1990 Fiscal Year Final Research Report Summary
Quantum Chromodynamics by Uumerical Method
| Project/Area Number |
01460017
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
核・宇宙線・素粒子
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| Research Institution | Kyoto University |
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Principal Investigator |
FUKUGITA M. Kyoto University, Yukawa Institute, Associate Professor, 基礎物理學研究所, 助教授 (40100820)
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| Co-Investigator(Kenkyū-buntansha) |
UKAWA A. University of Tsukuba, Institute of Physics, Professor, 物理学系, 教授 (10143538)
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| Project Period (FY) |
1989 – 1990
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| Keywords | lattice gauge theory / quantum chromodynamics / quark-hadron transition / finite-size scaling / large-scale numerical simulation / 三次元三次態ポッツ模型 / カイラル相轉移 |
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| Research Abstract |
Fundamental problems of lattice QCD is studied by numerical methods. The main results are :
(1) The deconfining phase transition of pure SU (3) gauge theory was shown to be first order in all aspects. This settled the issue questioned by an Italian group about the order of the deconfining phase transition that it might be second order. The importance of the study of finite-size scaling was emphasized.
(2) The order of the chiral phase transition for the system with dynamical quarks was studied with the method of finite-size scaling. The system with quark flavor number N_f=4 was shown to have a strong first-order phase transition. However, we could not obtain decisive answer for the N_f=2 case. Afterwards, the Columbia group made a simulation for the latter case on a larger lattice. Combining their result with ours and applying finite size scaling, it is concluded that the N_f=2 system has no phase transition.
(3) Finite-lattice effects are studied for hadron mass calculations in the case of full QCD. It was shown that a simulation on a fairly large lattice (e. g., beta=5.7 on 16^4), which is supposed to be free from such effects, still suffers significantly from the finite-size effect. This means that a proper procedure should be taken to remove this effect in order to obtain correct physical masses.
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