  We investigate the ground state of a free massless (pseudo)scalar field in
1+1-dimensional space-time. We argue that in the quantum field theory of a free
massless (pseudo)scalar field without infrared divergences (Eur. Phys. J. C24,
653 (2002)) the ground state can be represented by a tensor product of wave
functions of the fiducial vacuum and of the collective zero-mode, describing
the motion of the ``center of mass'' of a free massless (pseudo)scalar field.
We show that the bosonized version of the BCS wave function of the ground state
of the massless Thirring model obtained in (Phys.Lett. B563, 231 (2003))
describes the ground state of the free massless (pseudo)scalar field.
