Copernicus Webinar and Colloquium Series



Dear colleagues,
We would like to invite you to take part in the upcoming 144th  Copernicus Webinar.
Time:              26th September, Tuesday, at 3pm CEST (9 pm Beijing, 10pm JST, 9 am EDT)
Speaker:         James Cline (McGill University)

Phantom fluid cosmology: constraints and direct detection


Phantom fields have been widely invoked as a source of dark energy in cosmology, but rarely taken seriously as quantum theories. The vacuum is automatically unstable to production of negative-energy ghost particles plus normal particles, requiring such theories to be effective only, below some UV cutoff. I will present recent cosmological constraints arising from the vacuum instability, both at the level of the homogeneous background, and the density perturbations.  We find that the fluid of particles produced from vacuum decay can ameliorate but not solve the notorious Hubble tension problem, and cannot fully replace the cosmological constant as a source of dark energy.  The vacuum decay can be a source of boosted dark radiation, which might be detectable if it interacts with ordinary matter. I will show that this could fit recent excess events reported by the DAMIC experiment at SNOLAB.

Zoom link:
Meeting ID: 421 480 1692
Passcode: cosmology