Vacuum Propellers

Fast interstellar travel will never be possible with any kind of rocket, regardless of the energy source (be it chemical, nuclear, or antimatter), due to the need to carry the rocket's reaction mass on board. How can a person who coined the maxim “Never invest in something that violates a conservation law” seriously entertain the possibility of “propellantless propulsion”? This brief document speculates on how a “Vacuum Propeller” might be built which violates no law of physics.