Pointlike probes of superstring-theoretic superfluids

Understand

In analogy with an experimental setup used in liquid helium, we use a pointlike probe to study superfluids which have a gravity dual.

• In the gravity description, the probe is represented by a hanging string.
• We demonstrate that there is a critical velocity below which the probe particle feels neither drag nor stochastic forces.
• Above this critical velocity, there is power-law scaling for the drag force, and the stochastic forces are characterized by a finite, velocity-dependent temperature.