Work fluctuations and work probability distributions are fundamentallydifferent in systems with short- ranged versus long-ranged correlations.Specifically, in systems with long-ranged correlations the work distribution isextraordinarily broad compared to systems with shortranged correlations. Thisdifference profoundly affects the possible applicability of fluctuationtheorems like the Jarzynski fluctuation theorem. The Heisenberg ferromagnet ,well below its Curie temperature, is a system with long-ranged correlations invery low magnetic fields due to the presence of Goldstone modes. As themagnetic field is increased the correlations gradually become short-ranged.Hence, such a ferromagnet is an ideal system for elucidating the changes of thework probability distribution as one goes from a domain with long-rangedcorrelations to a domain with short-ranged correlations by tuning the magneticfield. A quantitative analysis of this crossover behaviour of the workprobability distribution and the associated fluctuations is presented.
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