Predictions→ ALP Birefringence
ALP Birefringence
A model-dependent ALP field-evolution calculation motivates a β value near 0.27°. Existing birefringence measurements have systematic and model-dependence questions and do not validate a bounce scenario.
Supporting theoretical context
Conditional β model value
ECH (ALP field evolution)
LiteBIRD (~2032)
Current Constraint
Published CMB rotation estimates provide external context only. They are not an in-house validation of the β calculation or evidence that a bounce occurred.
Key Results
- A model-dependent ALP calculation motivates β near 0.27°
- External birefringence estimates do not identify a bounce mechanism
- Foreground and estimator systematics remain material
- An injection-recovery exercise checks a pipeline response, not the physical model