Renormalisation-group approach to the spin glass transition in finite magnetic fields

Renormalisation-group methods are applied in 6- epsilon dimensions in an attempt to determine the critical behaviour at the phase boundary between paramagnetic and spin glass phases in a finite magnetic field (i.e. at the de Almeida-Thouless instability). No stable fixed points, accessible from the domain of physical initial Hamiltonians, are found. Possible interpretations of this result are discussed.