  Atom interferometers can be used to study phenomena leading to
irreversibility and dissipation, induced by the dynamics of fundamental objects
(strings and branes) at a large mass scale. Using an effective, but physically
consistent description in terms of a master equation of Lindblad form, the
modifications of the interferometric pattern induced by the new phenomena are
analyzed in detail. We find that present experimental devices can in principle
provide stringent bounds on the new effects.
