Related papers: Dimensionally Regularized Study of Nonperturbative…
We examine several zero-range potentials in non-relativistic quantum mechanics. The study of such potentials requires regularization and renormalization. We contrast physical results obtained using dimensional regularization and cutoff…
The analytic structure of the quark propagator in Minkowski space is more complex than in Euclidean space due to the possible existence of poles and branch cuts at timelike momenta. These singularities impose enormous complications on the…
Perturbative and non-perturbative results on the renormalization constants of the fermion field and the twist-2 fermion bilinears are presented with emphasis on the non-perturbative evaluation of the one-derivative twist-2 vector and axial…
We introduce a non-perturbative renormalization approach which identifies stable fixed points in any dimension for the Kardar-Parisi-Zhang dynamics of rough surfaces. The usual limitations of real space methods to deal with anisotropic…
Studying the strong correlation effects in interacting Dirac fermion systems is one of the most challenging problems in modern condensed matter physics. The long-range Coulomb interaction and the fermion-phonon interaction can lead to a…
In the Euclidean-space formulation of integral equations for the structure of quantum chromodynamics (QCD) bound states, the quark propagators with complex-valued momentum are densely sampled. We therefore propose an accurate and efficient…
The behaviour of the photon renormalization function in strong coupling QED has been recently studied by Kondo, Mino and Nakatani. We find that the sharp decrease in its behaviour at intermediate photon momenta is an artefact of the method…
We discuss unquenching of the three-gluon vertex via its Dyson-Schwinger equation. We review the role of Furry's theorem and present first results for the quark triangle diagrams using non-perturbatively calculated dressing functions for…
In this work, we present the quasinormal modes of a fermionic field in the background of Gauss-Bonnet-AdS black holes. We find exact solutions for $D=5$ at the fixed value $\alpha=R^2/2$ of the Gauss--Bonnet coupling constant, with $R$…
We continue the study of the ultraviolet problem for QED in d=3. The model is defined on a fine toroidal lattice and we seek control as the lattice spacing goes to zero. The problem is analyzed using Balaban's formulation of the…
We introduce a random lattice corresponding to ordinary Feynman diagrams, with 1/p-squared propagators instead of the Gaussians used in the usual strings. The continuum limit defines a new type of string action with two worldsheet metrics,…
We compute non-perturbatively the renormalisation constants of composite operators on a $16^3 \times 32 $ lattice with lattice spacing $a$ = 0.093 fm for the overlap fermion action by using the regularisation independent (RI) scheme. The…
We consider regularisation of a Yang-Mills theory by Dimensional Reduction (DRED). In particular, the anomalous dimensions of fermion masses and gauge coupling are computed to four-loop order. We put special emphasis on the treatment of…
The standard approximations of the Dyson--Schwinger equation lead to complex singularities of the fermion propagator. In three-dimensional QED one can show that this phenomenon might be related to confinement: a confining potential leads to…
Chiral symmetry breaking in QCD is studied introducing a confining effective propagator, as proposed recently by Cornwall, and considering the effect of dynamically massive gluons. The effective confining propagator has the form…
We present a non-perturbative formulation of renormalization by viewing the regularized Schwinger-Dyson hierarchy as a meromorphic connection, that is, as a D-module on the product of spacetime with the regulator disc. The irregular…
A general strategy to solve the non-perturbative renormalization problem in lattice QCD, using finite-size techniques and numerical simulations, is described. As an illustration we discuss the computation of the axial current normalization…
We study $\mathcal{N}=1$ supersymmetric three-dimensional Quantum Electrodynamics with $N_f$ two-component fermions. Due to the infra-red (IR) softening of the photon, $\ep$-scalar and photino propagators, the theory flows to an interacting…
Non-compact three-dimensional QED is studied by computer simulations to understand its chiral symmetry breaking features for different values of the number of fermion flavors N_f. We consider the four-component formulation for the fermion…
The $e^-$-$e^+$ bound state spectrum of QED3 is investigated in the quenched ladder approximation to the homogeneous Bethe-Salpeter equation with fermion propagators from a rainbow approximation Schwinger-Dyson equation. A detailed analysis…