7,081 research outputs found
On the emergence of gauge structures and generalized spin when quantizing on a coset space
It has been known for some time that there are many inequivalent
quantizations possible when the configuration space of a system is a coset
space G/H. Viewing this classical system as a constrained system on the group
G, we show that these inequivalent quantizations can be recovered from a
generalization of Dirac's approach to the quantization of such a constrained
system within which the classical first class constraints (generating the
H-action on G) are allowed to become anomalous (second class) when quantizing.
The resulting quantum theories are characterized by the emergence of a
Yang-Mills connection, with quantized couplings, and new 'spin' degrees of
{}freedom. Various applications of this procedure are presented in detail:
including a new account of how spin can be described within a path-integral
formalism, and how on S^4 chiral spin degrees of {}freedom emerge, coupled to a
BPST instanton.Comment: 64 pages, plain TeX, DIAS-STP-93-1
Impact of Repair Joints in Fencing Wire on Data Communications: How to Receive Radio and Block Data using No. 8 Wire
Modern electric fences have remote controls and remote monitors that communicate with the energizer through the active fence wire. This manuscript looks at the impact of repair joints on the data communications between energizer and remotes. We report measurements of nonlinear rust-induced characteristics in joints and we draw conclusions about their effects in the context of an electric fence carrying data communications signals. We furthermore demonstrate how their nonlinear characteristics can cause mixing and detection effects that could account for radio reception
Stability, creation and annihilation of charges in gauge theories
We show how to construct physical, minimal energy states for systems of
static and moving charges. These states are manifestly gauge invariant. For
charge-anticharge systems we also construct states in which the gauge fields
are restricted to a finite volume around the location of the matter fields.
Although this is an excited state, it is not singular, unlike all previous
finite volume descriptions. We use our states to model the processes of pair
creation and annihilation.Comment: Six EPS figures. Version 2: minor typos correcte
A New Symmetry for QED
We demonstrate that QED exhibits a previously unobserved symmetry. Some
consequences are discussed.Comment: 9 pages, MZ-TH/93-02, DIAS-STP-93-0
Charges in Gauge Theories
Recent progress in the construction of both electric, coloured and magnetic
charges in gauge theories will be presented. The topological properties of the
charged sectors will be highlighted as well as the applications of this work to
confinement and infrared dynamics.Comment: This is a contribution to the Proc. of the O'Raifeartaigh Symposium
on Non-Perturbative and Symmetry Methods in Field Theory (June 2006,
Budapest, Hungary), published in SIGMA (Symmetry, Integrability and Geometry:
Methods and Applications) at http://www.emis.de/journals/SIGMA
The Colour of Quarks
It is shown that colour can only be defined on gauge invariant states. Since
the ability to associate colour with constituent quarks is an integral part of
the constituent quark model, this means that, if we want to extract constituent
quarks from QCD, we need to dress Lagrangian quarks with gluons so that the
result is gauge invariant. We further prove that gauge fixings can be used to
construct such dressings. Gauge invariant dressed quark states are presented
and a direct approach to the interquark potential is discussed. Some further
aspects of dressing quarks are briefly discussed.Comment: Extended version, to appear in Phys. Lett B., 7 pages, Te
Efficacy of a four-week uphill sprint training intervention in field hockey players
Current evidence increasingly suggests that very short, supra-maximal bouts of exercise can have significant health and performance benefits. The majority of research conducted in the area however, uses laboratory-based protocols, which can lack ecological validity. The purpose of this study was to examine the effects of a high intensity sprint-training programme on hockey related performance measures. 14 semi-professional hockey players completed either a 4-week high intensity training (HIT) intervention, consisting of a total of six sessions HIT, which progressively increased in volume (n=7), or followed their normal training programme (Con; n=7). Straight-line sprint speed with and without a hockey stick and ball, and slalom sprint speed, with and without a hockey stick and ball were used as performance indicators. Maximal sprint speed over 22.9m was also assessed. Upon completion of the four-week intervention, straight-line sprint speed improved significantly in the HIT group (~3%), with no change in performance for the Con group. Slalom sprint speed, both with and without a hockey ball was not significantly different following the training programme in either group. Maximal sprint speed improved significantly (12.1%) in the HIT group, but there was no significant performance change in the Con group. The findings of this study indicate that a short period of HIT can significantly improve hockey related performance measures, and could be beneficial to athletes and coaches in field settings
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