On free massless (pseudo)scalar quantum field theory in 1+1-dimensional space-time

We construct a consistent quantum field theory of a free massless (pseudo)scalar field in 1+1-dimensional space-times free of infrared divergences. We show that a continuous symmetry of (pseudo)scalar field translations is spontaneously broken. Goldstone bosons appear as quanta of a free massless (pseudo)scalar field. We show that the main inequality between vacuum expectation values of certain operators which has been used for the derivation of the Mermin-Wagner-Hohenberg theorem is fulfilled in the quantum field theory of a free massless (pseudo)scalar field free of infrared divergences.Comment: 20 pages, Latex, no figures, the manuscript is revised according to the version accepted for publication in EPJ

Spontaneous Breaking of Chiral Symmetry as a Consequence of Confinement

We show that at the leading order in the large-$N$ expansion a lattice QCD motivated linear rising confinement potential at large distances leads to a non-local four-quark interaction that realizes spontaneous breaking of chiral symmetry (SBCS) in the same way the Nambu-Jona-Lasinio model does. The dynamical quark mass $m$, which represents the solution of the gap-equation, is proportional to the square root of the string tension $\sigma$ and takes the form at the leading order in the large-$N$ expansion $m=2 \sqrt{\sigma}/\pi$ with $\sigma=0.27$ GeV$^2$. The Nambu-Jona-Lasinio phenomenological constant $G_1$, which is responsible for SBCS, is expressed in terms of the string tension and the confinement radius.Comment: 10 pages, 0 figures, latex, IK-TUW-Preprint 930540

Dynamics of low-energy nuclear forces for electromagnetic and weak reactions with the deuteron in the Nambu-Jona-Lasinio model of light nuclei

A dynamics of low-energy nuclear forces is investigated for low-energy electromagnetic and weak nuclear reactions with the deuteron in the Nambu-Jona-Lasinio model of light nuclei by example of the neutron-proton radiative capture (M1-capture) n + p -> D + photon, the photomagnetic disintegration of the deuteron photon + D -> n + p and weak reactions of astrophysical interest. These are the solar proton burning p + p -> D + positron + nu_e, the pep-process p + electron + p -> D + nu_e and the neutrino and anti-neutrino disintegration of the deuteron caused by charged nu_e + D -> electron + p + p, anti-nu_e + D -> positron + n + n and neutral nu_e(anti-nu_e) + D -> nu_e(ant-nu_e) + n + p weak currents.Comment: 49 pages, 3 Postscript figures, Latex. Eur. Phys. J. A8 (in press