Electron charge coherence on a solid neon surface

TL;DR

This paper theoretically investigates the decoherence mechanisms affecting electron charge qubits on solid neon, explaining the long coherence times observed experimentally and identifying key factors limiting qubit performance.

Contribution

It provides a detailed theoretical analysis of phonon-induced decoherence mechanisms for electron charge qubits on solid neon, highlighting potential for experimental improvements.

Findings

Decoherence mainly caused by phonon-induced surface displacement and permittivity modulation.

Coherence times decrease significantly with increasing qubit frequency.

Theoretical coherence times exceed experimental results, indicating room for enhancement.

Abstract

Recent experiments show ~0.1 ms coherence time for a single electron charge qubit on a solid neon surface. This remarkably long coherence time is believed to result from the intrinsic purity of solid neon as a qubit host. In this paper, we present theoretical studies on the decoherence mechanisms of an electron's charge (lateral motional) states on solid neon. At the typical experimental temperature of ~10 mK, the two main decoherence mechanisms are the phonon-induced displacement of neon surface and phonon-induced modulation of neon permittivity (dielectric constant). With a qubit frequency increasing from 1 GHz to 10 GHz, the charge coherence time decreases from about 366 s to 7 ms and from about 27 s to 0.3 ms, respectively, limited by the two mechanisms above. The calculated coherence times are at least one order longer than the observed ones at ~6.4 GHz qubit frequency, suggesting plenty of room for experimental improvement.