Magnetic flux detection with an Andreev Quantum Dot

TL;DR

This paper investigates the use of an Andreev quantum dot embedded in a superconducting loop as a highly sensitive magnetic flux detector, analyzing its performance considering Coulomb interactions and large superconducting gaps.

Contribution

It provides a theoretical analysis of the flux sensitivity of an Andreev quantum dot device, including Coulomb effects, highlighting its potential for detecting weak magnetic fields.

Findings

Sensitivity depends on device parameters and Coulomb interaction strength.

Large superconducting gap enhances flux detection capabilities.

Potential application in weak magnetic field sensing.

Abstract

The charge of the subgap states in an Andreev quantum dot (AQD; this is a quantum dot inserted into a superconducting loop) is very sensitive to the magnetic flux threading the loop. We study the sensitivity of this device as a function of its parameters for the limit of a large superconducting gap. In our analysis, we account for the effects of a weak Coulomb interaction within the dot. We discuss the suitability of this setup as a device detecting weak magnetic fields.