Heidelberg 2015 – scientific programme

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SYTL: Symposium Interactions between Twisted Light and Particles

SYTL 2: Symposium on interactions between twisted light and particles II (SYTL)

SYTL 2.5: Talk

Friday, March 27, 2015, 16:10–16:30, C/gHS

Neutron vortex beams and their interaction with laser pulses — •Armen Hayrapetyan and Jörg Götte — Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden

Vortex beams are known to carry quantized orbital angular momentum along their axes of propagation, they possess phase singularities occurring at the center where the beam intensity is zero. While recent advances in technology have lead to creation of both optical and electron vortex beams, called also twisted light and electrons, there have been striking yet largely unexplored studies on other types of material vortex beams. To deepen this analogy between the light and matter waves, we report on the first study of neutron vortex beams (NVBs) and their interaction with plane-wave laser pulses within the framework of relativistic Dirac theory. The interaction with the field is determined via the anomalous magnetic moment of neutron that manifests itself in the exact, Skobelev solutions of the Dirac equation, analogous to the Volkov states of relativistic electrons. To characterize a twisted state of laser-driven neutrons, we construct analytically exact solutions of the Dirac equation that demonstrate the spin-to-orbit conversion for the NVB and the influence of light upon it. Our new solutions generalize, on the one hand, the recently obtained vortex-beam solutions of the field-free Dirac particles, on the other hand, the Dirac-Skobelev solutions for the laser-driven plane-wave neutrons. We pay a particular attention to the evolution of twisted neutrons in the presence of high-power laser fields that have become accessible during the last decade.