Year: 2026
Type: preprint
Abstract: Nonlocal modifications of gravity provide a theoretically motivated framework in which cosmic acceleration can emerge dynamically without introducing a fundamental cosmological constant. We revisit the cosmological predictions of the Maggiore--Mancarella nonlocal $R\,\Box^{-2}R$ model, with particular emphasis on its background dynamics and observational viability in light of recent DESI baryon acoustic oscillation measurements. A key feature of the theory is its predictive character: for fixed standard cosmological parameters, each value of the nonlocal parameter determines a specific effective pair $(w_0,w_a)$, so that the model traces a restricted trajectory in the Chevallier--Polarski--Linder plane rather than spanning the full phenomenological parameter space. We construct this mapping explicitly and confront the model with observations by implementing its cosmological dynamics in a Boltzmann solver and performing a Markov chain Monte Carlo analysis using Cosmic Microwave Background, supernova, and DESI BAO data. We find that current datasets constrain the nonlocal parameter close to the $Λ$CDM limit, with no statistically significant preference for nonlocal deviations.
Source: arXiv (Cornell University)
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: New York University Abu Dhabi, Department of Science and Technology, Ministry of Science and Technology, India, Deutscher Akademischer Austauschdienst, Deutsche Forschungsgemeinschaft, Eusko Jaurlaritza, Ministerio de Ciencia e Innovación, Tamkeen, European Regional Development Fund, Agencia Estatal de Investigación, European Social Fund
Awards: G121809054, G1338257350, G1401168639, G1578893264, G1620761618, G1622782223, G1855990336, G2193687834, G2309174360, G2660406951, G2779896429, G279363373, G332510590, G3428307696, G3518538256, G4033406476, G4046441750, G410571670, G4269502044, G430777504, G451917667, G4546701545, G5255598334, G5421974903, G546199279, G5539308778, G5943232429, G5967599077, G6033112984, G6218905885, G6276773425, G6418212698, G6526081583, G6806626197, EXC 2181: STRUKTUREN: Emergenz in Natur, Mathematik und komplexen Daten, G7227535049, G8575141037, G8888022036, G8920660035, G8936613312, G897484643, G929308097, G99296377
OpenAlex ID: W7222761483