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arXiv · 1005.4977

Criticality of the Mean-Field Spin-Boson Model: Boson State Truncation and Its Scaling Analysis

Yan-Hua Hou·Ning-Hua Tong
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Abstract

The spin-boson model has nontrivial quantum phase transitions at zero temperature induced by the spin-boson coupling. The bosonic numerical renormalization group (BNRG) study of the critical exponents $\beta$ and $\delta$ of this model is hampered by the effects of boson Hilbert space truncation. Here we analyze the mean-field spin boson model to figure out the scaling behavior of magnetization under the cutoff of boson states $N_{b}$. We find that the truncation is a strong relevant operator with respect to the Gaussian fixed point in $0 1/2$, the truncation produces no effect. Implications of these findings to the BNRG study are discussed.

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Yan-Hua Hou, Ning-Hua Tong. 2010-05-27. Criticality of the Mean-Field Spin-Boson Model: Boson State Truncation and Its Scaling Analysis. https://doi.org/10.1140/epjb/e2010-10426-0

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