The Study On Dynamics Of High Density Nuclear Matter And Observational Constraints On Theory Of Neutron Stars

Neutron star is a sort of compact stars,which is the final product in the evolution of stellar.Since the idea of neutron star was proposed and then the concept that pulsars are rotating neutron stars was accepted,the components and properties of dense matter in neutron stars have attracted much attention.But up to now,the fundamental problem of the equation of state in the core is still the main mystery of neutron stars,we could test it by the observation,which has become one of the leading issues of the research about neutron stars.The interiors of neutron stars contain matter under extreme physical conditions.This provides an environment for numerous subatomic particles to compete with each other. After a particular description of the equations of state about all sorts of models,we find that the appearance of exotic particles softens the equation of state.The differences between them lead to different stellar structures,mass-radius relations and the maximum masses,which would provide us an opportunity to constrain the equations of state for neutron-star matter by comparing with the observational quantities such as mass and redshift. Meanwhile,we consider and predict the existence of overcompressed metastable state of the real phase transition in the interior of neutron stars,and obtain the description about it through calculation.This provides us with a conceivable method to study the mechanism about the release of latent heat in the process of the deconfinement phase transition,and also be helpful for estimating the thermal evolution of compact stars.The gravitational wave especial the r-mode instability plays an important role in the limit rotation of compact stars.The differences between the dynamics of dense matter would damp the instability distinctly,which may cause diverse behaviors of the limit rotation. After a detailed analysis of all the possible kinetic courses in the neutron stars, we find that it is the non-leptonic course with nonconservation of the strangeness number that contributes most to the bulk viscosity.We calculate the bulk viscosity of nucleon- hyperon-quark mixed matter,and evaluate the contribution of the sharp interface in hybrid star to the viscous damping.These are the positive complementarities for the former research.By contrast,we find that different models have different critical rotation frequencies and diverse rotational evolution behaviors,which may also provide us a method to constrain the models of neutron stars.We discuss the observational masses,redshifts and rotation frequencies constraints on the equations of state in the cores of neutron stars.We discover that it is hard for us to distinguish different neutron star models by the simple constraints of masses,redshifts and rotations on mass-radius relations.We adopt a new train of thought to constrain the equations of state of neutron stars.It is possible for us to probe the compositions and equations of state in the cores of neutron stars combined with the observational rotation constraints on mass(radius)-Kepler rotation and mass(radius)-r-mode limit rotation relations besides the observational mass constraints on mass-radius relations.We carefully analyse two samples SAX J1808.4-3658 and XTE J1739-285.We believe that the core of the millisecond pulsar SAX J1808.4-3658 should have nuclear matter with strangeness number and the possible submillisecond pulsar XTE J1739-285 may have strange quark matter inside.