Two Flavors of Early Dark Energy Ease Cosmic Tension ⚡ экспресс
Constraints imposed by Planck NPIPE CMB data on early dark energy models with axion-like fields are significantly relaxed when moving to multi-field scenarios. In the two-field model, the residual tension with the local H₀ value from the Local Distance Network is 1.5σ; further increasing the number of fields does not improve the agreement. The best-fit H₀ value is about 1.4σ higher than in the single-field case. The second field improves the fit to the data at high multipoles (ℓ), where the single-field model was most problematic, and points to modifications of the pre-recombination history over a wider range of redshifts. Thus, multi-field early dark energy models can alleviate observational contradictions by complicating the dynamics before the recombination epoch.
Cosmologists faced a recipe problem: the universe's expansion rate measured nearby didn't match the rate deduced from the Big Bang's afterglow—the cosmic microwave background. Adding a single type of early dark energy was like tossing in one extra spice, but the flavor still clashed, especially when looking at small-scale details in the afterglow. Now, they've tried a two-spice approach—two types of early dark energy, each appearing at a slightly different moment just after the Big Bang. This blend smooths out the mismatches in the afterglow, bringing the predicted rate of cosmic expansion closer to what local observations, such as those by Adam Riess, measure. The predicted rate jumps from 67 to about 70 kilometers per second per megaparsec, almost reconciling with the local 73.
🎯 The rate is measured in kilometers per second per megaparsec—a megaparsec is 3.26 million light-years. Local methods clock it at 73, the Big Bang afterglow at 67. The two-early-dark-energy model lifts the afterglow's number to about 70, nearly resolving the discrepancy. And here's the twist: those early dark energies flickered for less than a trillionth of a second, yet their signature still ripples through the cosmos today.