Galilean symmetry in noncommutative field theory
Résumé
When the interaction potential is suitably reordered, the Moyal field theory admits two types of Galilean symmetries, namely the conventional mass-parameter-centrally-extended one with commuting boosts, but also the two-fold centrally extended ``exotic\'\' Galilean symmetry, where the commutator of the boosts yields the noncommutative parameter. In the free case, one gets an ``exotic\'\' two-parameter central extension of the Schroedinger group. The conformal symmetry is, however, broken by the interaction.