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arXiv · 1805.00623

Criticality of the low-frequency conductivity for the bilayer quantum Heisenberg model

Y. Nishiyama
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Abstract

The criticality of the low-frequency conductivity for the bilayer quantum Heisenberg model was investigated numerically. The dynamical conductivity (associated with the O$(3)$ symmetry) displays the inductor $σ(ω) =(iωL)^{-1}$ and capacitor $i ωC$ behaviors for the ordered and disordered phases, respectively. Both constants, $C$ and $L$, have the same scaling dimension as that of the reciprocal paramagnetic gap $Δ^{-1}$. Then, there arose a question to fix the set of critical amplitude ratios among them. So far, the O$(2)$ case has been investigated in the context of the boson-vortex duality. In this paper, we employ the exact diagonalization method, which enables us to calculate the paramagnetic gap $Δ$ directly. Thereby, the set of critical amplitude ratios as to $C$, $L$ and $Δ$ are estimated with the finite-size-scaling analysis for the cluster with $N \le 34$ spins.

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Y. Nishiyama. 2018-05-02. Criticality of the low-frequency conductivity for the bilayer quantum Heisenberg model. https://doi.org/10.1140/epjb%2Fe2018-80707-7

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