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The lattice QCD finite temperature SU (3) glueball spectrum and the QCD phase transition , and the SD phase transition in the excitation spectrum of the nature and shape of the shell model of nuclear low

Author: MengXiangFei
Tutor: LiuYuBin
School: Nankai University
Course: Theoretical Physics
Keywords: Lattice gauge QCD Rubber Ball QCD phase transition Canonical ensemble WNEM SD -pair shell model Electromagnetic transitions Critical
CLC: O572.243
Type: PhD thesis
Year: 2009
Downloads: 81
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Abstract

The main content of the paper contains a lattice quantum chromodynamics (QCD) (Lattice QCD) and the nucleus pair shell model (SDPSM) two areas. Finite density QCD at finite temperature QCD phase transition, due to relativistic heavy ion collisions (RHIC) and the close relationship of cosmic particle physics experiment, has become an important field of research. However, in the QCD phase transition region (T ∈ [100,300] MeV), the quark-gluon are strongly coupled system, the traditional perturbation theory can not be applied. And the first principle lattice QCD theory can give reliable results. Lattice QCD, here we mainly discuss two QCD phase transition and quark-gluon plasma (QGP) is closely related to nature. First, the use of the anisotropic lattice temperature range 0.3T _c 1.9T _c quenched SU (3) the thermodynamic properties of the rubber ball. In order to make the rubber ball operator projection of the ground state, we use a combination of smearing program variational method has been optimized to the operator. The thermal correlation function of the grid points defined on all 20 channels. Given in the display of all the results of the slopes, from low to Approaching critical temperature T _c process, the gum ball the Pole-massM _G is almost constant, exceeds a critical temperature, began to dissolve. Pole-mass thermal width Gamma by setting each ball of hot glue ground state, we use the Breit-Wigner ansatz 0 ^{0 ^{- and 2 ^{Road correlation function. The analysis showed that ω ₀ in the entire temperature region of the study, no significant temperature response, the heat width the gamma in critical temperature T _c upper and lower significant difference. The thermal width value in T _C under very small (only ω ₀ of a few percent or even smaller), but when the T> the T _c, he was a sharp increase in the T ≈ the 1.9T _c almost the gamma ~ omega / 2. Furthermore, in the study of finite density QCD expects to the QCD phase change the critical point there is a phase transition from a low density of cross-over to a finite density of order. In order to study the finite density QCD phase diagram, we apply the regular ensemble method to scan the temperature - density space. For a given temperature, we profiled chemical potential corresponding baryon number density function form and find a signal corresponding to a first-order phase transition of the S-Shape \Wilson Fermi conduct research, including lattice ^{3 × 4, pi-meson mass m _pi ≈ 1 GeV. As a check, we have embarked on the 4-Flavor simulation results gives a clear signal. The case of 2-flavor of until 0.83T _c we still see less than a first-order phase transition corresponding to the signal. Here, we also developed Winding Number Expansion Method. The nucleon pair shell model, is based on the SD subspace truncate build. First, we apply SDPSM to the ^{126-134 Xe and ^{128-136 Ba. We know that these nuclear demonstrate O (6) symmetry. Here, we use a Hamiltonian contains only three parameters to describe the nature of the nuclear spectrum and electromagnetic transitions. Theoretical and experimental results were in good agreement, M1 strength split with the increase in the number of neutrons naturally occurring. At the same time, the results show that with the increase in the number of nuclear, SD approximation performance is getting better. On the other hand, we also used the SDPSM to study the proton - neutron coupling system in the shape of the phase transition. The obtained results show that the phase transition behavior of the SDPSM interacting boson model U (5)-SU (3), U (5)-SO (6) becomes a critical point symmetry consistent performance.}}}}}}

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