Superconducting Quantum Interferences Devices (SQUIDs)
Investigation of superconducting Coplanar Waveguide resonators coupled with SQUIDs.
Outline of SQUIDs in the Quantum Laboratory Course
This experiment delves into the investigation of superconducting Coplanar Waveguide (CPW) resonators coupled with Superconducting Quantum Interference Devices (SQUIDs). The CPW structure, featuring a central signal line separated from ground polygons by gaps, allows for varying wave impedances by adjusting the line width and gap dimensions. Resonances emerge due to boundary conditions for standing waves within the CPW, leading to various resonator types such as half and quarter wavelength configurations. These resonators have wide-ranging applications in quantum circuitry, serving as readout circuits for quantum bits and facilitating circuit quantum electrodynamics experiments. Characterization involves measuring the transmission coefficient, which depends on parameters like loaded and coupling quality factors. The experimental setup utilizes Niobium-based CPW resonators coupled with RF-SQUIDs, where the SQUID acts as a flux-dependent inductance, enabling tuning of the resonance frequency by varying the applied magnetic flux for applications like quantum bit readout and radiation detection.
Further content and detailed descriptions are available to enrolled students via the course's page at the Moodle website of the Friedrich Schiller University Jena.