Is the Kaniadakis deformation of holographic dark energy detectable? A non-flat analysis with DESI DR2, cosmic chronometers and Pantheon+SH0ES

Kaniadakis entropy deforms the horizon entropy through a single parameter $K$, and the holographic dark energy built on it (KHDE) reduces to the standard model as $K\to0$. We ask whether current data can detect this deformation when spatial curvature is free and no cosmic-microwave-background calibration is assumed. Combining Pantheon+SH0ES supernovae, with the absolute magnitude fitted against the Cepheid calibrators, 32 cosmic-chronometer measurements of $H(z)$ and DESI DR2 baryon acoustic oscillations with a free sound horizon, we find that non-flat KHDE fits the data as well as flat $Λ$CDM ($Δχ^2=-2.1$ for three additional parameters) but leaves $K$ unconstrained: the profile $χ^2$ changes by only $0.47$ between $K=0$ and its best value, and the bound $K<0.67$ (95%) reflects the validity domain of the model rather than the data. Information criteria therefore prefer $Λ$CDM ($Δ\mathrm{AIC}=+3.9$, $Δ\mathrm{BIC}=+20.2$). The joint fit gives $Ω_{k0}=0.012\pm0.045$, three times tighter than supernovae alone, $H_0=72.04\pm0.85\,\mathrm{km\,s^{-1}\,Mpc^{-1}}$ and $r_d=139.34\pm1.76\,\mathrm{Mpc}$; chronometers and DESI alone prefer $H_0=68.17\pm1.93$, $2.4σ$ below the supernova value. In the fitted model, acceleration begins at $z_t=0.66\pm0.03$; a model-independent neural-network reconstruction of $H(z)$ from the chronometers gives a present-day deceleration parameter $q_0=-0.46\pm0.14$, consistent with the model. We also identify three analysis requirements which, if ignored, make the deformation numerically invisible, underestimate the $H_0$ uncertainty fourfold, or spuriously reject the model.

Source: arXiv:2610.26883v1 - http://arxiv.org/abs/2610.26883v1 PDF: https://arxiv.org/pdf/2610.26883v1 Original Link: http://arxiv.org/abs/2610.26883v1