Fermionization, Convergent Perturbation Theory, and Correlations in the Yang-Mills Quantum Field Theory in Four Dimensions

We show that the Yang-Mills quantum field theory with momentum and spacetime cutoffs in four Euclidean dimensions is equivalent, term by term in an appropriately resummed perturbation theory, to a Fermionic theory with nonlocal interaction terms. When a further momentum cutoff is imposed, this Fermionic theory has a convergent perturbation expansion. To zeroth order in this perturbation expansion, the correlation function $E(x,y)$ of generic components of pairs of connections is given by an explicit, finite-dimensional integral formula, which we conjecture will behave as $$E(x,y) \sim |x - y|^{-2 - 2 d_G},$$ \noindent for $|x-y|>>0,$ where $d_G$ is a positive integer depending on the gauge group $G.$ In the case where $G=SU(n),$ we conjecture that $$d_G = {\rm dim}SU(n) - {\rm dim}S(U(n-1) \times U(1)),$$ \noindent so that the rate of decay of correlations increases as $n \to \infty.$Comment: Minor corrections of notation, style and arithmetic errors; correction of minor gap in the proof of Proposition 1.4 (the statement of the Proposition was correct); further remark and references adde

Gender and educational leadership in England: a comparison of secondary headteachers' views over time

In the context of gender being a barrier to accessing leadership, this paper presents a comparison of the views of men and women head teacher (principals) of secondary schools in England in the 1990s and in 2004. The same survey instrument was used on both occasions. The perceptions of the head teachers show change in some areas and no change in others. Overall, women are more likely to become head teachers and are now less likely to be categorised into pastoral roles, but in some cases women still meet prejudice from governors and others in the wider community. Women head teachers are more likely to have partners and children than in the 1990s, sharing equally or carrying most of the domestic responsibilities, whereas male colleagues are most likely to have partners who take the majority of responsibility in the home. Essentialist stereotypes about women and men as leaders still prevail, although both the women and men head teachers see themselves as adopting a traditionally ‘feminine’ style of leadership. Women head teachers are likely to see some benefits in being a woman in a role stereotypically associated with men. However, there has been an increase in the proportion of women who feel that they have to prove their worth as a leader, and this may be linked with increased levels of accountability in schools

Heavy Quark Potential from Gauge/Gravity Duality: A Large D Analysis

The heavy-quark potential is calculated in the framework of gauge/gravity duality using the large-D approximation, where D is the number of dimensions transverse to the flux tube connecting a quark and an antiquark in a flat D+2-dimensional spacetime. We find that in the large-D limit the leading correction to the ground-state energy, as given by an effective Nambu-Goto string, arises not from the heavy modes but from the behavior of the massless modes in the vicinity of the quark and the antiquark. We estimate this correction and find that it should be visible in the near-future lattice QCD calculations of the heavy-quark potential.Comment: 22 pages, 5 Figures. v2: references added, typos corrected and, Sec. 4 rewritten with an expanded non-perturbative discussion of the corrections to the Arvis potential arising from the massless modes near the boundary of the qcd strin

Quantized gravitational waves in the Milne universe

The quantization of gravitational waves in the Milne universe is discussed. The relation between positive frequency functions of the gravitational waves in the Milne universe and those in the Minkowski universe is clarified. Implications to the one-bubble open inflation scenario are also discussed.Comment: 26 pages, 1 figure, revtex. submitted to Phys. Rev. D1

Changing Frequency Separation of Kilohertz Quasi-Periodic Oscillations in the Sonic-Point Beat-Frequency Model

Previous work on the sonic-point beat-frequency (SPBF) model of the kilohertz quasi-periodic oscillations (QPOs) observed in the X-ray flux from neutron stars in low-mass binary systems has shown that it naturally explains many properties of these QPOs. These include the existence of just two principal QPOs in a given source, the commensurability of the frequency separation \Dnu\ of the two kilohertz QPOs and the spin frequency \nus inferred from burst oscillations, and the high frequencies, coherence, and amplitudes of these QPOs. Here we show that the SPBF model predicts that \Dnu is less than but close to \nus, consistent with the observed differences between \Dnu and \nus. It also explains naturally the decrease in \Dnu with increasing QPO frequency seen in some sources and the plateau in the QPO frequency--X-ray flux observed in 4U 1820-30. The model fits well the QPO frequency behavior observed in Sco X-1, 4U 1608-52, 4U 1728-34, and 4U 1820-30 (chisqdof = 0.4-2.1), giving masses ranging from 1.59 to 2.0 Msun and spin rates ranging from 279 to 364 Hz. In the SPBF model, the kilohertz QPOs are effects of strong-field gravity. Thus, if the model is validated, the kilohertz QPOs can be used not only to determine the properties of neutron stars but also to explore quantitatively general relativistic effects in the strong-field regime.Comment: 4 pages, 2 figures, LaTeX, uses emulateapj; submitted to ApJ Letter

Covariant perturbations of domain walls in curved spacetime

A manifestly covariant equation is derived to describe the perturbations in a domain wall on a given background spacetime. This generalizes recent work on domain walls in Minkowski space and introduces a framework for examining the stability of relativistic bubbles in curved spacetimes.Comment: 15 pages,ICN-UNAM-93-0

Optimization of Monte-Carlo calculations of the effective potential

We study Monte Carlo calculations of the effective potential for a scalar field theory using three techniques. One of these is a new method proposed and tested for the first time. In each case we extract the renormalised quantities of the theory. The system studied in our calculations is a one component $\phi^4$ model in two dimensions. We apply these methods to both the weak and strong coupling regime. In the weak coupling regime we compare our results for the renormalised quantities with those obtained from two-loop lattice perturbation theory. Our results are verified in the strong coupling regime through comparison with the strong coupling expansion. We conclude that effective potential methods, when suitably chosen, can be accurate tools in calculations of the renormalised parameters of scalar field theories.Comment: 26 pages of LaTeX, uses psfig.sty with 6 figures. Entire manuscript available as a postscript file via WWW at http://www.physics.adelaide.edu.au/theory/papers/ADP-97-13.T250-abs.html or via anonymous ftp at ftp://bragg.physics.adelaide.edu.au/pub/theory/ADP-97-13.T250.p

Six-body Light-Front Tamm-Dancoff approximation and wave functions for the massive Schwinger model

The spectrum of the massive Schwinger model in the strong coupling region is obtained by using the light-front Tamm-Dancoff (LFTD) approximation up to including six-body states. We numerically confirm that the two-meson bound state has a negligibly small six-body component. Emphasis is on the usefulness of the information about states (wave functions). It is used for identifying the three-meson bound state among the states below the three-meson threshold. We also show that the two-meson bound state is well described by the wave function of the relative motion.Comment: 19 pages, RevTeX, 7 figures are available upon request; Minor errors have been corrected; Final version to appear in Phys.Rev.

Critical Ultrasonics Near the Superfluid Transition : Finite Size Effects

The suppression of order parameter fluctuations at the boundaries causes the ultrasonic attenuation near the superfluid transition to be lowered below the bulk value. We calculate explicitly the first deviation from the bulk value for temperatures above the lambda point. This deviation is significantly larger than for static quantities like the thermodynamic specific heat or other transport properties like the thermal conductivity. This makes ultrasonics a very effective probe for finite size effects.Comment: 10 pages (LaTeX), 1 figure (PostScript

A New Basis Function Approach to 't Hooft-Bergknoff-Eller Equations

We analytically and numerically investigate the 't Hooft-Bergknoff-Eller equations, the lowest order mesonic Light-Front Tamm-Dancoff equations for U(N_C) and SU(N_C) gauge theories. We find the wavefunction can be well approximated by new basis functions and obtain an analytic formula for the mass of the lightest bound state. Its value is consistent with the precedent results.Comment: 16 pages, 3 figure