标题： 稀疏子在多临界3+epsilon维宇称破坏场论中的行为 显示英文标题

标题： Dilaton in a Multicritical 3+epsilon-D Parity Violating Field Theory

摘要： 大约尺度和共形不变量子场论的多临界行为，可以视为在3+epsilon维度中通过一个几乎边缘的宇称破坏算符对临界Gross-Neveu模型的扰动，使用大$N$展开进行研究。 当epsilon大于1/N量级的数时，该扰动是边缘相关的，并且发现它表现出近似尺度对称性的自发破缺，同时在其谱中出现了一个轻标量。 标量质量是参数上很小的，为epsilon乘以费米子质量，它可以被识别为一个轻的标度子。 当维度降低到3时，Gross-Neveu模型的扰动变为边缘无关的，势能的最小值变成最大值，理论具有非微扰全局不稳定性。 存在一个亚稳的微扰相，在其中标量不凝聚，费米子是无质量的，与一个能量上更优的相之间有一个能量壁垒，其高度为1（而不是N），该相具有逃逸凝聚。 显示英文摘要

摘要： The multi-critical behaviour of an approximately scale and conformal invariant quantum field theory, which can be regarded as the deformation of the critical Gross-Neveu model in 3+epsilon dimensions by a nearly marginal parity violating operator, is studied using a large $N$ expansion. When epsilon is greater than a number of order 1/N, the deformation is marginally relevant and it is found to exhibit spontaneous breaking of the approximate scale symmetry accompanied by the appearance of a light scalar in its spectrum. The scalar mass is parametrically small, of order epsilon times the fermion mass and it can be identified with a light dilaton. When the dimension is reduced to 3 the deformation of the Gross-Neveu model becomes marginally irrelevant, what was a minimum of the potential becomes a maximum and the theory has a non-perturbative global instability. There is a metastable perturbative phase where the scalar does not condense and the fermions are massless separated by an energy barrier with height of order one (rather than N) from an energetically favoured phase with a runaway condensate.