Towards a test of quantum dissipation theory.

We report on the progress of an experiment to observe dissipation of kinetic energy of electron beam and quantum decoherence of the electron diffraction pattern as predicted by the Caldiera-Legget theory as a consequence of propagation over a conducting surface [1]. In a previous experiment, we found that an electron passing close to a conducting surface did not exhibit the level of decoherence one would expect [2]. One explanation is that the energy dissipation is smaller than predicted. The energy loss for charged particle with constant velocity travelling over a conductor have been modelled within classical electrodynamics by Boyer [3], and the predictions suggest an energy loss of ≈ 17 eV for a beam flying at a 20 micron height over a 1 cm long GaAs surface. Currently, we are measuring this with a retarding field analyzer (RFA). A relative resolution of 50 meV at an energy of 1600 keV is reached in a measuring time of 1 second. Using laser light to excite the conduction band of the GaAs surface, we can vary the resistivity of the GaAs surface. Additionally, the electron matter wave spatial coherence has been improved from 500 nm to exceed 1 μm, to improve the sensitivity to decoherence.

[1] A. Caldeira and A. Leggett, Annals of Physics 149, 374 (1983).

[2] P. J. Beierle, L. Zhang, and H. Batelaan, New J. Phys. 20, 113030 (2018); Z. Chen and H. Batelaan, Europhys. Lett. 129, 40004 (2020).

[3] T.H Boyer, Phys. Rev. A 9, 68 (1974).