Yuri Novozhilov

On the light-cone formulation of classical non-abelian gauge theory

For a classical Yang-Mills field which is periodic in the longitudinal light-cone coordinate: (a) a gauge condition is formulated, (b) the presence of field singularities in this gauge is shown, and (c) the relevance of these singularities to the topological charge is demonstrated.

Extended chiral transformations including diquark fields as parameters

Abstract We introduce an extended chiral transformation, which depends both on pseudoscalar and diquark fields as parameters, and determine its group structure. Assuming soft symmetry breaking in the diquark sector, the bosonisation of a quasi-Goldstone ud-diquark is performed. In the chiral limit the ud-diquark mass is defined by the gluon condensate, mud ≃300 MeV. The diquark charge radius is ud 2 > 1 2 ≃0.5 fm.

Chiral Parametrization of QCD Vector Field in SU(3)

The chiral parametrization of gluons in SU(3) QCD is proposed extending an approach developed earlier for SU(2) case. A color chiral field is introduced, gluons are chirally rotated, and vector component of rotated gluons is defined on condition that no new color variables appeared with the chiral field. This condition associates such a vector component with SU(3)/U(2) coset plus an U(2) field. The topological action in SU(3) QCD is derived. It is expressed in terms of axial vector component of rotated gluons. The vector field in CP^2 sector is studied in new variables of chiral parametrization.

Composite particles in QFT and collective variables

Abstract We consider the use of collective variables in quantum field theory (QFT) for description of composite particles as collective phenomena due to the strong coupling regime. We discuss two approaches, where identification of collective variables of complex quantum system does not depend on the knowledge of other degrees of freedom: (a) collective variables as parameters of group transformations changing the path integral of the system, and (b) collective variables as background fields for quantum system. In the case (a) we briefly present an approach. In the case (b) we consider quarks in an external scalar field, which serves as a collective variable in a model for composite scalar mesons.

The Klein–Fock equation, proper-time formalism and symmetry of the hydrogen atom☆

We present main points of some of Fock papers in Quantum Theory, which were not properly followed when published.

Induced action in QCD

We consider the problem of fermionic composites in the strong coupling regime of the low mass scale and not-so-low mass scale QCD. The group-theoretical approach permits easily to identify those collective variables which describe composite particles in the lowest scale part of QCD. When scale increases and in absence of new approximate symmetry, we propose to study possibilities opened by induced actions for background fields with finite composite scale which acquire dynamics due to vacuum fluctuations of quarks. We investigated an induced action for scalar mesons and found that their masses can be enhanced above double quark mass, due to condensates.

Correspondence principle and quantum gauge theories with chiral fermions

The correspondence principle is used to extend nonabelian gauge theories with chiral fermions up to anomaly-free theories by introducing unitary scalar fields. Resulting theories can be treated as a low-energy approximation to left-right theories. This approach fixes the Weinberg angle of the electroweak theory at θw=30°.