Gravitationally Induced Photon Creation Modifies T(z) Relation While Preserving Planck Spectrum
Trevisani et al. demonstrate that gravitationally driven adiabatic photon creation preserves the CMB blackbody spectrum while changing the temperature-redshift law, offering a thermal-sector test of LambdaCDM and a potential route to the H0 tension. The finding rests on convergent derivations from thermodynamics and kinetic theory.
Standard cosmology assumes photon number conservation after recombination, fixing both the blackbody spectrum and T proportional to (1+z). The new treatment incorporates gravitational photon creation as an irreversible process, yielding a modified temperature-redshift relation that remains consistent across macroscopic entropy balance and microscopic kinetic equations. This framework also accommodates observed CMB anisotropies without introducing spectral distortions beyond standard limits.
The result directly questions the blackbody assumption underlying LambdaCDM thermal history by allowing net photon injection tied to expansion dynamics. It connects to H0 tension discussions because altered early-universe photon density could shift sound-horizon calibration without spoiling the Planck spectrum. Existing FIRAS bounds on mu and y distortions remain compatible provided creation is sufficiently adiabatic.
Next steps require high-redshift T(z) measurements from CO or fine-structure lines at z greater than 2 to test the predicted deviation. A 3-sigma departure from the canonical law at z=3 would falsify photon-number conservation and force revision of recombination physics.
JWST or ALMA: measured T(z) at z=2.5 deviates >4% from (1+z) within 4 years if creation rate exceeds 10^-3 per Hubble time
Sources (2)
- [1]Primary Source(https://arxiv.org/abs/2606.17072)
- [2]Supporting Source(https://arxiv.org/abs/astro-ph/0603458)