Unconditional Pointer States from Conditional Master Equations

Abstract

When part of the environment responsible for decoherence is used to extract information about the decohering system, the preferred {\it pointer states} remain unchanged. This conclusion -- reached for a specific class of models -- is investigated in a general setting of conditional master equations using suitable generalizations of predictability sieve. We also find indications that the einselected states are easiest to infer from the measurements carried out on the environment.

4 pages, 3 .eps figures; final version to appear in Phys.Rev.Lett