Interfaces and the question of regional congruence in spin glasses - art. no. 077201

We present a general theorem restricting properties of interfaces between t hermodynamic states and apply it to the spin glass excitations observed num erically by Krzakala and Martin and separately by Palassini and Young in sp atial dimensions d = 3,4. We show that such excitations, with interface dim ension d(s) < d, cannot yield regionally congruent thermodynamic states. Mo re generally, zero density interfaces of translation-covariant excitations cannot be pinned (by the disorder) in any d but rather trust deflect to inf inity in the thermodynamic limit. Additional consequences concerning region al congruence in spin glasses and other systems are discussed.