标题： 二聚化量子自旋系统的自旋功能重整化群 显示英文标题

标题： Spin functional renormalization group for dimerized quantum spin systems

摘要： 我们使用Krieg和Kopietz [Phys. Rev. B 99, 060403(R) (2019)]提出的自旋功能重整化群方法研究了二聚化的量子自旋系统，该方法直接关注物理自旋关联函数，并避免用费米子或玻色子辅助算符来表示自旋。从独立的二聚体作为重整化群流方程的初始条件出发，我们在所有温度下获得了三重态激发谱以及量子顺磁相、铁磁相和热无序相中的磁化强度。此外，我们计算了三维弱耦合二聚化自旋系统的完整相图，包括两个量子临界点处正确的平均场临界指数。 显示英文摘要

摘要： We investigate dimerized quantum spin systems using the spin functional renormalization group approach proposed by Krieg and Kopietz [Phys. Rev. B 99, 060403(R) (2019)] which directly focuses on the physical spin correlation functions and avoids the representation of the spins in terms of fermionic or bosonic auxiliary operators. Starting from decoupled dimers as initial condition for the renormalization group flow equations, we obtain the spectrum of the triplet excitations as well as the magnetization in the quantum paramagnetic, ferromagnetic, and thermally disordered phases at all temperatures. Moreover, we compute the full phase diagram of a weakly coupled dimerized spin system in three dimensions, including the correct mean field critical exponents at the two quantum critical points.