2,630 research outputs found
The Yang-Mills vacuum in Coulomb gauge
The Yang-Mills Schr\"odinger equation is solved in Coulomb gauge for the
vacuum by the variational principle using an ansatz for the wave functional,
which is strongly peaked at the Gribov horizon. We find an infrared suppressed
gluon propagator, an infrared singular ghost propagator and an almost linearly
rising confinement potential. Using these solutions we calculate the electric
field of static color charge distributions relevant for mesons and baryons.Comment: 4 pages, 5 figures, Proceedings ``Confinement Conference Sardinia
2004'
Hamiltonian approach to Yang-Mills theory in Coulomb gauge
Recent results obtained within the Hamiltonian approach to continuum
Yang-Mills theory in Coulomb gauge are reviewed.Comment: 7 pages, 2 figures, to appear in the ``Quark Confinement and the
hadron spectrum VII'' (Portugal 2006) conference proceeding
Confining Solution of the Dyson-Schwinger Equations in Coulomb Gauge
The Dyson-Schwinger equations arising from minimizing the vacuum energy
density in the Hamiltonian approach to Yang-Mills theory in Coulomb gauge are
solved numerically. A new solution is presented which gives rise to a strictly
linearly rising static quark potential and whose existence was previously
observed in the infrared analysis of the Dyson-Schwinger equations. For the new
solution we also present the static quark potential and calculate the running
coupling constant from the ghost-gluon vertex.Comment: 9 pages, 3 figures, references added
RF-dressed Rydberg atoms in hollow-core fibres
The giant electro-optical response of Rydberg atoms manifests itself in the
emergence of sidebands in the Rydberg excitation spectrum if the atom is
exposed to a radio-frequency (RF) electric field. Here we report on the study
of RF-dressed Rydberg atoms inside hollow-core photonic crystal fibres
(HC-PCF), a system that enables the use of low modulation voltages and offers
the prospect of miniaturised vapour-based electro-optical devices. Narrow
spectroscopic features caused by the RF field are observed for modulation
frequencies up to 500 MHz.This is the author accepted manuscript. It is currently under an indefinite embargo pending publication by the Institute of Physics
Institutional Effects in a Simple Model of Educational Production
This paper presents a model of educational production that tries to make sense of recent evidence on effects of institutional arrangements on student performance. In a simple principal-agent framework, students choose their learning effort to maximize their net benefits, while the government chooses educational spending to maximize its net benefits. In the jointly determined equilibrium, schooling quality is shown to depend on several institutionally determined parameters. The impact on student performance of institutions such as central examinations, centralization versus school autonomy, teachers\u27 influence, parental influence, and competition from private schools is analyzed. Furthermore, the model can rationalize why positive resource effects may be lacking in educational production
Heat-kernel expansion and counterterms of the Faddeev-Popov determinant in Coulomb and Landau gauge
The Faddeev-Popov determinant of Landau gauge in d dimensions and Coulomb
gauge in d+1 dimensions is calculated in the heat-kernel expansion up to
next-to-leading order. The UV-divergent parts in d=3,4 are isolated and the
counterterms required for a non-perturbative treatment of the Faddeev-Popov
determinant are determined.Comment: 7 page
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