标题： QED中的有效弦$_3$ 显示英文标题

标题： Effective Strings in QED$_3$

摘要： 有效弦理论描述了像杨-米尔斯理论这样具有禁闭弦的物理现象，在这些理论中，质量间隙 $M_{gap}^2$ 与弦张力 $T$ 同阶。 在 $2+1$ 维度下，有一类禁闭理论，包括由波利亚科夫最早分析的有质量的QED $_3$，对于这些理论 $M_{gap}^2\ll T$ 成立。 这些理论在大约 $M_{gap}$ 的低能下是弱耦合的，可以进行微扰分析。 本文中，我们分析了这类理论中弦的物理性质，重点关注能量约为$M_{gap}$（但仍远低于$\sqrt{T}$）时的 QED$_3$。 我们论证了在这种理论中的弦宽应该与长度无关，且为$1/M_{gap}$数量级，只要弦不是指数级长。 我们还以微扰论的最低阶计算了在圆周上约束弦的基态能量以及 Nambu-Goldstone玻色子在弦世界面上的散射。 显示英文摘要

摘要： Effective string theory describes the physics of long confining strings in theories, like Yang-Mills theory, where the mass gap $M_{gap}^2$ is of the same order as the string tension $T$. In $2+1$ dimensions, there is a class of confining theories, including massive QED$_3$ as first analyzed by Polyakov, for which $M_{gap}^2\ll T$. These theories are weakly coupled at low energies of order $M_{gap}$, and may be analyzed perturbatively. In this paper, we analyze the physics of strings in such theories, focusing on QED$_3$, at energies of order $M_{gap}$ (but still well below $\sqrt{T}$). We argue that the width of the string in these theories should be of order $1/M_{gap}$ independently of its length, as long as the string is not exponentially long. We also compute at leading order in perturbation theory the ground state energy of a confining string on a circle, and the scattering of Nambu-Goldstone bosons on the string worldsheet.