Critical behavior of CP(1) at theta=pi, Haldane's conjecture, and the relevant universality class.
Using an approach to analyze the theta dependence of systems with a theta term we recently proposed, the critical behavior of CP(10 at theta=pi is studied. We find a region outside the strong coupling regime where Haldane's conjecture is verified. The critical line, however, does not belong to the universality class of the Wess-Zumino-Novikov-Witten model at topological coupling k=1 since it shows continuously varying critical exponents.
Departamento de Física Teórica, Universidad de Zaragoza, Cl. Pedro Cerbuna 12, E-50009 Zaragoza, Spain.
Vicente
V
Azcoiti
Giuseppe
G
Di Carlo
Angelo
A
Galante