The numerical value for a universal quantity of a two-dimensional dimerized quantum antiferromagnet

The numerical value of a universal quantity associated with the quantum critical regime, namely χuc2/T, for two-dimensional (2D) dimerized spin-1/2 antiferromagnet is calculated using Monte Carlo simulations (QMC). Here χu, c, and T are uniform susceptibility, spin-wave velocity, temperature, respectively. By simulating large lattices at moderately low temperatures, we find χuc2/T∼0.32. Our estimation χuc2/T deviates from related analytic prediction but agrees recent calculations other 2D antiferromagnets.