Joel K. Erickson

Cosmic Perturbations Through the Cyclic Ages (2006)

Erickson, Joel K., Gratton, Steven, Steinhardt, Paul J., Turok, Neil

We analyze the evolution of cosmological perturbations in the cyclic model, paying particular attention to their behavior and interplay over multiple cycles. Our key results are: (1) galaxies and...

Kasner and Mixmaster behavior in universes with equation of state w \ge 1 (2003)

Erickson, Joel K., Wesley, Daniel H., Steinhardt, Paul J., Turok, Neil

We consider cosmological models with a scalar field with equation of state $w\ge 1$ that contract towards a big crunch singularity, as in recent cyclic and ekpyrotic scenarios. We show that chaotic...

Measuring the Speed of Sound of Quintessence (2001)

Erickson, Joel K., Caldwell, R. R., Steinhardt, Paul J., Armendariz-Picon, C., Mukhanov, V.

Quintessence, a time-varying energy component that may account for the accelerated expansion of the universe, can be characterized by its equation of state and sound speed. In this paper, we show...