Symmetry Breaking and Its Applications in Particle Physics

场论中的对称破缺是由某种不稳定性引起的。单粒子问题的不稳定性触发经典不稳定性。在经典稳定系统中，对称性有时会被量子不稳定性破坏。在这些情况下，不稳定性不会出现，除非我们检查束缚态谱。相对论束缚态问题由于必须对理论进行非扰动化而面临各种困难。然而，在渐近自由场论中，我们可以克服这些困难。当无质量夸克和反夸克之间的吸引力强到足以形成束缚态时，微扰真空变得不稳定，夸克获得质量。我们还研究了一些现象学的影响。

Symmetry breaking in field theory is caused by some instability. Instability in one-particle problem triggers classical instability. In classically stable systems, symmetry sometimes breaks down by quantum instability. In these cases, instability does not show up unless one examines bound state spectrum. Relativistic bound states problems have various difficulties since we have to renormalize the theory in non-purturbative way. In asymptotic free field theory, however, we can overcome these difficulties. When the attractive force between massless quark and anti-quark is strong enough to make a bound state, the perturbative vacuum becomes unstable and quark acquires mass. We also investigated some phenomenological implications.