Papers by alex kalloniatis
Using DLCQ as a nonperturbative method, we test Fock-space truncations in QCD 1+1 by studying the... more Using DLCQ as a nonperturbative method, we test Fock-space truncations in QCD 1+1 by studying the mass spectra of hadrons in colour SU(2) and SU(3) at finite harmonic resolution K. We include qqqq states for mesons and up to qqqqq states for baryons. With this truncation, we give 'predictions' for the masses of the first five states where finite K effects are minimal.
Singular gauge fields in the partition function for QCD can lead to a domain-like picture for the... more Singular gauge fields in the partition function for QCD can lead to a domain-like picture for the QCD vacuum by virtue of constraints on quantum fluctuations at the singularities. With a simple model of hyperspherical domains with interiors of constant field strength we show that the main features of gluon condensation and an area law for static quarks can be realised. The Dirac operator in such a background is exactly soluble. Chirality properties of the solutions show agreement with recent lattice results. 1.
We suggest that clusters or domains of topological charge and action density occur in the QCD vac... more We suggest that clusters or domains of topological charge and action density occur in the QCD vacuum as an effect of singularities in gauge fields and can simultaneously lead to confinement and chiral symmetry breaking. The string constant, condensates and topological susceptibility are estimated within a simplified model of hyperspherical domains with interiors of constant field strength with reasonable values obtained. Propagators of dynamical quarks and gluons have compact support in configuration space, thus having entire Fourier transforms, which gives rise to their confinement.
AIP Conference Proceedings, 2005
The prediction that CP‐symmetry can be spontaneously broken for discrete values of the θ paramete... more The prediction that CP‐symmetry can be spontaneously broken for discrete values of the θ parameter in QCD is a constraint on self‐consistent models of the non‐perturbative QCD vacuum. We show that the domain model, which successfully exhibits confinement, spontaneous symmetry breaking and resolution of the axial U(1) problem, correctly reproduces this feature.
We address the computation of the determinant for the Dirac operator corresponding to a quark pro... more We address the computation of the determinant for the Dirac operator corresponding to a quark propagating in a background gluon field of the following type: the gauge field is covariantly constant and self-dual inside a hypersphere and with quark fields satisfying bag-like (chiral-violating) boundary conditions at the surface of the hypersphere. We find that the parity odd part of the logarithm of the determinant corresponds to the Abelian anomaly. However the parity even part also depends on the chiral angle associated with the boundary. This unexpected dependence is discussed.
International Europhysics Conference on High Energy Physics, 1999
SU(2) Yang-Mills theory at finite temperature is probed by a homogeneous chromomagnetic field. We... more SU(2) Yang-Mills theory at finite temperature is probed by a homogeneous chromomagnetic field. We use a recent axial gauge formulation which has the feature of respecting Z 2-symmetry in perturbation theory. In the Z 2-symmetric phase a temperature-dependent mass term and antiperiodic boundary conditions arise, providing stabilisation against magnetic field formation at sufficiently high temperature. In the broken phase the combined constraints of thermodynamic and magnetic stability lead to a slow approach to the Stefan-Boltzmann limit, as seen in lattice SU(2) gauge theory.
Lecture Notes in Physics, 1990
We derive the propagator for the abelian gauge field in the temporal gauge using parallel transpo... more We derive the propagator for the abelian gauge field in the temporal gauge using parallel transport from the Coulomb gauge, the quantisation having already been done in the Coulomb gauge. The resulting prescription for the traditionally problematic spurious pole in the longitudinal propagator falls into the class of prescriptions in the literature which break time-translational invariance.
Philosophical Magazine Part B, 1988
Abstract Abstract A proposal to abandon the current sophisticated index scheme of the Al-Mn decag... more Abstract Abstract A proposal to abandon the current sophisticated index scheme of the Al-Mn decagonal phase has recently been advanced (Fitz Gerald, Withers, Stewart and Calka 1987), in favour of a new straightforward description. This description is based on a periodic stacking of Penrose lattices which are two-dimensional, using the natural in-plane (quasi-periodic) a 6 (n = 1 to 5) and (periodic) a 6 vectors as its basis. It affords a simpler description than the currently adopted system which is based on the lower and upper edge vectors of a (distorted icosahedral) pentagonal bipyramid model, with useful advantages for example in comparing vectors of identical quasiperiodic but different periodic components. Computing the diffraction pattern is straightforward in our description, and our simulations show excellent agreement with patterns recorded experimentally at various projection angles.
Lepton Scattering, Hadrons and QCD, 2001
Quark Confinement and the Hadron Spectrum V - Proceedings of the 5th International Conference, 2003
Physics Letters B, 2005
We propose a generalisation of the Faddeev-Popov trick for Yang-Mills fields in the Landau gauge.... more We propose a generalisation of the Faddeev-Popov trick for Yang-Mills fields in the Landau gauge. The gauge-fixing is achieved as a genuine change of variables. In particular the Jacobian that appears is the modulus of the standard Faddeev-Popov determinant. We give a path integral representation of this in terms of auxiliary bosonic and Grassman fields extended beyond the usual set for standard Landau gauge BRST. The gauge-fixing Lagrangian density appearing in this context is local and enjoys a new extended BRST and anti-BRST symmetry though the gauge-fixing Lagrangian density in this case is not BRST exact.
Nuclear Physics B - Proceedings Supplements, 2005
The results of the domain model for the QCD vacuum are reviewed. The model offers a coherent fram... more The results of the domain model for the QCD vacuum are reviewed. The model offers a coherent framework for understanding non-observability of quarks within the context of analytic confinement while simultaneously providing a mechanism for spontaneous chiral symmetry breaking and resolving the UA(1) problem. The impact of this confinement scenario at high energies is also discussed whereby the unique properties of highly excited resonances provide unambiguous signals for distinguishing this confinement mechanism from alternate scenarios.
Journal of Physics A: Mathematical and General, 1988
For atoms whose valence states obey k=n+l ordering, the author assumes a Hamiltonian H=H(k)+H(l),... more For atoms whose valence states obey k=n+l ordering, the author assumes a Hamiltonian H=H(k)+H(l), where the first term has invariance group SO(4) and is perturbed by the second. The author derives matrix representations of operators which, with angular momentum, are constants of the motion and generate such an SO(4) group.
Zeitschrift f�r Physik C Particles and Fields, 1993
Zeitschrift für Physik C Particles and Fields, 1994
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Papers by alex kalloniatis