We study the global phase diagram of the Infinite-range Blume-Emery-Griffiths model both in the canonical and in the microcanonical ensembles. The canonical phase diagram shows first-order and continuous transition lines separated by a tricritical point. We find that below the tricritical point, when the canonical transition is first order, the phase diagrams of the two ensembles disagree. In this region the microcanonical ensemble exhibits energy ranges with negative specific heat and temperature jumps at transition energies. These results can be extended to weakly decaying nonintegrable
Inequivalence of ensembles in a system with long-range Interactions / Barre, J.; Mukamel, D.; Ruffo, S.. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - 87:3(2001). [10.1103/PhysRevLett.87.030601]
Inequivalence of ensembles in a system with long-range Interactions
Ruffo, S.
2001-01-01
Abstract
We study the global phase diagram of the Infinite-range Blume-Emery-Griffiths model both in the canonical and in the microcanonical ensembles. The canonical phase diagram shows first-order and continuous transition lines separated by a tricritical point. We find that below the tricritical point, when the canonical transition is first order, the phase diagrams of the two ensembles disagree. In this region the microcanonical ensemble exhibits energy ranges with negative specific heat and temperature jumps at transition energies. These results can be extended to weakly decaying nonintegrableI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.