Search

We argue that certain specific gluon excitations, other than conventional glueballs, can propagate freely outside of hadrons and glueballs. We begin with the result that the Abelian generators of $SU(N)$ QCD can be meaningfully isolated by the Cho-Faddeev-Niemi-Shabanov decomposition. It has already been shown by Cho \emph{et. al.} that the corresponding gluon excitations have a gauge transformation whose form indicates that they are physical entities of neutral colour charge. We contend that this colour neutrality permits them to propagate freely, albeit with an effective mass due to interaction with the confining chromomonopole condensate. According to the dual-superconductor model of the QCD vacuum, this mass has an upper bound of $k_B T_c \sqrt{2}$. We conclude with some expected experimental signatures., Comment: 8 pages, LaTeX svjour.cls Discussion improved, especially concerning the nonconfinement of Abelian gluons. Discussion of internucleon potential greatly shortened. Mass estimate refined

I consider the monopole condensate of five colour QCD. The naive lowest energy state is unobtainable at one-loop for five or more colours due to simple geometry. The consequent adjustment of the vacuum condensate generates a hierarchy of confinement scales in a natural Higgs-free manner. QCD and QED-like forces emerge naturally, acting upon matter fields that may be interpreted as down quarks, up quarks and electrons., Comment: 15 pages, latex

I consider the monopole condensate of five color QCD. The naive lowest energy state is unobtainable at one-loop for five or more colors due to simple geometric considerations. The consequent adjustment of the vacuum condensate generates a hierarchy of confinement scales in a natural Higgs-free manner. The accompanying symmetry hierarchy contains hints of standard model phenomenology., Comment: 9 pages, PTP class file, discussion at bottom of page 5 corrected

Abelian dominance is used to reformulate the QCD Lagrangian as a sum over the roots of Lie group representation theory. This greatly facilitates extending the SU(2) magnetic ground state energy spectrum, several arguments for the stability of the magnetic ground state, and the Faddeev-Skyrme model to arbitrary SU(N) QCD., Comment: 12 pages, errors corrected

I construct an isotropic, gauge invariant monopole condensate in SU(2) QCD. It provides a suitable, gauge-invariant vacuum for the dual-Meissner effect to provide QCD colour confinement without violating the isotropy of real space., Comment: 5 pages, latex, new submission 18/10/2007, typos corrected

It is argued that the ground state of three- and four-colour QCD contains a monopole condensate, necessary for the dual Meissner effect to be the mechanism of confinement, and support its stability on the grounds that it gives the off-diagonal gluons an effective mass sufficient to remove the unstable ground state mode., Comment: jhep.cls, typos corrected, references added, some content deleted

The effects of light propagation in constant magnetic and electric backgrounds are considered in the framework of the effective action approach. We use the exact analytic series representation for the one-loop effective action of QED and apply it to the birefringence effect. Analytical results for the light velocity modes are obtained for weak and strong field regime. We present asymptotic formulae for the light velocity modes for the ultra strong magnetic field which can be realized in some neutron stars., Comment: 9 pages, 4 figs, accepted by Phys. Rev. D

We utilise a non-local gauge transform which renders the entire action of SUSY QED invariant and respects the SUSY algebra modulo the gauge-fixing condition, to derive two- and three-point ghost-free SUSY Ward identities in SUSY QED. We use the cluster decomposition principle to find the Green's function Ward identities and then takes linear combinations of the latter to derive identities for the proper functions., Comment: 20 pages, no figures, typos corrected

We study the SUSY breaking of the covariant gauge-fixing term in SUSY QED and observe that this corresponds to a breaking of the Lorentz gauge condition by SUSY. Reasoning by analogy with SUSY's violation of the Wess-Zumino gauge, we argue that the SUSY transformation, already modified to preserve Wess-Zumino gauge, should be further modified by another gauge transformation which restores the Lorentz gauge condition. We derive this modification and use the resulting transformation to derive a Ward identitiy relating the photon and photino propagators without using ghost fields. Our transformation also fulfills the SUSY algebra, modulo terms that vanish in Lorentz gauge.

We resolve the controversy on the stability of the monopole condensation in the one-loop effective action of SU(2) QCD by calculating the imaginary part of the effective action with two different methods at one-loop order. Our result confirms that the effective action for the magnetic background has no imaginary part but the one for the electric background has a negative imaginary part. This assures that the monopole condensation is indeed stable, but the electric background becomes unstable due to the pair-annihilation of gluons., Comment: 13 pages, 2 figures

We propose to resolve the controversy regarding the stability of the monopole condensation in QCD by calculating the imaginary part of the one-loop effective action perturbatively. We calculate the imaginary part perturbatively to the order $g^2$ with two different methods, with Fyenman diagram and with Schwinger's method. Our result shows that with the magnetic background the effective action has no imaginary part, but with the electric background it acquires a negative imaginary part. This strongly indicates a stable monopole condensation in QCD., Comment: 5 pages, 2 figures, references added, MPLA in press

We dispute a recent claim for a nonperturbative nonrenormalisation theorem stating that mass cannot be spontaneously generated in supersymmetric QED. We also extend a long-standing perturbative result, namely that the effective potential is zero to all orders of perturbation theory, to the nonperturbative regime for arbitrary numbers of flavours., Comment: 9 pages LaTeX

We derive the complete set of supersymmetric Ward identities involving only two- and three- point proper vertices in supersymmetric QED. We also present the most general form of the proper vertices consistent with both the supersymmetric and U(1) gauge Ward identities. These vertices are the supersymmetric equivalent of the non supersymmetric Ball-Chiu vertices., Comment: seventeen pages latex

We describe the investigation of spontaneous mass-generation and chiral symmetry breaking in supersymmetric QED3 using numerical solutions of the Dyson-Schwinger equation together with the CJT effective action and supersymmetric Ward identities. We find that, within the quenched bare approximation, the chirally symmetric solution is favoured., Comment: 14 pages, latex, 5 figures, typo corrected and slight re-wording on pages 7,8

Supersymmetry is studied in 2+1 dimensions. In addition to the multiplets corresponding to those in 3+1 dimensions the Clifford algebra allows an extra set. When the extra chiral multiplet is included, formulating supersymmetric QED3 in the manner of Wess and Zumino yields a lagrangian with a richer 'chiral' symmetry than that derived from supersymmetric QED by dimensional reduction., Comment: Paper withdrawn. The `P'-multiplets are really just another way of writing the ordinary multiplet with a gamma_{45} in front of the fermions and negative signs in front of some of the bosons