What the study found
The measured decay rate of cosmological gravitational potential was consistent with general relativity (GR), which is the standard theory of gravity. The authors also report that several one-parameter modified gravity models remained consistent with the GR case within uncertainties.
Why the authors say this matters
The study suggests that the decay rate of cosmological gravitational potential can be used to test GR on cosmological scales, helping distinguish between dark energy and modified gravity as explanations for late-time cosmic acceleration. The authors also say this approach is sensitive to gravity and immune to various astrophysical uncertainties.
What the researchers tested
The researchers used a previously measured decay rate over redshift 0.2 to 1.4, combining the DESI imaging surveys' DR9 galaxy catalog with Planck cosmic microwave background maps. They tested GR using one-parameter extensions to the standard Lambda cold dark matter (ΛCDM) cosmology and examined four modified gravity parameterizations, including a growth index form and three forms for the effective gravitational constant with the gravitational slip parameter fixed to 1.
What worked and what didn't
They found gamma = 0.47 with uncertainty ranges given in the abstract, which is consistent with the GR prediction of about 0.55. They also found Sigma_Lambda, Sigma_1, and Sigma_2 values close to zero, each reported as fully consistent with the GR case of Sigma = 0, regardless of the Sigma(a) parameterization. The abstract says the constraining power is already competitive and that a factor-of-two improvement is expected from upcoming full-sky galaxy surveys.
What to keep in mind
The analysis was restricted to one-parameter extensions of ΛCDM, so the summary does not cover broader modified gravity models. The abstract does not describe additional limitations beyond this scope restriction.
Key points
- The measured cosmological gravitational potential decay rate is consistent with general relativity.
- The study tested four one-parameter modified gravity parameterizations.
- Gamma was reported as 0.47 with uncertainties and was consistent with the GR prediction of about 0.55.
- Three Sigma-based parameterizations were all consistent with the GR case of Sigma = 0.
- The authors say the method is already competitive, with about a factor-of-two improvement expected from future full-sky galaxy surveys.
Disclosure
- Research title:
- Cosmological potential decay rate is consistent with general relativity
- Authors:
- Xinyi Zhao, Pengjie Zhang, Fuyu Dong
- Institutions:
- Fujian Institute of Research on the Structure of Matter, Institute of Particle Physics, Shanghai Jiao Tong University, Yunnan University
- Publication date:
- 2026-07-03
- OpenAlex record:
- View
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