We revisit Fradkin and Raby's real-space renormalization-group method to study the quantum Z_2 gauge theory defined on links forming a two-dimensional square lattice. Following an old suggestion of theirs, systematic perturbation expansion developed by Hirsch Mazenko is used improve algorithm second order in intercell coupling, thereby incorporating effects discarded higher energy states. A car...

In this note we give some remarks on the BRST formulation of a renormalizable and diffemorphism invariant 4D quantum gravity recently proposed by the author, which satisfies the integrability condition by Riegard, Fradkin and Tseytlin at the 2-loop level. Diffeomorphism invariance requires an addition of the Wess-Zumino action, from which the Weyl action can be induced by expanding around a vac...

We work out the description of gauge symmetry unimodular gravity in constrained Hamiltonian formalism. In particular, we demonstrate how transversality conditions restricting diffeomorphism parameters emerge from algebra constraints. The alternative form is long known as parametrizing volume preserving diffeomorphisms by unrestricted two-forms instead transverse vector fields. This reducible. t...

The Ritus’ Ep eigenfunction method is extended to the case of spin-1 charged particles in a constant electromagnetic field and used to calculate the one-loop neutrino self-energy in the strong-field approximation me ≪ eB ≪ M2 W . The implications of the obtained results for neutrino oscillations in the early Universe, assuming the existence of a sufficiently large (me ≪ eB ≪ mμ) primordial magn...

We review our work on computations of the quantum corrections to the mass and the central charge of the susy kink. For the mass corrections, we find that the widely used momentum cut-off scheme gives an incorrect result, but we deduce through smoothing of the cut-off an extra term in the mass formula, which produces the correct result. We discover the importance of boundary effects for the mode...

One may introduce at least three different Lie algebras in any Lagrangian field theory : (i) the Lie algebra of local BRST cohomology classes equipped with the odd Batalin-Vilkovisky antibracket, which has attracted considerable interest recently ; (ii) the Lie algebra of local conserved currents equipped with the Dickey bracket ; and (iii) the Lie algebra of conserved, integrated charges equip...