Internal field distributions in model spin glasses

The zero temperature probability distribution P(h) of internal magnetic fields is studied, both in the Sherrington-Kirkpatrick random Ising model of a spin glass and in its natural extension to classical vector spins. Theoretical predictions and computer simulations agree that P(h) is linear for small h in the Ising case, and has a hole-P(h)=0 for h< eta -in the vector spin case.