1,545 research outputs found
Gauge invariance, background fields and modified Ward identities
In this talk the gauge symmetry for Wilsonian flows in pure Yang-Mills
theories is discussed. The background field formalism is used for the
construction of a gauge invariant effective action. The symmetries of the
effective action under gauge transformations for both the gauge field and the
auxiliary background field are separately evaluated. Modified Ward-Takahashi
and background field identities are used in my study. Finally it is shown how
the symmetry properties of the full theory are restored in the limit where the
cut-off is removed.Comment: 6 pages, to appear in the Proceedings of the 2nd Conference on the
Exact Renormalization Group, Rome 200
Convexity of the effective action from functional flows
We show that convexity of the effective action follows from its functional
flow equation. Our analysis is based on a new, spectral representation. The
results are relevant for the study of physical instabilities. We also derive
constraints for convexity-preserving regulators within general truncation
schemes including proper-time flows, and bounds for infrared anomalous
dimensions of propagators.Comment: 4 pages, 3 figure
The Epistemological Justification of Intercollegiate Advisement Programs for Student-Athletes or Why We Do What We Do in the First Place!
This is a short piece on the purpose behind why advisors support athletes at Union County College
Method and apparatus for receiving and tracking phase modulated signals
An apparatus and technique are described for receiving and tracking analog or digital phase modulated signals from 0 deg to 360 deg phase shift. In order to track a signal with many phases, a detector discerns the phase modulation of the incoming signal and a phase shifter generates a negative phase shift opposite in angle to the detected phase angle. This produces a converted series sideband component barrier signal. The residual carrier signal and the converted series sideband component carrier are added together to produce a tracking carrier signal. The tracking carrier signal is multiplied with the output from a voltage controlled oscillator in the tracking loop to obtain an error signal which drives the voltage controlled oscillator and tracks the incoming signal frequency. The technique is less susceptible to carrier interference which may degrade tracking and tracking may be performed at lower signal to noise ratios and for lower input signal power levels
Shuttle payload S-band communications system
The Shuttle payload S-band communications system design, operational capabilities, and performance are described in detail. System design requirements, overall system and configuration and operation, and laboratory/flight test results are presented. Payload communications requirements development is discussed in terms of evolvement of requirements as well as the resulting technical challenges encountered in meeting the initial requirements. Initial design approaches are described along with cost-saving initiatives that subsequently had to be made. The resulting system implementation that was finally adopted is presented along with a functional description of the system operation. A description of system test results, problems encountered, how the problems were solved, and the system flight experience to date is presented. Finally, a summary of the advancements made and the lessons learned is discussed
On Gauge Invariance and Ward Identities for the Wilsonian Renormalisation Group
We investigate non-Abelian gauge theories within a Wilsonian Renormalisation
Group approach. The cut-off term inherent in this approach leads to a modified
Ward identity (mWI). It is shown that this mWI is compatible with the flow and
that the full effective action satisfies the usual Ward identity (WI). The
universal 1-loop beta-function is derived within this approach and the
extension to the 2-loop level is briefly outlined.Comment: 4 pages, latex, talk presented by J. M. Pawlowski at QCD 98,
Montpellier, July 2-8, 1998; to be published in Nucl. Phys. B (Proc. Suppl.),
reference update
Signatures of confinement in Landau gauge QCD
We summarise an analysis of the infrared regime of Landau gauge QCD by means
of a flow equation approach. The infrared behaviour of gluon and ghost
propagators is evaluated. The results provide further evidence for the
Kugo-Ojima confinement scenario. We also discuss their relation to results
obtained with other functional methods as well as the lattice.Comment: 3 pages, talk given by JMP at 6th Conference on Quark Confinement and
the Hadron Spectrum, Villasimius, Sardinia, Italy, 21-25 Sep 200
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