2,510 research outputs found
Noncommutative Quantum Field Theory: A Confrontation of Symmetries
The concept of a noncommutative field is formulated based on the interplay
between twisted Poincar\'e symmetry and residual symmetry of the Lorentz group.
Various general dynamical results supporting this construction, such as the
light-wedge causality condition and the integrability condition for
Tomonaga-Schwinger equation, are presented. Based on this analysis, the claim
of the identity between commutative QFT and noncommutative QFT with twisted
Poincar\'e symmetry is refuted.Comment: 20 page
The implications from CANGAROO-III observations of TeV blazar PKS 2155-304
We have observed the high-frequency-peaked BL Lacertae object PKS2155-304 in
2004, 2005 and 2006 with the CANGAROO-III imaging atmospheric Cherenkov
telescope, and have detected a signal above 660 GeV at the 4.8/sigma level
during the 2006 outburst period. Intranight flux variability on time scale of
half an hour is observed. From this variability time scale, the size of the TeV
gamma-ray emission region is restricted to 5x10^13\delta cm, and the super
massive black hole mass is estimated to be less than 1.9x10^8\delta M_{Solar},
where \delta is the beaming factor. The differential energy spectrum is
obtained, and an upper limit of the extragalactic infrared background light
(EBL) flux is derived under some assumption. We also fit a synchrotron self
Compton (SSC) model to the spectral energy distribution (SED) and derive the
beaming factor and magnetic field strength.Comment: 4 pages, 5 figures, proceedings of the "4th Heidelberg International
Symposium on High Energy Gamma-Ray Astronomy" July 7-11, 2008, Heidelberg,
German
An Interpretation of Noncommutative Field Theory in Terms of a Quantum Shift
Noncommutative coordinates are decomposed into a sum of geometrical ones and
a universal quantum shift operator. With the help of this operator, the mapping
of a commutative field theory into a noncommutative field theory (NCFT) is
introduced. A general measure for the Lorentz-invariance violation in NCFT is
also derived.Comment: 16 page
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