty principle and obtain the correction terms of entropy, temperature and energy caused by the generalized uncertainty principle. We calculate Cardy–Verlinde formula after considering the correction. In our calculation, we only think that the Bekenstein–Hawking area theorem is still valid after considering the generalized uncertainty principle and do not introduce any assumption. In the whole process, the physics idea is clear and calculation is simple. It offers a new way for studying the corrections caused by the generalized uncertainty principle to the black hole thermodynamic quantity of the complicated spacetime.     

Canonical Entropy and Phase Transition of Rotating Black Hole

Recently, the Hawking radiation of a black hole has been studied using the tunnel effect method. The radiation spectrum of a black hole is derived. By discussing the correction to spectrum of the rotating black hole, we obtain the canonical entropy. The derived canonical entropy is equal to the sum of Bekenstein-Havcking entropy and correction term. The correction term near the critical point is different from the one near others. This difference plays an important role in studying the phase transition of the black hole. The black hole thermal capacity diverges at the critical point. However, the canonical entropy is not a complex number at this point. Thus we think that the phase transition created by this critical point is the second order phase transition. The discussed black hole is a five-dimensional Kerr-AdS black hole. We provide a basis for discussing thermodynamic properties of a higher-dimensional rotating black hole.     

Viscous Cosmology and Thermodynamics of Apparent Horizon

It is shown that the differential form of Friedmann equations of Friedman--Robertson--Walker (FRW) universe can be recast as a similar form of the first law T_hdS_h = dE + WdV of thermodynamics at the apparent horizon of FRW universe filled with the viscous fluid. It is also shown that by employing the general expression of temperature associated with the apparent horizon of an FRW universe and assumed that the temperature T_m of the energy inside the apparent horizon is proportional to the horizon temperature T_m= bT_h, we are able to show that the generalized second law of thermodynamics holds in the Einstein gravity provided T_h-T_m/r^~_A ≤(ρ+P^~).     

Constraints on Slim Accretion Discs

We show that when the gravitational force in the vertical direction is correctly calculated, the well-known S- shaped sequence of thermal equilibrium solutions can be constructed only for small radii of black hole accretion flows, such that slim accretion discs can possibly exist only in the inner regions of these flows.     

Saturation and condensate fraction reduction of cold alpha matter

The ground state energy of ideal α  -matter at T=0$T=0$ is analyzed within the framework of variational theory of Bose quantum liquids. Calculations are done for three local α–α potentials with positive volume integrals and two-body correlation functions obtained from the Pandharipande–Bethe equation. The energy per particle of α matter is evaluated in the cluster expansion formalism up to four-body diagrams, and using the HNC/0 and HNC/4 approximation for a Bose liquid. At low densities the two methods predict similar EOS whereas at higher densities they are sensitively different, the HNC approximation providing saturation at lower density, bellow the saturation value of nuclear matter. Inclusion of higher-order terms in the cluster expansion of the condensate fraction is leading to a stronger depletion of the alpha condensate with the density compared to the two-body approximation prediction.     

Sagnac Effect in the Kerr-Newman and Reissner-Nordstrom Fields

By means of a formal analogy with the Aharonov-Bohm effect, the Sagnac time delay and the corresponding Sagnac phase shift in the Kerr-Newman and Reissner-Nordstrfm spacetimes are discussed. We find that the effect depends on the properties of the source of the gravitational field. The contributions made by the electric charge of the gravitational source can be employed to weaken it in the Kerr-Newman spacetime, even if a phase shift and a time delay still appear. This is due to the properties of the rotating source of the gravitational field.     

Quasinormal Spectrum and Quantization of the Kerr--Newman Black Hole

The intermediate asymptotic quasinormal mode spectrum of the charged scalar and Dirac fields in the near extremal Kerr-Newman black hole is studied analytically, It is found that the quasinormal mode spectrum can be expressed in terms of the Hawking temperature Thb, the electric potential Ф＋ and the horizon＇s angular velocity ΩH for the case of （eФ_ ＋ mΩH） 〉 （1 - 4πThb）Re（ω） （where e is the charge and m is the azimuthal projection number）, whereas it is only relevant to the charge and the mass parameter for another case. It is also shown that by using the Bohr＇s correspondence principle, the fundamental change in the black-hole surface area induced by the emission of a rotating charged quantum from the Kerr-Newman black hole is in accord with the Bekenstein-Mukhanov general prediction.     

A realistic model of superfluidity in the neutron star inner crust

A semi-microscopic self-consistent quantum approach developed recently to describe the inner-crust structure of neutron stars within the Wigner-Seitz (WS) method with the explicit inclusion of neutron and proton pairing correlations is further developed. In this approach, the generalized energy functional is used which contains the anomalous term describing the pairing. It is constructed by matching the realistic phenomenological functional by Fayans et al. for describing the nuclear-type cluster in the center of the WS cell with the one calculated microscopically for neutron matter. Previously, the anomalous part of the latter was calculated within the BCS approximation. In this work corrections to the BCS theory which are known from the many-body theory of pairing in neutron matter are included into the energy functional in an approximate way. These modifications have a sizable influence on the equilibrium configuration of the inner crust, i.e. on the proton charge Z and the radius R _c of the WS cell. The effects are quite significant in the region where the neutron pairing gap is larger.     

Neutron stars with isovector scalar correlations

Neutron stars with the isovector scalar δ-field are studied in the framework of the relativistic mean-field (RMF) approach in a pure-nucleon-plus-lepton scheme. The δ-field leads to a larger repulsion in dense neutron-rich matter and to a definite splitting of proton and neutron effective masses. Both features are influencing the stability conditions of the neutron stars. Two parametrizations for the effective nonlinear Lagrangian density are used to calculate the nuclear equation of state (EOS) and the neutron star properties, and compared to correlated Dirac-Brueckner results. We conclude that in order to reproduce reasonable nuclear structure and neutron star properties within a RMF approach, a density dependence of the coupling constants is required.     

Berry phase and quantum criticality in Yang-Baxter systems

Spin interaction Hamiltonians are obtained from the unitary Yang-Baxter -matrix. Based on which, we study Berry phase and quantum criticality in the Yang-Baxter systems.     

The influence of free quintessence on gravitational frequency shift and deflection of light with 4D momentum

On the basis of the 4D momentum, the influence of quintessence on the gravitational frequency shift and the deflection of light are examined in modified Schwarzschild space. We find that the frequency of a photon depends on the state parameter of the quintessence w _q: the frequency increases for −1<w _q<−1/3 and decreases for −1/3<w _q<0. Meanwhile, we adopt an integral power number a (a=3ω _q+2) to solve the orbital equation of photon. The photon’s potentials become higher with the decrease of ω _q. The behavior of the bending light sensitively depends on the state parameter ω _q. In particular, for the case of ω _q=−1, there is no influence on the deflection of light by quintessence. Furthermore, according to the H-masers of the GP-A redshift experiment and long-baseline interferometry, the constraints on the quintessence field in the solar system are presented here.     

Pairwise Entanglement and Quantum Phase Transitions in Spin Systems

We examine several well-known quantum spin models and categorize the behaviour of pairwise entanglement at quantum phase transitions. A unitied picture on the connection between the entanglement and quantum phase transition in spin systems is presented.     

Influence of water states in hydrogels on the transmissibility and permeability of oxygen in contact lens materials

The properties of water in soft contact lenses such as the water content, free-to-bound water ratio were key determinants of their oxygen transmissibility characteristics. Differential scanning calorimetry (DSC) was used for measuring the different states of water in hydrogel materials. The convenient apparatus was devised for testing the oxygen permeability coefficient of hydrogel membranes. DSC data showed that the content of freezing water in hydrogel increased with growth of N-vinyl pyrrolidone (NVP) percentage, and the non-freezing water in hydrogel increased with growth of 2-hydroxyethylmethacrylate (HEMA) percentages. It was found that the transmissibility and permeability of oxygen in hydrogel could be described according to the solution-diffusion model. The systematic variations in chemical structure and volume fraction of water in polymer bring about significant changes in oxygen permeability coefficients. The permeability of the material was affected by the freezing water in hydrogel rather than by the non-freezing water.     

Isothermal adsorption kinetics on heterogeneous surfaces

Adsorption kinetics on energetically heterogeneous surfaces under isothermal conditions is analyzed using the uniform energy distribution model. Considering the quasi-equilibrium of surface diffusion between the adsorption sites with different energy, the kinetic equations dΘ/dt=(k_ap−A_dK_diff)(1−Θ) for first-order adsorption and dΘ/dt=k_ap(1−Θ)²−A_dK_diffΘ(1−Θ) for dissociative adsorption are obtained, where K_diff is a coefficient describing the surface diffusion equilibrium, which depends on the coverage and the energy distribution. Under isochoric conditions with p decreasing due to adsorption, surface diffusion accelerates the rate towards equilibrium significantly, as observed in static calorimetric adsorption experiments. An approximate solution in Lagergren form is derived for this condition.