Sommaire:

Light-front (LF) form of quantum field theory has a few serious conceptual advantages, but also some puzzling features. In my talk, I shall suggest potential solutions to some of the LF "failures". First, presence of the vacuum "bubbles" in the Hamiltonian LF perturbation theory will be clarified. The resulting vacuum amplitudes are non-vanishing despite the notorious "triviality" of the LF vacuum and agree with the results of Feynman perturbation theory evaluated in terms of the LF variables. Next, I will show that some apparent consistency problems of the LF theory can be solved if mathematically adequate treatment is adopted. Contradictions related to the LF restriction of the two-point function are removed if the scalar field contains regularization terms in the plane-wave factors. As a consequence, the correct equal-LF time commutators are reproduced from the Pauli-Jordan function, and the sign function present in them is naturally replaced by a function suppressed for large x^- - values. The value of the two-point function at coinciding points is also correctly obtained in the Hamiltonian (”on shell”) formulation. Then a novel look at the LF zero modes will be described, based on a consistent quantization of two-dimensional massless LF fields. Finally, the operator solution of the Thirring-Wess model in the light-front formulation will be presented.

Pour plus d'informations, merci de contacter Brümmer F.