Jul 15 – 19, 2024
Perimeter Institute for Theoretical Physics
America/Toronto timezone

Assessing observational constraints on dark energy

Jul 16, 2024, 2:30 PM
15m
Federation Hall (University of Waterloo)

Federation Hall

University of Waterloo

Contributed Talk Contributed Talks

Speaker

David Shlivko (Princeton University)

Description

Observational constraints on time-varying dark energy are commonly presented in terms of the two CPL parameters $w_0$ and $w_a$. Recent observations favor a sector of this parameter space in which $w_0 > -1$ and $w_0 + w_a < -1$, suggesting that the equation of state underwent a transition from violating the null energy condition (NEC) at early times to obeying it at late times. In this talk, I will demonstrate that this initial impression is misleading, by showing that simple quintessence models satisfying the NEC at all times predict an observational preference for the same sector. The upshot is that the CPL parameterization is simultaneously useful for detecting deviations from cosmological-constant dynamics ($w = -1$) but unreliable for predicting the true behavior of $w(z)$.

Contact Email [email protected]

Primary author

David Shlivko (Princeton University)

Presentation materials

There are no materials yet.

External references