Superconducting microwave magnetometer for absolute flux detection

Abstract

Superconducting quantum interference devices (SQUIDs) are among the most sensitive detectors for out-of-plane magnetic field components. However, due to their periodic response with short modulation period $M=1{\Phi }_0$, determined by the magnetic flux quantum ${\Phi }_0\approx 2.068\times 10^{-15}\mathrm{Wb}$, it is difficult to infer the value of the magnetic flux unambiguously, especially in case the magnetic flux enclosed in the SQUID loop changes by many flux quanta. Here, we demonstrate that by introducing a second degree of freedom in the form of a second SQUID, we substantially enhance the modulation period $M$ of our device without sacrificing sensitivity. As a proof of concept, we implement our idea by embedding two asymmetric direct current SQUIDs into a common tank circuit. By measuring the reflection coefficient of the device, we extract the two lowest energy eigenfrequencies as a function of the external magnetic flux created by a superconducting field coil, from which we experimentally deduce a modulation period $M\ge 15{\Phi }_0$, as well as the magnetic offset-field $B_0=22\mathrm{nT}$ present in our experiment.

arXiv comment8 pages, 5 figures (+ 6 pages, 3 figures appendix)

References in corpus (14)

• Charge insensitive qubit design derived from the Cooper pair box
• A Quantum Engineer's Guide to Superconducting Qubits
• Evidence of topological superconductivity in planar Josephson junctions
• High Kinetic Inductance Superconducting Nanowire Resonators for Circuit QED in a Magnetic Field
• Correlating decoherence in transmon qubits: Low frequency noise by single fluctuators
• Quasiparticle dynamics in granular aluminum close to the superconductor to insulator transition
• Ultrasensitive magnetic field detection using a single artificial atom
• Implementation of a transmon qubit using superconducting granular aluminum
• Characterizing decoherence rates of a superconducting qubit by direct microwave scattering
• Electron spin resonance detected by a superconducting qubit
• Structural instability of driven Josephson circuits prevented by an inductive shunt
• Local Sensing with the Multi-Level AC Stark Effect
• NanoSQUID magnetometry of individual cobalt nanoparticles grown by focused electron beam induced deposition
• A new family of field-stable and highly sensitive SQUID current sensors based on sub-micrometer cross-type Josephson junctions