MACROSCOPIC LOCAL REALISM - HOW DO WE DEFINE IT AND IS IT COMPATIBLE WITH QUANTUM-MECHANICS

We introduce the concept of different orders (micro-through to macro-o f local realism. ''Macroscopic local realism'' states that events occu rring at a location B cannot induce (immediate! macroscopic changes to a system at a location A spatially separated from B. ''Local realism' ' in its entirety excludes all sizes of change. ''Local realism'' in i ts entirety is used by Einstein, Podolsky, and Rosen to deduce that re sults of position measurements (for certain correlated systems) are pr edetermined. The value for the predetermined position is specified wit h an uncertainty which is microscopic. ''Macroscopic local realism'' a llows one to deduce only the existence of ''elements of reality'' with a macroscopic uncertainty. While Bell's theorem invalidates local rea lism in its entirety, little is known of the validity of ''macroscopic local realism.'' We consider macroscopic experiments where the experi mental error associated with measurements is macroscopic. We formulate the Einstein-Podolsky-Rosen argument for such a macroscopic situation . We propose that violations of Bell inequalities in such macroscopic experimental situations would imply the failure of ''macroscopic local realism.'' (C) 1998 Academic Press.