In High Energy Physics, Thermodynamics And Statistical Physics And Cosmology

Thermodynamics and statistical physics are very important theoretical tools in studying the macroscopic properties of system consisting of many objects. This thesis is devoted to the related application of this important branch of the theoretical physics in the fields of the high energy physics and general relativity, such as, the thermodynamic consistency of quasiparticle system with effective mass, the liquid-gas phase transition of strange hadronic matter with weak hyperon-hyperon interaction, slowly rotating neu-tron stars and hadronic stars in the chiral SU(3) quark mean field model, temperature effect on the power spectrum in inflation, energy and entropy radiated by a black hole embedded in a higher dimensional de Sitter braneworld, stability of warped black string with nontrivial topology in 5 dimensional Anti-de Sitter spacetime, etc. We will see that the important thermodynamic concepts, such as temperature, statistics, entropy, have very important applications in many fields of physics.The main conclusions of this thesis are as follows:1. By introducing the effective mass as a new independent variable in the description of the thermodynamic reversible process, we have successfully solved the thermo-dynamic consistency problem of quasiparticle system with effective mass. Via two concrete models as examples, our treatment is applicable to different quasiparticle systems. Compared with the old treatments, our results are more consistent with theoretical predictions or lattice data. Besides, the introduction of effective mass as a new independent variable makes it possible to modify the pressure and en-tropy by an arbitrary function of the effective mass, which results in the expected instability of negative pressure naturally and self-consistently.2. With the result of weak Y-Y interaction reported in the recent experiment, we reexamined the liquid-gas phase transition of the strange hadronic matter, and find that, with the weak interaction, the system becomes more unstable and the phase transition can happen more easily.3. In order to examine the upper limit of the maximum mass of compact stars, we consider the correction to the stellar structure from slow rotation. We find the rotation can increase the maximum mass significantly, but the maximum mass of the strange hadronic star in the chiral SU(3) quark mean-field model is still too small to explain the massive pulsar observed, because the equation of state of the strange hadronic matter is too soft.4. By taking the thermal vacuum of the inflaton field to include the finite temper-ature effect, we obtain the finite temperature correction to the spectrum by the thermal field dynamics. After fitting with the cosmic microwave background radi-ation spectrum, we find that the modified spectrum can explain the observational data better.5. After completely examine the different modes of the radiation of energy and entropy of the black hole in higher dimensional de-Sitter spacetime, we find the entropy lost by the black hole and obtained in the radiation are always of the same order in the radiation process, which is in favor of the Bekenstein's conjecture about black hole entropy.6. By the study of the gravitational tensor perturbation of the warped black string in 5 dimensional anti-de-Sitter spacetime, we find that the instability exists in different topologies and radii, depending on the mode of the perturbation in the 5th dimension. This condition for instability challenges the relation between the dynamic instability and thermodynamic instability.7. Besides, we also studied the transition of effective equation of state of dark energy in the Dvali-Gabadadze-Porrati braneworld model with bulk content. Our numerical results show that the introduction of bulk content can realize the transition of the effective equation of state of dark energy within this model, where the bulk matter, rather than the energy flow between the bulk and brane, plays the key role.