Tractor beams, pressor beams, and stressor beams in general relativity

Understand

The metrics of general relativity generally fall into two categories: Those which are solutions of the Einstein equations for a given source energy-momentum tensor, and the "reverse engineered" metrics -- metrics bespoke for a certain purpose.

• Their energy-momentum tensors are then calculated by inserting these into the Einstein equations.
• This latter approach has found frequent use when confronted with creative input from fiction, wormholes and warp drives being the most famous examples.
• In this paper, we shall again take inspiration from fiction, and see what general relativity can tell us about the possibility of a gravitationally induced tractor beam.