Numerical study of a two-dimensional quantum antiferromagnet with random ferromagnetic bonds
Numerical study of a two-dimensional quantum antiferromagnet with random ferromagnetic bonds
A Monte Carlo method for finite-temperature studies of the two-dimensional quantum Heisenberg antiferromagnet with random ferromagnetic bonds is presented. The scheme is based on an approximation which allows for an analytic summation over the realizations of the randomness, thereby significantly alleviating the ``sign problem'' for this frustrated spin system. The …