Is PT-symmetric quantum theory false as a fundamental theory?

Abstract

It is shown that the toy-model-based considerations of {\em loc. cit.} (see also arXiv:1312.3395) are based on an incorrect, manifestly unphysical choice of the Hilbert space of admissible quantum states. A two-parametric family of all of the eligible correct and potentially physical Hilbert spaces of the model is then constructed. The implications of this construction are discussed. In particular, it is emphasized that contrary to the conclusions of {\em loc. cit.} there is no reason to believe that the current form of the $\mathcal{PT}$-symmetric quantum theory should be false as a fundamental theory.