Alexei STAROBINSKY (Landau Institute for Theoretical Physics, Moscow)

Dark Energy

2 lectures: 5, 6 December 2006

1. Definition and observational appearance of dark energy (DE). Its main possible forms: a cosmological constant, physical and geometrical DE. "Fine tuning" and "coincidence" problems - how many and if any? Anthropic explanation - does it work and does it needed?

2. Reconstruction of DE properties from observations: a) from background evolution of a FRW cosmological model; b) from the rate of growth of small perturbations in the non-relativistic matter component (cold dark matter + baryons).

3. Microscopic models of a cosmological constant (the Casimir effect or vacuum polarization due to additional spatial dimensions, string theory models) and variable DE: a) of physical DE - quintessence, Chaplygin gas; b) of geometrical DE - scalar-tensor models, f(R) models, the Dvali-Gabadadze-Porrati model.

1. V. Sahni and A.A. Starobinsky.
Reconstructing dark energy.
IJMPD, 2006, to be published; astro-ph/0610026.

2. R. Gannouji, D. Polarski, A. Ranquet and A.A. Starobinsky.
Scalar-tensor models of normal and phantom dark energy.
JCAP 0609 (2006) 016; astro-ph/0606287.

Lecture notes