000070256 001__ 70256 000070256 005__ 20200117213749.0 000070256 0247_ $$2doi$$a10.3390/galaxies6010023 000070256 0248_ $$2sideral$$a105344 000070256 037__ $$aART-2018-105344 000070256 041__ $$aeng 000070256 100__ $$0(orcid)0000-0003-3669-6241$$aAsorey, M.$$uUniversidad de Zaragoza 000070256 245__ $$aUnitary issues in some higher derivative field theories 000070256 260__ $$c2018 000070256 5060_ $$aAccess copy available to the general public$$fUnrestricted 000070256 5203_ $$aWe analyze the unitarity properties of higher derivative quantum field theories which are free of ghosts and ultraviolet singularities. We point out that in spite of the absence of ghosts most of these theories are not unitary. This result confirms the difficulties of finding a consistent quantum field theory of quantum gravity. 000070256 536__ $$9info:eu-repo/grantAgreement/EUR/COST/MP1405-QSPACE$$9info:eu-repo/grantAgreement/ES/DGA/E24-2$$9info:eu-repo/grantAgreement/ES/MINECO/FPA2015-65745-P 000070256 540__ $$9info:eu-repo/semantics/openAccess$$aby$$uhttp://creativecommons.org/licenses/by/3.0/es/ 000070256 592__ $$a0.591$$b2018 000070256 593__ $$aAstronomy and Astrophysics$$c2018$$dQ3 000070256 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/publishedVersion 000070256 700__ $$aRachwal, L. 000070256 700__ $$aShapiro, I. 000070256 7102_ $$12004$$2405$$aUniversidad de Zaragoza$$bDpto. Física Teórica$$cÁrea Física Teórica 000070256 773__ $$g6, 1 (2018), 23 [7 pp]$$pGalaxies$$tGalaxies$$x2075-4434 000070256 8564_ $$s232654$$uhttps://zaguan.unizar.es/record/70256/files/texto_completo.pdf$$yVersión publicada 000070256 8564_ $$s97466$$uhttps://zaguan.unizar.es/record/70256/files/texto_completo.jpg?subformat=icon$$xicon$$yVersión publicada 000070256 909CO $$ooai:zaguan.unizar.es:70256$$particulos$$pdriver 000070256 951__ $$a2020-01-17-21:31:30 000070256 980__ $$aARTICLE