Electric field noise in a high-temperature superconducting surface ion trap

TL;DR

This study explores electric field noise in a high-temperature superconductor YBCO surface ion trap, revealing a $1/f$ spectral dependence and a temperature-dependent noise plateau linked to superconductivity, informing future quantum trap designs.

Contribution

It demonstrates negligible voltage noise from YBCO electrodes and characterizes the frequency and temperature dependence of electric field noise in a high-temperature superconductor trap.

Findings

Voltage noise from superconducting leads is negligible.

Electric field noise exhibits a $1/f$ spectral dependence.

A noise plateau appears around the superconducting transition temperature.

Abstract

Scaling up trapped-ion quantum computers requires new trap materials to be explored. Here, we present experiments with a surface ion trap made from the high-temperature superconductor YBCO, a promising material for future trap designs. We show that voltage noise from superconducting electrode leads is negligible within the sensitivity $S_V=9\times 10^{-20}\,\mathrm{V}^2\mathrm{Hz}^{-1}$ of our setup, and for lead dimensions typical for advanced trap designs. Furthermore, we investigate the frequency and temperature dependence of electric field noise above a YBCO surface. We find a $1/f$ spectral dependence of the noise and a non-trivial temperature dependence, with a plateau in the noise stretching over roughly $60\,\mathrm{K}$. The onset of the plateau coincides with the superconducting transition, indicating a connection between the dominant noise and the YBCO trap material. We exclude the YBCO bulk as origin of the noise and suggest further experiments to decide between the two remaining options explaining the observed temperature dependence: noise screening within the superconducting phase, or surface noise activated by the YBCO bulk through some unknown mechanism.