Ultrafast Polarization of an Electron Beam in an Intense Bi-chromatic Laser Field

Recent high-intensity laser-plasma experiments provided evidence for quantum radiation reaction effects due to hard photon emission. In this talk I will discuss the radiative spin-polarization of the electrons as a manifestation of quantum radiation reaction affecting the spin-dynamics. It is demonstrated that radiative polarization of high-energy electron beams can be achieved in collisions with bi-chromatic laser pulses, by employing both a Boltzmann kinetic approach and a Monte-Carlo algorithm within the quasi-classical approximation of intense field QED. I will present simulations for a near-term experimentally feasible scenario of a 8 GeV electron beam scattering from a 1 PW laser pulse. Aspects of spin dependent radiation reaction are also discussed, with spin polarization leading to a measurable splitting of the energies of spin-up and spin-down electrons.