Scattering in pseudo-Hermitian quantum field theory and causality violation

Abstract

The non-Hermitian but $\mathcal{P}\mathcal{T}$-symmetric quantum field theories are known to have a pseudo-Hermitian interpretation. However the corresponding intertwining operator happens to be nonlocal that raises the question to what extent this nonlocality affects observable quantities. We consider the case when the intrinsic parity of the interaction terms is determined by degree of coupling constant. We show that the perturbative S-matrix of the equivalent Hermitian description can be easily obtained from the perturbative S-matrix of the non-Hermitian model. Namely, the first order vanishes whereas the second order is given by the real part of the second order T-matrix of the non-Hermitian model. We compute directly the 2-point and 4-point correlation functions in the equivalent Hermitian model for the $i{\varphi }^3$ model and find the results consistent with this relation. The 1-loop correction to the mass happens to be real reflecting the disappearance of 2-body decays. However the 2 to 2 scattering amplitude obtained using LSZ formula has poles taken in principal value which implies the violation of the causality.

arXiv comment27 pages; added new references and new concluding remarks

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Cited by in corpus (3)

• Spectral Noncommutative Geometry, Standard Model and all that
• $\mathcal{P}\mathcal{T}$-symmetric quantum field theory on the noncommutative spacetime
• Remark on the synergy between the heat kernel techniques and the parity anomaly