论文标题
在波动场中自旋的固定点歼灭
Fixed point annihilation for a spin in a fluctuating field
论文作者
论文摘要
与关键自由场（Bose-Kondo模型）结合的量子自旋杂质可以表示为0+1D场理论，具有长时间的时间相互作用，衰减为$ | t-t-t-t'|^{ - （2-Δ）} $。该理论是非线性Sigma模型的更简单的类似物，其拓扑结构是较高维度的拓扑作用。在本说明中，我们表明，杂质问题的RG流动在相互作用指数的临界值$Δ_c$上显示两个非平凡的RG固定点之间的an灭。该计算以大型旋转$ S $控制。这阐明了Bose-Kondo模型的相图，并表明它是涉及较高维度的固定点歼灭和“否定点”现象的玩具模型。
A quantum spin impurity coupled to a critical free field (the Bose-Kondo model) can be represented as a 0+1D field theory with long-range-in-time interactions that decay as $|t-t'|^{-(2-δ)}$. This theory is a simpler analogue of nonlinear sigma models with topological Wess-Zumino-Witten terms in higher dimensions. In this note we show that the RG flows for the impurity problem exhibit an annihilation between two nontrivial RG fixed points at a critical value $δ_c$ of the interaction exponent. The calculation is controlled at large spin $S$. This clarifies the phase diagram of the Bose-Kondo model and shows that it serves as a toy model for phenomena involving fixed-point annihilation and "quasiuniversality" in higher dimensions.
