Long range interactions: order and disorder in 2D spin models
(will be presented as a poster)
Sofia Regina


Abstract
When spin Hamiltonians with long range spin-spin interactions, as for instance dipolar interactions, are considered Mermin-Wagner theorem cannot be applied in order to exclude the existence of long range order at any finite temperature in 2D systems like Heisenberg, XY or planar. Numerical results obtained by Monte Carlo simulations and low twmperature expansion lead to controversial or unclear conclusions. We study a 2D planar model with long range interactions both analytically and and numerically. This model seems to be a good model for superconductor compounds where dipolar interactions play an important role.

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Elenco dei partecipanti al convegno di Bari.

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