LARGE N EXPANSION FOR FRUSTRATED AND DOPED QUANTUM ANTIFERROMAGNETS
LARGE N EXPANSION FOR FRUSTRATED AND DOPED QUANTUM ANTIFERROMAGNETS
A large N expansion technique, based on symplectic (Sp(N)) symmetry, for frustrated magnetic systems is studied. The phase diagram of a square lattice, spin S, quantum antiferromagnet with first, second and third neighbor antiferromagnetic coupling (the J_1-J_2-J_3 model) is determined in the large-N limit and consequences of fluctuations at finite …