Noncommutativity VS. Transversality in QED in a Strong Magnetic Field
Abstract
Quantum electrodynamics (QED) in a strong constant magnetic field is investigated from the viewpoint of its connection with noncommutative QED. It turns out that within the lowest Landau level (LLL) approximation the 1loop contribution of fermions provides an effective action with the noncommutative U(1)_{NC} gauge symmetry. As a result, the Ward identities connected with the initial U(1) gauge symmetry are broken down in the LLL approximation. On the other hand, it is shown that the sum over the infinite number of the higher Landau levels (HLL's) is relevant despite the fact that each contribution of the HLL is suppressed. Owing to this nondecoupling phenomenon the transversality is restored in the whole effective action. The kinematic region where the LLL contribution is dominant is also discussed.
 Publication:

International Journal of Modern Physics A
 Pub Date:
 2005
 DOI:
 10.1142/S0217751X05029332
 arXiv:
 arXiv:hepth/0507083
 Bibcode:
 2005IJMPA..20.6307H
 Keywords:

 11.10.Nx;
 11.15.q;
 12.20.m;
 Noncommutative field theory;
 Gauge field theories;
 Quantum electrodynamics;
 High Energy Physics  Theory
 EPrint:
 11 pages, 2 figures