Momentum-induced Zitterbewegung of massless relativistic quasiparticles emreged in an optical lattice

We have investigated dynamic characteristics of massless Dirac and hybrid quasiparticles in an optical lattice. Zitterbewegung (ZB) of the quasiparticles has been realized and well manipulated. The results reveal that massless Dirac quasiparticles can also generate ZB oscillation, only with an initial velocity being introduced to the quasiparticles as the price to pay. Besides, we noticed an essential distinction between this momentum-induced ZB and an ordinary ZB generated by massive Dirac particles, i.e., instead of all directions, ZB induced by momentum in a 2D system will emerge exclusively in the direction orthogonal to where the momentum is introduced. On the other hand, momentum-induced ZB will be attenuated more rapidly since the initial momentum causes greater expansion rate of wave packets. Therefore, an optimal range of parameters is necessary in detecting such ZB. We have confidence that momentum-induced ZB for massless Dirac quasiparticles will be observed in the near future since the frequency, amplitude and lifespan of ZB can now be controlled in a detectable range in the cold atom system.