Physicists Discover Particle with Mass Only When Moving in One Direction

Scientists have discovered a peculiar quasiparticle, the semi-Dirac fermion, which only exhibits effective mass when moving in one direction. Predicted in 2008, this phenomenon has now been confirmed in a ZrSiS semi-metal crystal at extremely low temperatures (-269°C). Its energy properties differ drastically in perpendicular directions, akin to a train experiencing resistance when switching tracks, thus gaining mass. This discovery could have profound implications for quantum physics and electronic sensors, but further research is needed to explore its applications.