Specific heat of the quantum Heisenberg antiferromagnet on the kagomé lattice

We propose a numerical technique, the forced-oscillator method, to investigate finite-temperature properties of quantum spin systems. The space and time complexity of this method are linear in the matrix dimension, which should be compared with the square or quadratic dependence of conventional methods. We apply this method to calculations of the specific heat of the spin-1/2 quantum Heisenberg antiferromagnet on the kagome$iaa- lattice. We find only a single-peak in contrast to a double-peak structure claimed in the literature.