Electron Dynamics in Quantum Dots on Helium Surface

TL;DR

This paper investigates electron behavior in quantum dots on helium, highlighting how confinement and external fields influence relaxation and coherence, with implications for quantum computing qubits.

Contribution

It provides a detailed analysis of electron energy spectra, relaxation mechanisms, and ways to suppress decoherence in helium-based quantum dots.

Findings

Strong in-plane confinement slows electron relaxation

Energy relaxation mainly due to helium phonons

Magnetic fields further suppress decay rates

Abstract

We study single-electron quantum dots on helium surface created by electrodes submerged into the helium. The intradot potential is electrostatically controlled. We find the electron energy spectrum and identify relaxation mechanisms. Strong in-plane confinement significantly slows down electron relaxation. Energy relaxation is due primarily to coupling to phonons in helium. Dephasing is determined by thermally excited ripplons and by noise from underlying electrodes. The decay rate can be further suppressed by a magnetic field normal to the helium surface. Slow relaxation in combination with control over the energy spectrum make localized electrons appealing as potential qubits of a quantum computer.