TOPOLOGICAL ASPECTS OF THE PROTON VORTEX CLUSTERS IN THE CORE OF A NEUTRON STAR

2009 ◽  
Vol 18 (12) ◽  
pp. 1839-1849
Author(s):  
JUN LIANG ◽  
YISHI DUAN
Keyword(s):  
Neutron Star ◽  
Topological Structure ◽  
Order Parameter ◽  
Current Theory ◽  
Bifurcation Points ◽  
The Core ◽  
Topological Current ◽  
London Equation ◽  
Zero Points ◽  
Topological Charges

Based on the ϕ mapping topological current theory, the proton vortex clusters in the core of a neutron star are investigated. We derive rigorously the London equation with topological structure for superconducting protons. We also show that the proton vortices can only stem from the zero points of the vector order parameter. The evolution of the proton vortices is discussed, the proton vortices are found generating or annihilating at the limit points and splitting or merging at the bifurcation points of the vector order parameter, and the total topological charges remain invariant during the evolution.

ϕ-MAPPING TOPOLOGICAL THEORY IN TWO-GAP SUPERCONDUCTOR

2004 ◽  
Vol 18 (09) ◽  
pp. 1309-1318 ◽  
Author(s):  
YISHI DUAN ◽  
XUGUANG SHI
Keyword(s):  
Magnetic Field ◽  
Topological Structure ◽  
Topological Theory ◽  
Topological Current ◽  
Composite Vortex ◽  
Mapping Theory ◽  
The Magnetic Field ◽  
Zero Points

In this paper, the topological structure of the two-gap superconductor is discussed in detail based on the ϕ-mapping theory. The expression of the vorticity ∇×V of the composite vortex is given and the relation between the vorticity and the magnetic field which is carried by the composite vortex is discussed. The curl of velocity ∇×V has important relation to δ2(ϕ) or we can say that ∇×V has an important relation to the zero points of ϕ. The inner structure of the topological current is characterized by the ϕ-mapping topological numbers Hopf-index and Brouwer degrees.

0 + 1-DIMENSIONAL TQFT: FROM HILBERT VECTOR SPACE TO TANGLE CATEGORY

2013 ◽  
Vol 10 (03) ◽  
pp. 1250087
Author(s):  
XU-GUANG SHI
Keyword(s):  
Field Theory ◽  
Quantum Field Theory ◽  
Vector Space ◽  
Current Theory ◽  
Topological Quantum Field Theory ◽  
Quantum Field ◽  
Topological Quantum ◽  
Topological Current ◽  
Zero Points

In general, topological quantum field theory (TQFT) is studied in detail from the n-dimensional cobordism (nCob) to the Hilbert vector space. However, we study the TQFT in the different way in this paper, that is, the TQFT is studied from the Hilbert vector space to nCob. To do this, the theory called the ϕ-mapping topological current theory is used. The relation between the objects and zero points of the Hilbert states in the Hilbert vector space is studied in this frame. The relation between the morphism and topological current is revealed too.

TOPOLOGICAL STRUCTURE AND EVOLUTION OF SPACE–TIME DISLOCATIONS AND DISCLINATIONS

2007 ◽  
Vol 22 (07) ◽  
pp. 1335-1351 ◽  
Author(s):  
Y. S. DUAN ◽  
L. ZHAO
Keyword(s):  
Topological Structure ◽  
Order Parameter ◽  
Space Time ◽  
Gauge Potential ◽  
Topological Properties ◽  
Decomposition Theory ◽  
Bifurcation Points ◽  
Parameter Field ◽  
Limit Points ◽  
Mapping Theory

By making use of the gauge potential decomposition theory and ϕ-mapping theory, the topological structure and the topological quantization of dislocations and disclinations are studied in the framework of Riemann–Cartan space–time manifold. The evolution of dislocation strings and disclination points is also studied from the topological properties of the order parameter field. The dislocations and disclinations are found generating or annihilating at the limit points and encountering, splitting, or merging at the bifurcation points of the order parameter field.

TOPOLOGICAL OBJECTS IN THE O(3) NONLINEAR SIGMA MODEL

2007 ◽  
Vol 22 (31) ◽  
pp. 2379-2386
Author(s):  
PENG-MING ZHANG ◽  
XI-GUO LEE ◽  
SHAO-FENG WU ◽  
YI-SHI DUAN
Keyword(s):  
Sigma Model ◽  
Topological Defects ◽  
Current Theory ◽  
Gauge Potential ◽  
Nonlinear Sigma Model ◽  
Dimensional Model ◽  
Vortex Lines ◽  
Dimensional Spacetime ◽  
Topological Current ◽  
Topological Charges

We study the topological defects in the nonlinear O(3) sigma model in terms of the decomposition of U(1) gauge potential. Time-dependent baby skyrmions are discussed in the (2+1)-dimensional spacetime with the CP1 field. Furthermore, we show that there are three kinds of topological defects–vortex lines, point defects and knot exist in the (3+1)-dimensional model, and their topological charges, locations and motions are determined by the ϕ-mapping topological current theory.

TOPOLOGICAL STRUCTURE OF VORTEX LINES OF QUANTUM ELECTRON PLASMAS IN THREE-DIMENSIONAL SPACE

2009 ◽  
Vol 23 (11) ◽  
pp. 2439-2447
Author(s):  
XUGUANG SHI ◽  
YISHI DUAN
Keyword(s):  
Dimensional Space ◽  
Three Dimensional ◽  
Current Theory ◽  
Brouwer Degree ◽  
Electron Plasmas ◽  
The Core ◽  
Vortex Lines ◽  
Quantum Electron ◽  
Topological Current ◽  
Three Dimensional Space

The topological properties of quantum electron plasmas in three-dimensional space are presented. Starting from ϕ-mapping topological current theory, the vortex lines are just at the core of wave function obtained. It is shown that the vorticity of the vortex can be expressed by the Hopf index and the Brouwer degree. We find that the vortex lines are unstable in some conditions and the evolution of vortex lines at the bifurcation points is given.

A NOVEL THEORY OF ELECTROWEAK INSTANTONS

2005 ◽  
Vol 20 (37) ◽  
pp. 2891-2902
Author(s):  
TIEYAN SI ◽  
YI-SHI DUAN
Keyword(s):  
Topological Structure ◽  
Higgs Field ◽  
Current Theory ◽  
Exact Expression ◽  
Novel Approach ◽  
Topological Current ◽  
Novel Theory ◽  
Instanton Number ◽  
Expansion Theory ◽  
Symmetric Phase

Using ϕ-mapping topological current theory and the expansion theory of the δ-function, we found a more exact expression of conventional instanton and multi-instanton. We established a novel approach to instanton. It is found that the instantons arise from the symmetric phase of the Higgs field ϕ=0, the fine topological structure of the instanton number is also given.

scholarly journals Neutron star properties and the equation of state for the core

2017 ◽  
Vol 599 ◽  
pp. A119 ◽  
Author(s):  
J. L. Zdunik ◽  
M. Fortin ◽  
P. Haensel
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
The Core

scholarly journals Nuclear equation of state and neutron star cooling

2017 ◽  
Vol 26 (04) ◽  
pp. 1750015 ◽  
Author(s):  
Yeunhwan Lim ◽  
Chang Ho Hyun ◽  
Chang-Hwan Lee
Keyword(s):  
Neutron Star ◽  
Equation Of State ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Thermal Evolution ◽  
Observation Data ◽  
Nuclear Equation Of State ◽  
The Core ◽  
Dense Nuclear Matter ◽  
Nuclear Models

In this paper, we investigate the cooling of neutron stars with relativistic and nonrelativistic models of dense nuclear matter. We focus on the effects of uncertainties originated from the nuclear models, the composition of elements in the envelope region, and the formation of superfluidity in the core and the crust of neutron stars. Discovery of [Formula: see text] neutron stars PSR J1614−2230 and PSR J0343[Formula: see text]0432 has triggered the revival of stiff nuclear equation of state at high densities. In the meantime, observation of a neutron star in Cassiopeia A for more than 10 years has provided us with very accurate data for the thermal evolution of neutron stars. Both mass and temperature of neutron stars depend critically on the equation of state of nuclear matter, so we first search for nuclear models that satisfy the constraints from mass and temperature simultaneously within a reasonable range. With selected models, we explore the effects of element composition in the envelope region, and the existence of superfluidity in the core and the crust of neutron stars. Due to uncertainty in the composition of particles in the envelope region, we obtain a range of cooling curves that can cover substantial region of observation data.

scholarly journals Non-spherical nucleon clusters in the mantle of a neutron star: CLDM based on Skyrme-type forces

2021 ◽  
Vol 2103 (1) ◽  
pp. 012004
Author(s):  
N A Zemlyakov ◽  
A I Chugunov ◽  
N N Shchechilin
Keyword(s):  
Neutron Star ◽  
Nuclear Matter ◽  
Liquid Drop ◽  
Outer Region ◽  
Spherical Shape ◽  
Baryon Number ◽  
Compressible Liquid ◽  
Liquid Drop Model ◽  
The Core ◽  
Nuclear Clusters

Abstract Neutron stars are superdense compact astrophysical objects. The central region of the neuron star (the core) consists of locally homogeneous nuclear matter, while in the outer region (the crust) nucleons are clustered. In the outer crust these nuclear clusters represent neutron-rich atomic nuclei and all nucleons are bound within them. Whereas in the inner crust some neutrons are unbound, but nuclear clusters still keeps generally spherical shape. Here we consider the region between the crust and the core of the star, so-called mantle, where non-spherical nuclear clusters may exist. We apply compressible liquid drop model to calculate the energy density for several shape types of nuclear clusters. It allows us to identify the most energetically favorable configuration as function of baryon number density. Employing four Skyrme-type forces (SLy4 and BSk24, BSk25, BSk26), which are widely used in the neutron star physics, we faced with strong model dependence of the ground state composition. In particular, in agreement with previous works within liquid drop model, mantle is absent for SLy4 (nuclear spheres directly transit into homogeneous nuclear matter; exotic nuclear shapes do not appear).

Ecological approaches to perceptual learning: learning to perceive and perceiving as learning

2019 ◽  
Vol 27 (6) ◽  
pp. 363-388 ◽  
Author(s):  
Agnes Szokolszky ◽  
Catherine Read ◽  
Zsolt Palatinus ◽  
Kinga Palatinus
Keyword(s):  
Language Development ◽  
Perceptual Learning ◽  
Tool Use ◽  
Evolutionary Biology ◽  
Ecological Psychology ◽  
Current Theory ◽  
Review Article ◽  
The Core ◽  
Core Concepts ◽  
Development And Evolution

In this theoretical review article, our primary goal is to contribute to the post-cognitivist understanding of learning to perceive and perceiving as learning, by discussing a framework for perception and perceptual learning initiated by James J Gibson, and extended by Eleanor J Gibson and others. This Ecological Psychology has a coherent set of assumptions based on the concept of mutualism between the perceiving organism and its surroundings, and the idea of affordances as action possibilities of the surround that are perceptible by the organism. At the same time, Ecological Psychology, broadly construed, consists of different perspectives that take different routes to address questions related to the core concepts of perceptual learning. In this article, we focus on three theoretical stances within Ecological Psychology on the issue of perceptual learning: that of Eleanor J Gibson, the current theory of direct learning by Jacobs and Michaels, and the “organicist” approach based on ideas of organicist biology and developments in evolutionary biology. We consider perceptual learning as embedded in development and evolution, and we explore perceptual learning in more depth in the context of tool use and language development. We also discuss the relation between Ecological Psychology and Enactivism on the nature of perception. In conclusion, we summarize the benefits of Ecological Psychology, as a robust but still developing post-cognitivist framework, for the study of perceptual learning and cognitive science in general.

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