Amplitude prescriptions in field theories with complex poles

Fuente: arXiv
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Main Authors: Anselmi, Damiano, Briscese, Fabio, Calcagni, Gianluca, Modesto, Leonardo
Format: Preprint
Published: 2025
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author Anselmi, Damiano
Briscese, Fabio
Calcagni, Gianluca
Modesto, Leonardo
author_facet Anselmi, Damiano
Briscese, Fabio
Calcagni, Gianluca
Modesto, Leonardo
contents In the context of field theories with complex poles, we scrutinize four inequivalent ways of defining the scattering amplitudes, each forfeiting one or more tenets of standard quantum field theory while preserving the others: (i) a textbook Wick rotation by analytic continuation of the external momenta from Euclidean to Lorentzian signature (no optical theorem), (ii) the Lee--Wick--Nakanishi prescription, integrating along a certain contour in the complex energy plane (no Lorentz invariance), (iiii) the fakeon prescription, where, in addition, spatial momenta are integrated on a complex path defined by the locus of singularities of the loop integrand (no analyticity of the amplitude) and (iv) to work directly on Minkowski spacetime, which violates the optical theorem and also bars power-counting renormalizability. In general, mixed Euclidean-Lorentzian prescriptions for internal and external momenta in loop integrals break Lorentz invariance, regardless of the type of masses involved. We conclude that, of the above four options, only the fakeon prescription is physically viable and can have applications to quantum gravity.
format Preprint
id arxiv_https___arxiv_org_abs_2503_01841
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Amplitude prescriptions in field theories with complex poles
Anselmi, Damiano
Briscese, Fabio
Calcagni, Gianluca
Modesto, Leonardo
High Energy Physics - Theory
General Relativity and Quantum Cosmology
In the context of field theories with complex poles, we scrutinize four inequivalent ways of defining the scattering amplitudes, each forfeiting one or more tenets of standard quantum field theory while preserving the others: (i) a textbook Wick rotation by analytic continuation of the external momenta from Euclidean to Lorentzian signature (no optical theorem), (ii) the Lee--Wick--Nakanishi prescription, integrating along a certain contour in the complex energy plane (no Lorentz invariance), (iiii) the fakeon prescription, where, in addition, spatial momenta are integrated on a complex path defined by the locus of singularities of the loop integrand (no analyticity of the amplitude) and (iv) to work directly on Minkowski spacetime, which violates the optical theorem and also bars power-counting renormalizability. In general, mixed Euclidean-Lorentzian prescriptions for internal and external momenta in loop integrals break Lorentz invariance, regardless of the type of masses involved. We conclude that, of the above four options, only the fakeon prescription is physically viable and can have applications to quantum gravity.
title Amplitude prescriptions in field theories with complex poles
topic High Energy Physics - Theory
General Relativity and Quantum Cosmology
url https://arxiv.org/abs/2503.01841