  In order to have a chance to make a real quantum computer it is important to
find the entanglement phenomenon on mesoscopic level since technology can not
be able in the visible future to work on atomic level. It is known that the
entanglement (the EPR correlation) violates the principle of local realism.
Existence of EPR correlation on a level higher than atomic one violates both
local and macroscopic realism. In order to clear possibility of this violation
the fundamental difference between applications of the principles of quantum
mechanics on atomic and higher level is considered. Mysterious nature of some
macroscopic quantum phenomena is accentuated. Experimental verification of the
entanglement possibility in superconductor structure is proposed.
