Quantum fluctuations in helimagnets

Abstract

The authors obtain the leading quantum corrections in S-1 to the ground-state energy and to the spin wave spectrum of a Heisenberg helimagnet. Both single and double scattering processes contribute. They find that the helix wavevector Q is not modified and the spin wave spectrum has the correct soft-mode behavior (the Goldstone mode) at k=0 and k=+or-Q as they have explicitly verified for the anisotropic next-nearest-neighbour Heisenberg mode. The Goldstone theorem for helimagnets is also briefly considered.