Noise scaling in SQUID arrays

TL;DR

This paper numerically studies noise scaling in high-Tc SQUID arrays, revealing deviations from expected models in 1D arrays and more accurate scaling in 2D arrays, impacting low-noise magnetometer design.

Contribution

It provides new insights into noise scaling behaviors in 1D and 2D SQUID arrays, challenging existing scaling rules and guiding low-noise device design.

Findings

Voltage noise spectral density in 1D arrays violates ~1/Np scaling.

2D arrays follow ~Ns/Np scaling more closely.

Flux and magnetic field noise deviate from ~(NsNp)^(-1/2) scaling.

Abstract

We numerically investigate the noise scaling in high-Tc commensurate 1D and 2D SQUID arrays. We show that the voltage noise spectral density in 1D arrays violates the scaling rule of ~1/Np for the number Np of Josephson junctions in parallel. In contrast, in 2D arrays with Ns 1D arrays in series, the voltage noise spectral density follows more closely the expected scaling behaviour of ~Ns/Np. Additionally, we reveal how the flux and magnetic field rms noise spectral densities deviate from their expected ~(NsNp)^(-1/2) scaling and discuss their implications for designing low noise magnetometers.