Comment on "Families of Particles with Different Masses in PT-Symmetric Quantum Field Theory" [arXiv:1002.3253]

TL;DR

This paper critically analyzes a proposed quantum field theory claiming to explain particle families without group structures, demonstrating through variational calculations that the theory favors a Hermitian vacuum and does not support the existence of multiple particle families.

Contribution

It provides a variational analysis showing the original theory's vacuum structure favors Hermiticity and does not support multiple particle families as claimed.

Findings

The vacuum with unbroken Z2 symmetry has lower energy.

The theory is Hermitian in the preferred vacuum.

No evidence for multiple particle families in the proposed model.

Abstract

In a recent letter by Carl M. Bender and S. P. Klevansky [arXiv:1002.3253] an elementary field theory is proposed where the authors claimed that it can account for the existence of family of particles without any employment of group structures. In this work, we relied on the fact that the Dyson-Schwinger equations used by the authors stem from a variational principle and tried to reproduce their results by a mere variational algorithm. We were able to reproduce exactly their results by the employment of two different variational calculations of the vacuum energy in the proposed theory. We showed that the two vacuum solutions obtained by the authors of the commented letter correspond to two non-degenerate vacuum energies except for the $d=0$ space-time dimensions where the vacuum states are degenerate. Since any variational calculation of the vacuum energy should be higher than the true (exact) vacuum energy, the most accurate result will correspond to the vacuum that lowers the vacuum energy. We showed that the vacuum with unbroken $Z_{2}$ symmetry has lower energy than the vacuum with broken $Z_{2}$ symmetry. Accordingly, the theory will prefer to live with the vacuum of unbroken $Z_{2}$ symmetry in which the proposed theory is Hermitian. Thus the proposed theory neither has a preferred non-Hermitian representation nor it describes a family of particles as claimed by the authors of the commented work.