Venue: Physics Building, Max-von-Laue-Str. 1, Seminar
Room PHYS 2.116
Time: Thursday, July 07, 4:30 pm (s.t.)
Contact: hees@fias.uni-frankfurt.de
The 2d
O(3) $\sigma$ model shares asymptotic freedom, mass generation and other
nonperturbative features with 4d QCD. Likewise, a sign problem at
nonzero chemical potential hampers numerical simulations of its
thermodynamics. I demonstrate how mapping the corresponding lattice
fields to dual degrees of freedom solves the sign problem. At small
volume and temperatures this can be used to extract the phase shifts
governing the particles' interaction. Moreover, I discuss the phase
diagram of this model including a quantum phase transition and a
comparison to a solvable model.