arXiv:0707.2866 · Physical Review B
Magnetic-glassy multicritical behavior of the three-dimensional ±J Ising model
Martin Hasenbusch B, Francesco Parisen Toldin, Andrea Pelissetto C, Ettore Vicari
Abstract
We consider the three-dimensional $\ifmmode\pm\else\textpm\fi{}J$ model defined on a simple cubic lattice and study its behavior close to the multicritical Nishimori point, where the paramagnetic-ferromagnetic, the paramagnetic-glassy, and the ferromagnetic-glassy transition lines meet in the $T\text{\ensuremath{-}}p$ phase diagram ($p$ characterizes the disorder distribution and gives the fraction of ferromagnetic bonds). For this purpose, we perform Monte Carlo simulations on cubic lattices of size $L\ensuremath{\leqslant}32$ and a finite-size-scaling analysis of the numerical results. The magnetic-glassy multicritical point is found at ${p}^{*}=0.768\phantom{\rule{0.2em}{0ex}}20(4)$, along the Nishimori line given by $2p\ensuremath{-}1=\mathrm{tanh}(J∕T)$. We determine the renormalization-group dimensions of the operators that control the renormalization-group flow close to the multicritical point, ${y}_{1}=1.02(5)$, ${y}_{2}=0.61(2)$, and the susceptibility exponent $\ensuremath{\eta}=\ensuremath{-}0.114(3)$. The temperature and crossover exponents are $\ensuremath{\nu}=1∕{y}_{2}=1.64(5)$ and $\ensuremath{\phi}={y}_{1}∕{y}_{2}=1.67(10)$, respectively. We also investigate the model-$A$ dynamics, obtaining the dynamic critical exponent $z=5.0(5)$.