I have no idea why it took almost two weeks from submission for this preprint to be released by arXiv.
Recent discoveries, e.g., by JWST and DESI, have elevated the level of tension with inflationary ΛCDM. For example, the empirical evidence now suggests that the standard model violates at least one of the energy conditions from general relativity, which were designed to ensure that systems have positive energy, attractive gravity and non-superluminal energy flows.
In this Letter, we use a recently compiled Type Ia supernova sample to examine whether ΛCDM violates the energy conditions in the local Universe, and carry out model selection with its principal competitor, the Rh=ct universe. We derive model-independent constraints on the distance modulus based on the energy conditions and compare these with the Hubble diagram predicted by both ΛCDM and Rh=ct, using the Pantheon+ Type Ia supernova catalog.
We find that ΛCDM violates the strong energy condition over the redshift range z⊂(0,2), whereas Rh=ct satisfies all four energy constraints. At the same time, Rh=ct is favored by these data over ΛCDM with a likelihood of ∼89.5% versus ∼10.5%. The Rh=ct model without inflation is strongly favored by the Type Ia supernova data over the currrent standard model, while simultaneously adhering to the general relativistic energy conditions at both high and low redshifts.
Namit Chandak, Fulvio Melia, Junjie Wei, "Model selection with the Pantheon+ Type Ia SN sample" arXiv:2602.15047 (February 5, 2026) (4 pages, accepted for publication in A&A Letters).
If I asked a passel of astrophysics post-grads what the principle competitor to Lambda CDM was would they answer Rh=ct?
ReplyDeleteThis preprint is in General Physics - arxiv's version of vixra - rather than astro-ph, so the two week delay is most likely because of the moderation process that relegated the paper to General.
ReplyDeleteThis paper makes numerous claims regarding the superiority of Fulvio Melia's "R_h=ct" model. Just as Guy probably suspects, the view that Rh=ct is the main rival to LambdaCDM is only held by fans of Rh=ct.
I have studied it a bit in the past - Marni Sheppeard was mildly interested in it. This discussion with Claude identifies some problems. Basically the implied cosmic equation of state requires some peculiar form of matter that is never specified.
https://claude.ai/share/34693e23-7819-484e-b998-493321fc0f23
Also, in this short paper, Melia and coauthors make much of the fact that inflation and accelerated expansion require a violation of the "strong energy condition". But they don't make the case that this is inherently problematic. Violations of energy conditions do occur within QFT, e.g. the Casimir effect.
On the other hand, it's ironic that the string theorist Cumrun Vafa thinks that inflation and dark energy are both impossible in string theory! There is no consensus on this, but certainly the construction of De Sitter space within string theory (which is the geometry implied in both cases) has proved to be full of pitfalls. It would be ironic if Melia's outlook turns out to make the most sense within a stringy framework.
@Mitchell Thanx for the Claude link, very enlightening.
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