The Dilute Quantum Heisenberg Antiferromagnet

Series expansions are used to treat the randomly diluted spin‐1/2 Heisenberg antiferromagnet at zero temperature. A series is obtained at zero temperature in powers of the concentration for many correlation functions and for the correlation length from which static, dynamic, and crossover exponents are estimated. The correlation length exponent is found to be 0.77±0.10 in two dimensions. The critical concentration for the appearance of long‐range order is indistinguishable from the percolation threshold.