1206.6622 (D. V. Karlovets)

Twisted electron in a strong laser wave    [PDF]

D. V. Karlovets

Electrons carrying orbital angular momentum (OAM) have recently been discovered theoretically and obtained experimentally that opens possibilities for using them in high-energy physics. We consider such a twisted electron moving in an external field of a plane electromagnetic wave. Being motivated by the development of high-power lasers, we focus our attention on a classically strong-field regime for which $-e^2 \bar {A^2}/m^2 \gtrsim 1$. It is shown that along with the well-known "plane-wave" Volkov solution, Dirac equation also has the "non-plane-wave" solutions with OAM and a spin-orbit coupling, which generalize the free-electron Bessel states. Motion of the electron with OAM in a circularly polarized wave reveals a twofold quiver character: the wave-packet center moves along a classical helical trajectory accompanied with the pure quantum vibrations around it due to OAM. Using the twisted states, we calculate the electron's total angular momentum and predict its shift in the strong-field regime that is analogous to the well-known shifts of the electron's momentum and mass (and to a less known shift of its spin) in the strong laser fields. Since the electron's effective angular momentum is conserved in a plane wave, as well as in a constant crossed field, we discuss some possibilities for accelerating non-relativistic twisted electrons.

View original: http://arxiv.org/abs/1206.6622