Sean Carroll is a Senior Research Associate in Physics at the California Institute of Technology. He previously worked at MIT, UC Santa Barbara, and the University of Chicago. He studies topics in theoretical physics, focusing on cosmology, field theory, particle physics, and gravitation. He is currently studying the nature of dark matter and dark energy, connections between cosmology, quantum gravity, and statistical mechanics, and scenarios for the beginning of the universe. He is a contributor to the blog "Cosmic Variance".