Mechanisms of decoherence in weakly anisotropic molecular magnets

Decoherence mechanisms in crystals of weakly anisotropic magnetic molecules, such as V-15, are studied. We show that an important decohering factor is the rapid thermal fluctuation of dipolar: interactions between magnetic molecules. A model is proposed to describe the influence of this source of decoherence. Based on the exact solution of this model, we show Char ar relatively high temperatures, about 0.5 K, the quantum coherence in a V-15 molecule is not suppressed and, in principle, can be detected experimentally Therefore, these molecules may be suitable prototype systems far study of physical processes taking place in quantum computers.