Cheating light pulses break Newtonian law

摘要

Isaac Newton just got cheated. Laser pulses have been made to accelerate themselves around loops of optical fibre, seeming to break the physicist's law that every action must have an equal and opposite reaction. The work exploits a trick with light that only makes it appear to have mass, so it is a bit of a dodge. But it may one day lead to faster electronics and more reliable communication. According to Newton's third law of motion, when one billiard ball strikes another, the two balls will shoot away from each other in opposing directions. But if one of the billiard balls had a negative mass, then when the two balls collide they will accelerate in the same direction. This effect could be useful in a diametric drive, a speculative "engine" in which the negative and positive mass interact to accelerate forever. The trouble is that quantum mechanics states that matter cannot have a neeative mass.