  Relativistic quantum effects on physical observables of scalar charged
particles are studied. Possible peculiarities of their behavior that can be
verified in an experiment can confirm several fundamental conceptions of
quantum mechanics. For observables independent of charge variable, we propose
relativistic Wigner function formalism that contains explicitly the measurement
device frame. This approach can provide the description of charged particles
gas (plasma). It differs from the traditional one but is consistent with the
Copenhagen interpretation of quantum mechanics. The effects that are connected
with this approach can be observed in astrophysical objects - neutron stars.
