  Particle phase transitions in the early universe including electroweak and
grand unification ones are well-studied subjects. We point out that there are
new possible particle phase transitions around inflation. Those new
inflationary particle phase transitions, if of the first order, may yield
low-frequency gravitational waves (GWs) due to bubble dynamics, leaving
imprints on the cosmic microwave background (CMB). In contrast to the nearly
scale-invariant primordial GWs caused by vacuum fluctuation, these
bubble-generated GWs are classical and have scale dependent B-mode spectra. If
decoupled from inflaton, the electroweak phase transition during inflation may
serve as a mirror image of the one after reheating where the baryon asymmetry
could be generated via electroweak baryogenesis (EWBG). The second new
electroweak phase transition may also be the source for EWBG.
