Title:
Interacting N-vector order parameters with O(N) symmetry
Authors:
A.Pelissetto
(Dip. Fisica dell'Università di Roma ``La Sapienza''
and INFN, P.le Moro 2, I-00185 Roma, Italy)
, E.Vicari
(Dip. Fisica dell'Università di Pisa and INFN, V. Buonarroti 2,
I-56127 Pisa, Italy)
We consider the critical behavior of the most general system of two N-vector order parameters that is O(N) invariant. We show that it may have a multicritical transition with enlarged symmetry controlled by the chiral O(2) \otimes O(N) fixed point. For N=2,3,4, if the system is also invariant under the exchange of the two order parameters and under independent parity transformations, one may observe a critical transition controlled by a fixed point belonging to the mn model. Also in this case there is a symmetry enlargement at the transition, the symmetry being [SO(N)⊕ SO(N)] \otimes C_{2}, where C_{2} is the symmetry group of the square.
Key words:
N-vector model, O(N) symmetry, multicritical
transitions
PACS:
05.70.Jk, 64.60.Fr, 75.10.Hk
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