Name: Erminia Calabrese
 Institution: University of Rome 'La Sapienza', Physics Department
 Title: 'Probing the dark energy sound speed with lensing'
 Key Words: dark energy sound speed
 Abstract: I present new constraints on early dark energy models using future CMB datasets, like Planck and CmbPol. I will show the effect of this component on other cosmological parameters such as the sound speed and viscosity. I will, in particular, focus on the contribution of CMB lensing to the estimation.