Spontaneous Breaking of Scale Invariance in Quantum Field Theory - Double Scaling Limit and Supersymmetry
Moshe Moshe
Technion, Haifa, Israel
Tue, Mar. 13th 2007, 11:00
Salle Claude Itzykson, Bât. 774, Orme des Merisiers
Particle masses are found to be smaller than the natural mass scale of their corresponding quantum field theories. This long lasting problem resulted in many searches for frameworks that imply the existence of mater with mass $M \ll \Lambda$. In certain conditions spontaneous breaking of scale invariance is yet another mechanism for producing massless bound states. An interesting such system will be analyzed. The phase structure of a supersymmetric, vector O(N) symmetric model in three dimensions will be presented. At zero temperature it reveals spontaneous breaking of scale invariance with no explicit breaking. When the attracting force between the massive quanta, bosons and fermions, is tuned to a certain critical value, $g_c$, one finds ${\bf massless}$ bound states, a Goldstone boson and a Goldstone fermion, associated with the spontaneous breaking of scale invariance (massless dilaton and dilatino). The effect of finite temperature on this phenomenon will be elucidated. Expectation values of the energy momentum tensor are calculated at zero and finite temperatures. The phase structure is unveiled in the limit $N \to \infty$.