PhD student

Quantum electronics:
Gate-based sensing of spin qubits

Ref. 2020_006

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Project description

Spin qubits realized in gate-defined silicon quantum dots demonstrate excellent coherence and very long decay times. Because of their small size and the availability of rapid two-qubit gates, spin qubits are considered as a platform that can be scaled to many qubits. One of the challenges is to perform a fast and high-fidelity read-out of the spin state of the qubits. Typically, a separate charge sensor is needed that can be quickly read-out using dispersive read-out techniques. In a scalable architecture, it is preferred to avoid the overhead of the charge sensor and use reflectometry of a resonator circuit in the microwave frequency range that is directly connected to the gate electrode of the quantum dot itself [1,2].

In this project, we will investigate gate-based dispersive sensing of spin qubits using microwave resonators integrated on the silicon substrate [3]. Quantum dots and microwave resonators will be designed and fabricated in our BRNC cleanroom. Microwave and DC measurements will be performed in dedicated dilution refrigerators. The goal is to establish single-shot measurements of spin qubits in a scalable architecture using small-footprint microwave resonators.

[1] A. West et al., Nat. Nanotechnol. 14, 437 (2019). DOI

[2] M. Urdampilleta et al., Nat. Nanotechnol. 14, 737 (2019). DOI

[3] G. Zheng et al., Nat. Nanotechnol. 14, 742 (2019). DOI

Requirements

We are looking for a highly motivated physicist with an outstanding proficiency in quantum physics and semiconductor physics. The candidate should be interested in experimental work and be driven by the desire to develop analytical and numerical models to understand the measured data. Good programming skills preferentially in Python or matlab, experience with clean-room sample fabrication, RF measurement techniques and transport measurements in cryostats are desired.

Diversity

IBM is committed to diversity at the workplace. With us you will find an open, multicultural environment. We offer a diverse, independent professional activity, with experienced colleagues in a friendly atmosphere on our campus. You will find a dynamic, multi-cultural environment, and flexible working conditions. Women are expressly invited to apply.

Questions? Contact the PI .