Аннотация:A
method
is
described
for
deriving
kinetic
equations
for
an
electron
subsystem
with
a
band
spectrum
interacting
with
a
photon
subsystem.
Kinetic
equations
with
allowance
for
the
po-
larization
are
obtained
for
the
diagonal
and
nondiagonal
(relative
to
the
bands)
elements
of
the
density
matrix.
The
polarization
leads
to
a
renormalization
of
the
photon
frequencies
and
interaction
of
the
electrons
with
one
another
through
the
exchange
of
virtual
photons.
The
relaxation
of
the
band
populations
and
the
polarization
due
to
an
external
field
are
studied
in
the
two-band
approximation
by
means
of
the
collision
integrals
obtained
in
the
method.