Density matrix renormalization group approach to a two-dimensional bosonic model

Density matrix renormalization group (DMRG) is applied to a (1+1)-dimensional λφ4 model to study spontaneous breakdown of discrete Z2 symmetry numerically. We obtain the critical coupling (λ/μ2)c=59.89+/-0.01 and the critical exponent β=0.1264+/-0.0073, which are consistent with the Monte Carlo and the exact results, respectively. The results are based on extrapolation to the continuum limit with lattice sizes L=250, 500, and 1000. We show that the lattice size L=500 is sufficiently close to the the limit L->∞ [T. Sugihara, JHEP 0405 (2004) 007]