Next-generation telescopes can now look for a specific glitch in the sky that proves space itself once changed states.
Quantum gravity is famously hard to test, but this new model provides a direct observational signature. It predicts that a phase transition during the birth of the universe left a 0.8% modulation in the cosmic background light. This tiny imprint should be visible to upcoming telescopes like the CMB-S4. Finding this pattern would be the first direct evidence of how spacetime behaves at the smallest possible scales. It turns a purely theoretical problem into a concrete target for astronomers to find.
Imprints of Spacetime Phase Transition in the Cosmic Microwave Background: Testable Predictions for CMB-S4
SSRN · 6618818
Quantum gravity phenomenology has long been limited by the inaccessibility of Planck-scale physics, lacking falsifiable low-energy observational windows. In this work, we propose a momentum-dependent spacetime phase transition mechanism during cosmic inflation: as the physical momentum of a comoving perturbation mode redshifts with the expansion of the universe, the spacetime governing the mode undergoes a transition from a noncommutative phase to a commutative phase when the mode crosses the no