Unsal Mithat
SLAC and Department of Physics, Stanford University, Stanford, CA 94025, USA.
Phys Rev Lett. 2008 Jan 25;100(3):032005. doi: 10.1103/PhysRevLett.100.032005. Epub 2008 Jan 24.
We analyze the vacuum structure of SU(2) QCD with multiple massless adjoint representation fermions formulated on a small spatial S(1) x R(3). The absence of thermal fluctuations, and the fact that quantum fluctuations favor the vacuum with unbroken center symmetry in a weakly coupled regime, renders the interesting dynamics of these theories analytically calculable. Confinement and the generation of the mass gap in the gluonic sector are shown analytically. In this regime, theory exhibits confinement without continuous chiral-symmetry breaking. However, a flavor singlet chiral condensate (which breaks a discrete chiral symmetry) persists at arbitrarily small S(1). Under certain reasonable assumptions, we show that the theory exhibits a zero temperature chiral phase transition in the absence of any change in spatial center symmetry realizations.
我们分析了在小空间(S(1)×R(3))上构建的具有多个无质量伴随表示费米子的(SU(2))量子色动力学的真空结构。热涨落的不存在，以及在弱耦合 regime 中量子涨落有利于具有未破缺中心对称性的真空这一事实，使得这些理论的有趣动力学可以进行解析计算。在胶子 sector 中禁闭和质量间隙的产生通过解析得到展示。在这个 regime 中，理论表现出禁闭但没有连续手征对称性破缺。然而，一个味单态手征凝聚（它打破了一个离散手征对称性）在任意小的(S(1))下仍然存在。在某些合理假设下，我们表明该理论在空间中心对称性实现没有任何变化的情况下表现出零温度手征相变。
