Quantum Stability for the Heisenberg Ferromagnet

Understand

Highly spinning classical strings on RxS^3 are described by the Landau-Lifshitz model or equivalently by the Heisenberg ferromagnet in the thermodynamic limit.

• The spectrum of this model can be given in terms of spectral curves.
• However, it is a priori not clear whether any given admissible spectral curve can actually be realised as a solution to the discrete Bethe equations, a property which can be referred to as stability.
• In order to study the issue of stability, we find and explore the general two-cut solution or elliptic curve.