Abstracts

Nikola Konjik

Angular noncommutative scalar field phenomenology in flat and curved space

In this presentation a noncommutative deformation of scalar field theory is introduced by an angular twist. The angular twist is an Abelian twist, defined by two commuting vector fields: the generator of the time translations and the generator of rotations around the z-axis. The noncommutative \phi*^4 quantum field theory is analyzed at the one-loop level and contributions to the propagator of both planar and non-planar diagrams are calculated. Using these results, UV/IR mixing is discussed. Noncommutative deformation induces a deformation of the momentum conservation law. This deformation can be expressed in terms of *-sums of momenta. The *-sum is a direct consequence of the deformed (twisted) coproduct of momenta. In the second part of this presentation a noncommutative scalar field in curved space is discussed. In particular, the dynamics of a noncommutative charged scalar field in the Reissner-Nordstrom black hole background is analyzed. Solving the scalar field equation of motion with appropriate boundary conditions, the quasinormal mode spectrum is obtained. Noncommutativity induces a splitting of spectral lines with respect to the magnetic quantum number m. Different methods are used to calculate the quasinormal mode spectrum: WKB method, continued fraction method and an analytic method. The results obtained by these methods are compared and a good qualitative agreement is shown.