Observational viability of alternative nonlocal prescriptions

Determine the observational viability of cosmological histories generated by admissible prescriptions for the inverse d’Alembertian operator that differ from the retarded prescription and auxiliary-field initial conditions used for the path-B realization.

Background

The analysis is restricted to the path-B realization defined by a particular retarded prescription and specified auxiliary-field initial conditions. The paper emphasizes that different admissible prescriptions for the nonlocal operator can produce distinct cosmological histories. Whether those alternative realizations are compatible with observations is left unresolved.

References

Our analysis is also restricted to the path-B realization defined by the auxiliary-field initial conditions adopted here. Different admissible prescriptions for the nonlocal operator may lead to distinct cosmological histories, and their observational viability remains to be investigated.

— Nonlocal Gravity, Restricted CPL Dynamics and DESI Constraints  (2610.20720 - Amendola et al., 14 Oct 2026) in Section 5, Summary and conclusions