Understanding Chameleon Scalar Fields via Electrostatic Analogy – Kate Jones-Smith

Date: Tue. October 18th, 2011, 11:30 am-12:30 pm
Location: Rockefeller 221

The late-time accelerated expansion of the universe could be caused by a scalar field that is screened on small scales, as in chameleon or symmetron scenarios. We present an analogy between such scalar fields and electrostatics, which allows calculation of the chameleon field profile for general extended bodies. Interestingly, the field demonstrates a `lightning rod’ effect, where it becomes enhanced near the ends of a pointed or elongated object. Drawing from this correspondence, we show that non-spherical test bodies immersed in a background field will experience a net torque caused by the scalar field. This effect, with no counterpart in the gravitational case, can be potentially tested in future experiments.