Narrow Results

To show the important role that geometry may play in the problem of confining particles to our four-dimensional spacetime, we consider a five-dimensional model where fermions are confined in a hypersurface due to an interaction with geometric fields. We use two different fields which appear in non-Riemannian geometries, namely, the Weyl one-form and the torsion two-form. We show that for suitable choices of these fields one manages to confine fermions in our brane (our four-dimensional world). It turns out that this confinement is independent of the energy and the mass of the fermions.

We briefly review motivation and results of the approach to QCD vacuum as a medium describable in terms of statistical ensemble of almost everywhere constant Abelian (anti-)self-dual gluon fields. An overview of the hadronization formalism based on this ensemble is presented. New results for radial excitations of light, heavy-light mesons and heavy quarkonia are presented. A possible interrelation between the present approach and holographic QCD with harmonic confinement is outlined.

A form to describe hadron strong decays is in terms of quark and gluon degrees of freedom in microscopic decay models. Initially we assume that strong decays are driven by the same inter-quark Hamiltonian which determines the spectrum, and that it incorporates gaussian confinement. An $A\to BC$ decay matrix element of the JKJ Hamiltonian involves a pair-production current matrix elements times a scattering matrix element. Diagrammatically this corresponds to an interaction between an initial line and produced pair. In this work we apply the model to the light meson sector and calculate the decay rate, comparing with the experimental values.

Recently computational resource of quantum computers sounds growing well. In this article, we discuss how we can apply this development to numerically simulate quantum field theories. In contrast to the conventional approach by (Marlov chain) Monte Carlo method suffering from the infamous sign problem, we work in Hamilton formalism and adopt quantum algorithms which do not rely on Monte Carlo sampling. After brief discussion on how to put quantum field theories on quantum computers, we present our recent numerical results on the charge-q Schwinger model, where q is an electric charge of a Dirac fermion. We observe an exotic phenomena such as negative string tension behavior in potential between heavy charged particles which essentially come from presense of non-small θ-angle.