Condensed Matter Seminar Series

 Ripplonic Lamb Shift for Electrons on Helium Surface

Mark I. Dykman

Michigan State University

Thursday December 1,  11:30 am,  Room 298,  Physics Building

Abstract: Electrons on helium surface is an ideal system for studying many-body phenomena, as it is free from disorder. I will discuss some recently found phenomena related to the electron coupling to capillary waves on the helium surface, ripplons, and to the electron-electron interaction. I will show that two-ripplon processes lead to the Lamb-like shift of the energy levels of quantized electron motion normal to the surface. The shift is free from the strong divergence that appears if, following conventional wisdom, one disregards the 3D character of the electron motion. It displays a characteristic temperature dependence, which is in quantitative agreement with the experiment. I will also show that two-ripplon processes play a smaller role in the electron energy relaxation than previously assumed. This leads to a long coherence time of qubits based on quantized lateral states in quantum dots on helium surface placed into a microwave cavity. I will also discuss a long-sought effect, the onset of intrinsic resonant bistability of the response of a quasi-2D electron system to a microwave field, which has been recently seen in the experiment on electrons on helium and which is due to the electron correlations.