Let βcI be the critical inverse temperature in an Ising ferromagnet with pair interactions and let βcR be the critical temperatures in the plane rotor (classical xy model) with the same couplings. We prove that βcR ≥ 2βcI. This yields the lower bound βc ≥ 0.88 for the Kosterlitz-Thouless transition.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)