ar X iv : 0 90 2 . 00 45 v 1 [ he p - la t ] 3 1 Ja n 20 09 An improved lattice measurement of the critical coupling in φ 42 theory

We use Monte Carlo simulations to obtain an improved lattice measurement of the critical coupling constant [ λ/μ ] crit for the continuum (1 + 1)-dimensional (λ/4)φ theory. We find that the critical coupling constant depends logarithmically on the lattice coupling, resulting in a continuum value of [ λ/μ ] crit = 10.8 −.05, in considerable disagreement with the previously reported [ λ/μ ] crit = 10.26 −.04. Although this logarithmic behavior was not observed in earlier lattice studies, it is consistent with them, and expected analytically. Electronic address: [email protected] Electronic address: [email protected]