Abraham's force on a highly dispersive medium

We consider the radiation force on highly dispersive media. In doing so we reconsider an experiment proposed to measure the "Abraham force" term in the stress-energy tensor at optical frequencies by measuring the displacement of a transparent dielectric caused by a light pulse passing through it. We demonstrate that, using a cold atomic vapor with a large normal dispersion as the sample medium, such an experiment should now be feasible. We also show that this radiation force can be measured for a light pulse in a highly anomalously dispersive medium, where the group velocity exceeds c. This leads to the non-intuitive result that the sample recoil changes direction.