Reflection positivity in a higher-derivative model with physical bound states of ghosts

Asorey, Manuel (Universidad de Zaragoza) ; Krein, Gastão ; Pardina, Miguel (Universidad de Zaragoza) ; Shapiro, Ilya L.

Resumen: The inclusion of higher derivatives is a necessary condition for a renormalizable or superrenormalizable local theory of quantum gravity. On the other hand, higher derivatives lead to classical instabilities and a loss of unitarity at the quantum level. A standard way to detect such issues is by examining the reflection positivity condition and the existence of a Källén-Lehmann spectral representation for the two-point function. We demonstrate that these requirements for a consistent quantum theory are satisfied in a theory we have recently proposed. This theory is based on a six-derivative scalar field action featuring a pair of complex-mass ghost fields that form a bound state. Our results support the interpretation that physical observables can emerge from ghost dynamics in a consistent and unitary framework.

Idioma: Inglés

DOI: 10.1007/JHEP02(2026)020

Año: 2026

Publicado en: Journal of High Energy Physics 2026, 20 (2026), [14 pp.]
ISSN: 1126-6708

Financiación: info:eu-repo/grantAgreement/ES/DGA-FSE/E21-17R
Financiación: info:eu-repo/grantAgreement/ES/MICINN/PGC2022-126078NB-C21

Tipo y forma: Artículo (Versión definitiva)

Área (Departamento): Área Física Teórica (Dpto. Física Teórica)