Low-Temperature Properties of the Two-Impurity Kondo Hamiltonian

For the two-impurity Kondo system, the low-temperature properties—impurity spin-spin correlation function, susceptibilities, specific heat, and Wilson ratio—are strongly nonuniversal functions of the ratio $\frac{I_0}{T_{\mathrm{K}}}$ of the Ruderman-Kittel-Kasuya-Yosida coupling to the single-impurity Kondo temperature. In particular, there is a new unstable fixed point for an antiferromagnetic coupling with $\frac{I_0}{T_{\mathrm{K}}}\simeq -2.2\mathrm{}$. The calculations utilize a newly found symmetry of Kondo Hamiltonians, axial charge.