On the physical (im)possibility of lightsabers

摘要

In this paper, we use a science-fiction theme (i.e. the iconic lightsaber from the Star Wars universe) as a pedagogical tool to introduce aspects of nonlinear electrodynamics due to the quantum vacuum to an audience with an undergraduate physics background. In particular, we focus on one major problem with lightsabers that is commonly invoked as an argument to dismiss them as unrealistic: light blades are not solid and thus cannot be used in a duel as normal swords would. Using techniques coming from ultra intense laser science, we show that for high enough laser intensities, two lightsaber blades can 'feel' solid to each other. We argue that this aspect of lightsabers is not impossible due to limitations of the laws of physics, but is very implausible due to the high intensities and energy needed for their operation.