外场中的泛函重整化群：恒定场与恒定序参量
Functional renormalization group in an external field: constant field versus constant order parameter
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中文总结 AI 辅助
本文在泛函重整化群框架下，研究了外场边界条件（固定场或固定序参量）对φ^4理论流方程及伊辛临界标度的影响，并发现恒定应力下弹性耦合使部分不动点移入非物理参数区。
中文摘要 AI 辅助
对于受外场作用的系统，重整化群（RG）流既可以通过固定场来推导，也可以通过固定共轭序参量来推导。我们展示了如何在泛函重整化群方法中实现这些边界条件。我们推导并比较了φ^4理论中相应的流方程，并表明与伊辛不动点附近相关三点顶点线性化流相关联的一些标度变量和标度指数依赖于边界条件。我们还讨论了弹性对伊辛临界性的影响。在这种情况下，当我们在恒定应力下执行RG时，在恒定应变下获得的两个不动点（即重整化伊辛不动点和球面不动点）被移动到参数空间中物理上不可达的区域。
英文摘要
Renormalization group (RG) flows for systems subject to an external field can be derived either by fixing the field or by fixing the conjugate order parameter. We show how to implement these boundary conditions within the functional renormalization group approach. We derive and compare the corresponding flow equations for $ϕ^4$ theory and show that some scaling variables and scaling exponents associated with the linearized flow of the relevant three-point vertex in the vicinity of the Ising fixed point depend on the boundary conditions. We also discuss the effect of elasticity on Ising criticality. In this case two of the fixed points (namely the renormalized Ising fixed point and the spherical fixed point) obtained for constant strain are shifted to physically inaccessible regimes of parameter space when we perform the RG at constant stress.
发表机构
- Institut für Theoretische Physik, Universität Frankfurt（法兰克福大学理论物理研究所）
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