Research for Nonperturbative Properties of Quarks, Gluons and Hadrons in Quantum Chromodynamics

基于量子色动力学（QCD）这一强相互作用的基本理论，我们在颜色约束、夸克多体系统、夸克-胶子-等离子体（QGP）、由超弦理论获得的全息QCD等方面进行了极具独创性的研究。我们对重子（如核子）的物理性质所引起的三夸克势进行了第一次精确的点阵量子动力学研究。我们澄清了三夸克势是用两体库仑和y型线性约束势的和来描述的。本研究被确立为一项重要工作，并被Rothe教授的教材《格点规范理论》引用。我们利用超弦理论中的规范/引力二象性，从对应于量子cd的d膜系统中获得重子作为手性孤子，首次在全息量子cd中进行了研究。我们首次对四夸克和五夸克等夸克多体系统中的约束势进行了详细的点阵- qcd研究，并发现弦图甚至在远距离上也适用于这些夸克多体系统。我们首次对晶格QCD中三夸克体系的胶子激发进行了详细的研究，发现胶子激发能约为1GeV，推测这是无胶子夸克模型成功的一个物理原因。我们研究了晶格QCD中的五夸克重子，并检查了边界条件的依赖性，结果表明在1.75 gev以下没有五夸克共振。我们研究了晶格QCD在有限温度下的调和态，并检查了边界条件的依赖性，发现即使在临界温度以上，即在QGP中，J/Psi仍然存在强子共振。7. 我们结合Schwinger-Dyson方程和晶格QCD结果，研究了有限温度/密度QCD。本文首次研究了晶格QCD中有限温度下夸克-胶子混合凝聚态。

Based on quantum chromodynamics (QCD), the fundamental theory of the strong interaction, we have performed highly original studies on color confinement, quark many-body systems, quark-gluon-plasma (QGP), holographic QCD obtained from the superstring theory, and so on.1. We perform in detail the first accurate lattice-QCD study of the three-quark potential, responsible to the physical properties of baryons such as nucleons. We clarify that the three-quark potential is described by the sum of two-body Coulomb and Y-type linear confinement potential. This study is established as an important work and is cited by Prof. Rothe's textbook "Lattice Gauge Theories".2. We perform the first study of baryons as chiral solitons in holographic QCD, which is obtained from the D-brane system corresponding to QCD using the gauge/gravity duality in the superstring theory.3. We perform in detail the first lattice-QCD study of the confinement potential in the quark many-body systems such as tetra-quarks and penta-quarks, and find that the string picture is applicable even for these quark many-body systems at large-distances.4. We perform in detail the first study of the gluonic excitation in three-quark systems in lattice QCD, and find a large gluonic excitation energy of about 1GeV, which is conjectured to lead to a physical reason of the success of the quark model without gluons.5. We study penta-quark baryons in lattice QCD with checking the boundary-condition dependence, and show that no penta-quark resonance appears below 1.75GeV.6. We study charmonia at finite temperature in lattice QCD with checking the boundary-condition dependence, and find that J/Psi survives as a hadronic resonance even above the critical temperature, i.e., in QGP. 7. We combine the Schwinger-Dyson equation and lattice QCD results, and investigate finite temperature/density QCD.8. We perform the first study of the quark-gluon mixed condensate at finite temperature in lattice QCD.