The infinitesimal unitary transformation, introduced recently by F. Wegner, to bring the Hamiltonian to diagonal (or band diagonal) form, is applied to the Hamiltonian theory as an exact renormalization scheme. We consider QED on the light front to illustrate the method. The low-energy generated interaction, induced in the renormalized Hamiltonian to the order α, is shown to be negative to insu...

In this work, we present a brief but insightful overview of the gauge theories, which are defined on $ n $-dimensional lattices by using finite groups, in order to show how they can be interpreted as Hamiltonian system with constraints, analogous what happens classical (continuous) (field) theories. As interpretation is not usually explored literature that discusses/introduces concept lattice t...

This paper develops the reduction theory of implicit Hamiltonian systems admitting a symmetry group at a singular value of the momentum map. The results naturally extend those known for (explicit) Hamiltonian systems described by Poisson brackets. keywords: implicit Hamiltonian systems, Dirac structures, symmetry, reduction

We investigate Hamiltonian systems with two degrees of freedom by using renormalization group method. We show that the original Hamiltonian systems and the renormalization group equations are integrable if the renormalization group equations are Hamiltonian systems up to the second leading order of small parameter. To understand temporal evolutions of Hamiltonian systems, one useful method is t...

We address the problem of computing the fundamental group of a symplectic S-manifold for non-Hamiltonian actions on compact manifolds, and for Hamiltonian actions on non-compact manifolds with a proper moment map. We generalize known results for compact manifolds equipped with a Hamiltonian S-action. Several examples are presented to illustrate our main results.

We address the problem of computing the fundamental group of a symplectic S1-manifold for non-Hamiltonian actions on compact manifolds, and for Hamiltonian actions on non-compact manifolds with a proper moment map. We generalize known results for compact manifolds equipped with a Hamiltonian S1-action. Several examples are presented to illustrate our main results.

We show that the so-called Renormalization Group pathologies in low temperature Ising models are due to the fact that the renormalized Hamiltonian is deened only almost everywhere (with respect to the renormalized Gibbs measures). We construct this renormalized Hamiltonian using a Renormalization Group method developed for random systems and we show that the pathologies are analogous to Griiths...