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Astronomy Tea Talks at Caltech

Mondays, Robinson 106
Tea:  4.00pm
Talk: 4.15pm

Organised by:

2007 - 2008 season:
2 June 2008 Richard Bond (U. of Toronto & CITA)

"Constraining trajectories of dark energy inflatons"


I will describe what theory allows and what it prefers for the ensemble of acceleration trajectories now, in the late universe, and contrast it with
then, in the early universe. Standard low order and partially blind parameterizations of the dark energy equation of state 1+w(a) give viable inflaton
trajectories, but quite baroque potentials. We develop a slow-to-moderate roll 3-parameter approximation which accurately paves the space of w(a)
trajectories for a wide variety of quintessence and phantom energy potentials. The main parameter, eps_s ~ (inflaton potential slope)^2. It
encapsulates the same content as the oft-used w_0 but is far more physical. eps_s is reasonably well-constrained by the May08 SN, weak lensing, BAO,
CMB, and Lya data, and consistent with a flat potential (aka cosmological 'constant'). Future weak lensing (DUNE-ish), SN (JDEM-ish) and CMB
(Planck1-ish) will improve errors on eps_s by more than a factor of 3. Unless the potentials is baroque, e.g giving many ups and downs in w(a), future
reconstruction of the late-inflaton potential is (tragically) unlikely, with even the next order change in eps_s ill-determined.
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Last modified on 20th Jul 2011 by Johan Richard.  

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