  This paper introduces a quasiequilibrium one-dimensional Bose-Einstein
condensation of photons trapped in a microtube. Light modes with a cut-off
frequency (a photon's "mass") interact through different processes of
absorption, emission, and scattering on molecules and atoms. In this paper, we
study the conditions for the one-dimensional condensation of light and the role
of photon-photon interactions in the system. The technique in use is the
Matsubara's Green's functions formalism modified for the quasiequilibrium
system under study.
