Berlin 2014 – wissenschaftliches Programm
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MP: Fachverband Theoretische und Mathematische Grundlagen der Physik
MP 5: Klassische Feldtheorie und Statistische Mechanik
MP 5.3: Vortrag
Dienstag, 18. März 2014, 17:55–18:15, SPA SR125
Plane waves as tractor beams — Péter Forgács1,2, •Árpád Lukács1, and Tomasz Romanczukiewicz3 — 1Wigner RCP RMKI, Budapest, Hungary — 2LMPT, Université de Tours, France — 3Jagiellonian University, Krakow, Poland
It is shown that in a large class of systems plane waves act as tractor beams: i.e., an incident plane wave can exert a pulling force on the scatterer. The underlying physical mechanism for the pulling force is due to the sufficiently strong scattering of the incoming wave into another mode carrying more momentum, in which case excess momentum is created behind the scatterer. This tractor beam or negative radiation pressure (NRP) effect is found to be generic in systems with multiple scattering channels. In a birefringent medium electromagnetic plane waves incident on a thin plate exert NRP of the same order of magnitude as optical radiation pressure, while in artificial dielectrics (metamaterials) the magnitude of NRP can be even macroscopic. In two dimensions we study various scattering situations on vortices, and NRP is shown to occur by the scattering of heavy baryons into light leptons off cosmic strings, thereby reducing the friction acting on cosmic strings moving in a surrounding plasma of particles (the dominant energy loss mechanism for cosmic strings in the friction era). It is shown, that the famous enhancement of the small angle cross section for cosmic strings is another manifestation of this phenomenon, and that this enhancement also occurs for neutron scattering off vortices in the XY model.