Utilizing circuit QED techniques for long-range two-qubit coupling and the study of quantum matter
Superconducting resonators enable strong coupling to, and between, nanoscale quantum systems, and as a result have emerged as essential tools for both quantum information and quantum sensing. In this talk, I will discuss new applications of superconducting resonators in both of these fields.
First, I will discuss using a high-impedance superconducting resonator to mediate long-ranged interactions between two semiconductor quantum dot singlet-triplet spin qubits.
Using this architecture, we are able to realize a longitudinal coupling between the resonator and qubit. This novel type of interaction has a number of advantages over the more commonly considered transverse coupling: it does not require careful tuning of the qubit frequency to match that of the resonator, which facilitates scaling to a large number of qubits, and also avoids the loss of coherence which is inevitable in resonant coupling. I will also discuss technical developments which proved crucial to the success of implementing this hybrid spin-qubit-resonator system in GaAs heterostructures.
In addition, I will describe my recent work developing a new technique in quantum sensing, where we employ superconducting resonators as a probe of quantum materials. The confinement of electromagnetic fields in superconducting resonators enables strong coupling to mesoscopic systems such as two-dimensional materials, heterostructures, and nanowires, which are otherwise challenging to experimentally access with conventional techniques. In particular, I will discuss how the symmetry of the superconducting order parameter in an unconventional superconductor can be detected using this technique by its influence on a hybrid resonator circuit.
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