4,870 research outputs found

    A new insight into neutrino energy loss by electron capture of iron group nuclei in magnetars surface

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    Based on the relativistic mean-field effective interactions theory, and Lai dong model \citep{b37, b38, b39}, we discuss the influences of superstrong magnetic fields (SMFs) on electron Fermi energy, nuclear blinding energy, and single-particle level structure in magnetars surface. By using the method of Shell-Model Monte Carlo (SMMC), and the Random Phase Approximation (RPA) theory, we detailed analyze the neutrino energy loss rates(NELRs) by electron capture (EC) for iron group nuclei in SMFs.Comment: 22 pages, 8 figures, accepted for publication in ApJS. arXiv admin note: text overlap with arXiv:astro-ph/0606674, arXiv:nucl-th/9707052, arXiv:nucl-th/9801012, arXiv:1505.07304 by other author

    Hidden symmetry and protection of Dirac points on the honeycomb lattice

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    The honeycomb lattice possesses a novel energy band structure, which is characterized by two distinct Dirac points in the Brillouin zone, dominating most of the physical properties of the honeycomb structure materials. However, up till now, the origin of the Dirac points is unclear yet. Here, we discover a hidden symmetry on the honeycomb lattice and prove that the existence of Dirac points is exactly protected by such hidden symmetry. Furthermore, the moving and merging of the Dirac points and a quantum phase transition, which have been theoretically predicted and experimentally observed on the honeycomb lattice, can also be perfectly explained by the parameter dependent evolution of the hidden symmetry.Comment: 5 pages, 2 figures, +6 pages of supplementary information. Welcome any comments

    Weyl semimetals in optical lattices: moving and merging of Weyl points, and hidden symmetry at Weyl points

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    We propose to realize Weyl semimetals in a cubic optical lattice. We find that there exist three distinct Weyl semimetal phases in the cubic optical lattice for different parameter ranges. One of them has two pairs of Weyl points and the other two have one pair of Weyl points in the Brillouin zone. For a slab geometry with (010) surfaces, the Fermi arcs connecting the projections of Weyl points with opposite topological charges on the surface Brillouin zone is presented. By adjusting the parameters, the Weyl points can move in the Brillouin zone. Interestingly, for two pairs of Weyl points, as one pair of them meet and annihilate, the originial two Fermi arcs coneect into one. As the remaining Weyl points annihilate further, the Fermi arc vanishes and a gap is opened. Furthermore, we find that there always exists a hidden symmetry at Weyl points, regardless of anywhere they located in the Brillouin zone. The hidden symmetry has an antiunitary operator with its square being −1-1.Comment: 10 pages, 5 figure

    A New Kind of Deformed Hermite Polynomials and Its Applications

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    A new kind of deformed calculus was introduced recently in studying of parabosonic coordinate representation. Based on this deformed calculus, a new deformation of Hermite polynomials is proposed, its some properties such as generating function, orthonormality, differential and integral representaions, and recursion relations are also discussed in this paper. As its applications, we calculate explicit forms of parabose squeezed number states, derive a particularly simple subset of minimum uncertainty states for parabose amplitude-squared squeezing, and discuss their basic squeezing behaviours.Comment: 18 pages, LaTe

    Graded Lie Algebra Generating of Parastatistical Algebraic Structure

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    A new kind of graded Lie algebra (we call it Z2,2Z_{2,2} graded Lie algebra) is introduced as a framework for formulating parasupersymmetric theories. By choosing suitable bose subspace of the Z2,2Z_{2,2} graded Lie algebra and using relevant generalized Jacobi identities, we generate the whole algebraic structure of parastatistics.Comment: 8 pages, LaTe

    Space Structure for the Simplest Parasupersymmetric System

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    Structure of the state-vector space for a system consisting of one mode parabose and one mode parafermi degree of freedom with the same parastatistics order pp is studied and a complete, orthonormal set of basis vectors in this space is constructed. There is an intrinsic double degeneracy for state vectors with mm parabosons and nn parafermions, where m≠0m \not= 0, n≠0n \not= 0, and n≠pn \not= p. It is also shown that the degeneracy plays a key role in realization of exact supersymmetry for such a system

    Topological semimetals with double-helix nodal link

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    Topological nodal line semimetals are characterized by the crossing of the conduction and valence bands along one or more closed loops in the Brillouin zone. Usually, these loops are either isolated or touch each other at some highly symmetric points. Here, we introduce a new kind of nodal line semimetal, that contains a pair of linked nodal loops. A concrete two-band model was constructed, which supports a pair of nodal lines with a double-helix structure, which can be further twisted into a Hopf link because of the periodicity of the Brillouin zone. The nodal lines are stabilized by the combined spatial inversion P\mathcal{P} and time reversal T\mathcal{T} symmetry; the individual P\mathcal{P} and T\mathcal{T} symmetries must be broken. The band exhibits nontrivial topology that each nodal loop carries a π\pi Berry flux. Surface flat bands emerge at the open boundary and are exactly encircled by the projection of the nodal lines on the surface Brillouin zone. The experimental implementation of our model using cold atoms in optical lattices is discussed.Comment: 10 pages, 7 figures. The title is changed, the main text and Supplemental Material are update

    Deformed Legendre Polynomial and Its Application

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    A new kind of deformed calculus was introduced recently in studying of parabosonic coordinate representation. Based on this deformed calculus, a new deformation of Legendre polynomials is proposed in this paper, some properties and applications of which are also discussed.Comment: 11 pages, LaTe

    Study of Magnetic Hysteresis Effects in a Storage Ring Using Precision Tune Measurement

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    With advances in accelerator science and technology in the recent decades, the accelerator community has focused on the development of next-generation light sources, for example the diffraction-limited storage rings (DLSRs), which requires precision control of the electron beam energy and betatron tunes. This work is aimed at understanding magnet hysteresis effects on the electron beam energy and lattice focusing in the circular accelerators, and developing new methods to gain better control of these effects. In this paper, we will report our recent experimental study of the magnetic hysteresis effects and their impacts on the Duke storage ring lattice using the transverse feedback based precision tune measurement system. The major magnet hysteresis effects associated with magnet normalization and lattice ramping are carefully studied to determine an effective procedure for lattice preparation while maintaining a high degree of reproducibility of lattice focusing. The local hysteresis effects are also studied by measuring the betatron tune shifts resulted from adjusting the setting of a quadrupole. A new technique has been developed to precisely recover the focusing strength of the quadrupole by returning it to a proper setting to overcome the local hysteresis effect

    Connecting neutron star observations to the high density equation of state of quasi-particle model

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    The observation of 1.97±0.041.97\pm0.04 solar-mass neutron-like star gives constraint on the equation of state (EOS) of cold, condensed matter. In this paper, the EOS for both pure quark star and hybrid star with a quark core described by quasi-particle model are considered. The parameters of quasi-particle model which affect the mass of both quark star and hybrid star can be constrained by the observation.Comment: 7 pages, 11 figure
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