TY - JOUR A1 - Pikovskij, Arkadij A1 - Gupta, Shamik A1 - Teles, Tarcisio N. A1 - Benetti, Fernanda P. C. A1 - Pakter, Renato A1 - Levin, Yan A1 - Ruffo, Stefano T1 - Ensemble inequivalence in a mean-field XY model with ferromagnetic and nematic couplings JF - Physical review : E, Statistical, nonlinear and soft matter physics N2 - We explore ensemble inequivalence in long-range interacting systems by studying an XY model of classical spinswith ferromagnetic and nematic coupling. We demonstrate the inequivalence bymapping themicrocanonical phase diagram onto the canonical one, and also by doing the inverse mapping. We show that the equilibrium phase diagrams within the two ensembles strongly disagree within the regions of first-order transitions, exhibiting interesting features like temperature jumps. In particular, we discuss the coexistence and forbidden regions of different macroscopic states in both the phase diagrams. Y1 - 2014 U6 - https://doi.org/10.1103/PhysRevE.90.062141 SN - 1539-3755 SN - 1550-2376 VL - 90 IS - 6 PB - American Physical Society CY - College Park ER -