• Nuclear, Particle, Astroparticle and Cosmology (NUPAC) Seminars

March 11, 2025 2:00 PM
PAIS 3205

Host:

David Camarena Torres

Presenter:

Kylar Greene (UNM)

Zoom link

A B-mode polarization signal in the cosmic microwave background (CMB) is widely regarded as smoking gun evidence for gravitational waves produced during inflation. In this talk I demonstrate that tensor perturbations from a cosmological phase transition can produce a B-mode signal whose strength rivals that of testable inflationary predictions across a range of observable scales, challenging this conventional wisdom. For appropriately chosen phase transition parameters, the maximal B-mode amplitude can compete with inflationary predictions that can be tested with current and future experiments. These scenarios can be differentiated by performing measurements on multiple angular scales, since the phase transition signal predicts peak power on smaller scales.