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Return of Harrison-Zeldovich spectrum in light of recent cosmological tensions

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arxiv 2210.06125 v2 pith:LKU45OAZ submitted 2022-10-12 astro-ph.CO gr-qchep-th

Return of Harrison-Zeldovich spectrum in light of recent cosmological tensions

classification astro-ph.CO gr-qchep-th
keywords harrison-zeldovichlevellightrecentreturnsigmasignificancespectrum
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved
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The spectral index $n_s$ of scalar perturbation is the significant initial condition set by inflation theory for our observable Universe. According to Planck results, current constraint is $n_s = 0.965\pm 0.004$, while an exact scale-invaiant Harrison-Zeldovich spectrum, i.e. $n_s=1$, has been ruled out at $8.4\sigma$ significance level. However, it is well-known that the standard $\Lambda$CDM model is suffering from the Hubble tension, which is at $\sim 5\sigma$ significance level. This inconsistency likely indicates that the comoving sound horizon at last scattering surface is actually lower than expected, which so seems to be calling for the return of $n_s=1$. Here, in light of recent observations we find strong evidence for a $n_s=1$ Universe. And we show that if so, it would be confirmed conclusively by CMB-S4 experiment.

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Forward citations

Cited by 6 Pith papers

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score.

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  2. Harrison-Zeldovich attractor: From Planck to ACT results

    astro-ph.CO 2025-10 conditional novelty 6.0

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  3. Running into tension: primordial black holes from ultra-slow-roll inflation, spectral running, and the Hubble tension

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  4. Intertwined Constraints in Extended Cosmologies: Dark Energy, Curvature, Neutrinos, and Inflation

    astro-ph.CO 2026-07 unverdicted novelty 4.0

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  5. The Hubble tension: A decade review

    astro-ph.CO 2026-06 conditional novelty 3.0

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