000152174 001__ 152174
000152174 005__ 20251017144550.0
000152174 0247_ $$2doi$$a10.1103/PhysRevD.111.064020
000152174 0248_ $$2sideral$$a143445
000152174 037__ $$aART-2025-143445
000152174 041__ $$aeng
000152174 100__ $$0(orcid)0000-0003-3669-6241$$aAsorey, Manuel$$uUniversidad de Zaragoza
000152174 245__ $$aStability of cosmological singularity-free solutions in quadratic gravity
000152174 260__ $$c2025
000152174 5203_ $$aWe introduce a large family of homogeneous and isotropic cosmological solutions in quadratic gravity which are singularity-free at early and late times. This kind of smooth solutions only emerge beyond the nonstandard de Sitter branch 3 <, and being the couplings of the 2 and −2 terms. We have analyzed the stability of these singularity-free solutions by computing the second-order variation of the action. We show that the expected instability is similar to that of the standard Λ Cold Dark Matter (Λ CDM) scenario. Thus, they provide cosmological background scenarios as legitimate as that of the Standard Model. The complete analysis shows that a singular big bang scenario can emerge from a singularity-free cosmological scenario when the parameters of the theory are slightly modified, which provides a bridge between the two very different cosmological scenarios with similar instabilities.
000152174 536__ $$9info:eu-repo/grantAgreement/ES/DGA-FSE/E21-17R$$9info:eu-repo/grantAgreement/ES/DGIID-DGA/2020-E21-17R$$9info:eu-repo/grantAgreement/ES/MICINN/PGC2022-126078NB-C21$$9info:eu-repo/grantAgreement/ES/NextGenerationEU/PRTR
000152174 540__ $$9info:eu-repo/semantics/closedAccess$$aby$$uhttps://creativecommons.org/licenses/by/4.0/deed.es
000152174 655_4 $$ainfo:eu-repo/semantics/article$$vinfo:eu-repo/semantics/acceptedVersion
000152174 700__ $$aEzquerro, Fernando$$uUniversidad de Zaragoza
000152174 700__ $$aPardina, Miguel$$uUniversidad de Zaragoza
000152174 7102_ $$12004$$2X$$aUniversidad de Zaragoza$$bDpto. Física Teórica$$cÁrea Administrativa
000152174 7102_ $$12004$$2405$$aUniversidad de Zaragoza$$bDpto. Física Teórica$$cÁrea Física Teórica
000152174 773__ $$g111, 6 (2025), 9 pp.$$pPhys. rev. D$$tPhysical Review D$$x2470-0010
000152174 8564_ $$s1235357$$uhttps://zaguan.unizar.es/record/152174/files/texto_completo.pdf$$yPostprint
000152174 8564_ $$s2841556$$uhttps://zaguan.unizar.es/record/152174/files/texto_completo.jpg?subformat=icon$$xicon$$yPostprint
000152174 909CO $$ooai:zaguan.unizar.es:152174$$particulos$$pdriver
000152174 951__ $$a2025-10-17-14:11:35
000152174 980__ $$aARTICLE