title: Relativistic Electron Wave Packets Carrying Angular Momentum.
abstract: There are important differences between the nonrelativistic and relativistic description of electron beams. In the relativistic case the orbital angular momentum quantum number cannot be used to specify the wave functions and the structure of vortex lines in these two descriptions is completely different. We introduce analytic solutions of the Dirac equation in the form of exponential wave packets and we argue that they properly describe relativistic electron beams carrying angular momentum.
authors.affiliation: Center for Theoretical Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Iwo
authors.initials: I
authors.lastname: Bialynicki-Birula
authors.affiliation: Institute of Physics, Polish Academy of Sciences, Aleja Lotników 32/46, 02-668 Warsaw, Poland.
authors.forename: Zofia
authors.initials: Z
authors.lastname: Bialynicka-Birula