2018/11/27 by Ogilvie, Michael C., Medina, Leandro
#FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High Energy Physics - Theory (hep-th)
paper · doi:10.48550/arxiv.1811.11112
Many scalar field theory models with complex actions are invariant under the antilinear (PT) symmetry operation L∗(-χ)=L(χ). Models in this class include the iϕ3 model, the Bose gas at finite density and Polyakov loop spin models at finite density. This symmetry may be used to obtain a dual representation where weights in the functional integral are real but not necessarily positive. For a subclass of models satisfying a dual positive weight condition, the partition function is manifestly positive. The sign problem is eliminated; such models are easily simulated by a simple local algorithm in any number of dimensions. Simulations of models in this subclass show a rich set of behaviors. Propagators may exhibit damped oscillations, indicating a clear violation of spectral positivity. Pattern formation may also occur, with both stripe and bubble morphologies possible. The existence of a positive representation is constrained by Lee-Yang zeros: a positive representation cannot exist everywhere in the neighborhood of such a zero. Simulation results raise the possibility that pattern-forming behavior may occur in finite density QCD in the vicinity of the critical line.