Two-parametric PT-symmetric quartic family
  We describe a parametrization of the real spectral locus of the two-parametric family of PT-symmetric quartic oscillators. For this family, we find a parameter region where all eigenvalues are real, extending the results of Dorey, Dunning, Tateo and Shin. 
Alexandre Eremenko and Andrei Gabrielov
math-ph math.CV math.MP