2020/10/09 by Ke Yang, Yang, Ke, Ning-Hua Tong +1
Physics and Astronomy · #FOS: Physical sciences #Magnetic properties of thin films #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Strongly Correlated Electrons (cond-mat.str-el) #cond-mat.str-el
paper · pdf · doi:10.48550/arxiv.2010.04398
arxiv created 2020/10/09 · openalex publication_date 2020/10/09 · arxiv updated 2020/10/12 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Using the recently developed exact numerical renormalization group (NRG) method, we analyse the NRG truncation errors δχ of the local magnetic susceptibility and δF of the free energy for the spin-boson model (SBM). We find that for temperatures higher than a crossover temperature Tcr, as the number of kept states M increases, both errors have oscillations with quasi period lnM/lnNb and the envelopes decrease as εtr=Λ^-lnM/lnNb (Nb is the number of boson states used for each bath site). For T ≪ Tcr, they decrease slower than the power law. We extract that Tcr = T∗ εtr, with T∗ being the crossover energy scale between the declocalized and the critical fixed points of SBM. The same rule applies to δχ and δF calculated from the full density matrix NRG method and is expected to hold for general impurity models, allowing accurate removal of NRG truncation errors in static quantities at high temperatures.