Electron matter wave interferences at high vacuum pressures

TL;DR

This study demonstrates that electron coherence remains intact across a wide range of vacuum pressures, suggesting that quantum devices using free electrons can operate under less stringent vacuum conditions than previously thought.

Contribution

The paper provides experimental evidence that electron coherence is maintained at higher background gas pressures, reducing vacuum requirements for quantum electron devices.

Findings

Electron coherence does not decrease between 10^{-9} and 10^{-4} mbar.

Significant signal loss (94%) due to scattering with background molecules.

No observed decoherence despite increased background gas pressure.

Abstract

The ability to trap and guide coherent electrons is gaining importance in fundamental as well as in applied physics. In this regard novel quantum devices are currently developed that may operate under low vacuum conditions. Here we study the loss of electron coherence with increasing background gas pressure. Thereby, optionally helium, hydrogen or nitrogen is introduced in a biprism interferometer where the interference contrast is a measure for the coherence of the electrons. The results indicate a constant contrast that is not decreasing in the examined pressure range between $10^{-9}$ mbar and $10^{-4}$ mbar. Therefore, no decoherence was observed even under poor vacuum conditions. Due to scattering of the electron beam with background H$_2$-molecules a signal loss of 94 % was determined. The results may lower the vacuum requirements for novel quantum devices with free coherent electrons.