Stasis, Stasis, Triple Stasis

Understand

Many theories of BSM physics predict the existence of large or infinite towers of decaying states.

• In a previous paper (arXiv:2111.04753) we pointed out that this can give rise to a surprising cosmological phenomenon that we dubbed "stasis" during which the relative abundances of matter and radiation remain constant across extended cosmological eras even though the universe is expanding.
• Indeed, such stasis epochs are universal attractors, with the universe necessarily entering (and later exiting) such epochs for a wide variety of initial conditions.
• Matter/radiation stasis is therefore an important and potentially unavoidable feature of many BSM cosmologies.