Scattering in pseudo-Hermitian quantum field theory and causality violation

Oleg O. Novikov (Saint Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia)

The non-Hermitian but PT-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 iϕ3 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.

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  "abstracts": [
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      "value": "The non-Hermitian but <math><mrow><mi>P</mi><mi>T</mi></mrow></math>-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 <math><mi>i</mi><msup><mi>\u03d5</mi><mn>3</mn></msup></math> 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."
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Published on:
18 March 2019
Publisher:
APS
Published in:
Physical Review D , Volume 99 (2019)
Issue 6
DOI:
https://doi.org/10.1103/PhysRevD.99.065008
arXiv:
1901.05414
Copyrights:
Published by the American Physical Society
Licence:
CC-BY-4.0

Fulltext files: