  The symmetry between the creation of pairs of massless bosons or fermions by
accelerated mirror in 1+1 space and the emission of single photons or scalar
quanta by electric or scalar charge in 3+1 space is deepened in this paper. The
relation of Bogoliubov coefficients with Fourier's components of current or
charge density leads to the coicidence of the spin of any disturbances bilinear
in scalar or spinor field with the spin of quanta emitted by the electric or
scalar charge. The mass and invariant momentum transfer of these disturbances
are essential for the relation of Bogoliubov coefficients with Green's
functions of wave equations both for 1+1 and 3+1 spaces. Namely the relation
(20) leads to the coincidence of the self-action changes and vacuum-vacuum
amplitudes for the accelerated mirror in 1+1 space and charge in 3+1 space.
Thus, both invariants of the Lorentz group, spin and mass, perform intrinsic
role in established symmetry. The symmetry embraces not only the processes of
real quanta radiation. It extends also to the processes of the mirror and the
charge interactions with the fields carring spacelike momenta. These fields
accompany their sources and define the Bogoliubov matrix coefficients
\alpha^{B,F}. It is shown that the traces of \alpha^{B,F} describe the vector
and scalar interactions of accelerated mirror with uniformly moving detector.
This interpretation rests essentially on the relation (100) between the
propagators of the waves with spacelike momenta in 2- and 4-dimentional spaces.
The traces of \alpha^{B,F} coincide actually with the products of the mass
shift \Delta m_{1,0} of accelerated electric or scalar charge and the proper
time of the shift formation. The symmetry fixes the value of the bare fine
structure constant \alpha_0=1/4\pi.
