PhD position in Hybrid Cavity Quantum Electrodynamics with Ge semiconductor QDs and high impedance superconducting resonators

We are excited to announce a unique opportunity for a highly motivated PhD candidate to join our ongoing collaborative research effort in the field of experimental quantum information science, focusing on spin qubits and hybrid superconducting-semiconductor quantum devices. This position is offered in a shared initiative between the laboratories of Prof. Wallraff and Prof. Scarlino, respectively in ETH Zurich and EPFL. The research activity closely aligns with and is supported by the NCCR SPIN (a Swiss National Center of Competence in Research) in Switzerland, focusing on hole spin qubits.

This position is available immediately, with a flexible start date. We will start reviewing applications on June 15, 2024, and continue until the position is filled.

The successful candidate will join our experimental teams in advancing our capabilities in quantum information processing with quantum dots and hole spin qubits implemented in planar Germanium. Our project is a collaborative effort between the Quantum Device Lab at ETH Zurich and the Hybrid Quantum Circuit lab at EPFL. This collaboration is part of the NCCR SPIN, which aims to drive cutting-edge research in the field of quantum technology focusing on hole-spin qubits.

As the successful candidate, you will become an essential member of our experimental teams, contributing to the advancement of quantum information processing using hybrid superconducting-semiconductor quantum devices, particularly spin qubits in electrostatically defined quantum dots. Your research will have an emphasis on developing novel readout techniques for spin quantum dot-based qubits, hybrid QD-cavity systems, and flip-chip technology integration.

The project's primary focus is on exploring fast and high-fidelity readout techniques for quantum dot spin qubits, making use of their coupling to high-impedance resonators. Quantum dots and hole spin qubits in planar Germanium offer unique advantages for quantum information processing, including longer coherence times and all electrical-based manipulation. Our groups are also currently developing novel parametric amplifiers which will be an essential component to maximize the readout performance.

Our team has recently achieved significant advancements in coupling the charge and spin degrees of freedom defined in semiconducting quantum dots (QDs) with superconducting resonators and qubits. These developments have enhanced our capabilities of strongly coupling to and reading out spin qubits. Building on this progress, we now aim to leverage our quantum technology expertise and the optimization processes already established at the Quantum Device Lab for superconducting qubits to enhance the readout of spin qubits. To achieve this, we plan to utilize well-designed Purcell filters, strongly coupled readout resonators, and either Josephson-junction-based or kinetic-inductance-based parametric amplifiers. Our goal is to elevate the readout fidelity of spin qubits to above 99% while reducing the integration time to less than 100 ns.

The design, workflow, fabrication processes, and measurement techniques we employ are closely aligned with those used for traditional superconducting qubits. As part of this effort, we are collaborating extensively with the core teams within the NCCR SPIN to drive forward the development of spin qubit-based quantum technology.

Division and Department Information:

This collaborative research project is jointly conducted at ETH Zurich and EPFL, two world-renowned institutions in quantum research which provide a rich scientific environment and unparalleled resources in the field of quantum information science.

During this project, you will be at the forefront of experimental research, both independently and as a member of our research team. Your responsibilities may encompass:

• Conceptualizing and designing innovative quantum devices and systems
• Conducting advanced microwave measurements with a focus on quantum-limited noise performance
• Developing customized solutions for the control and readout of spin qubits
• Exploring scalability aspects of hybrid quantum systems
• Engaging in material studies and advancing nanofabrication processes to enhance qubit performance
• Fabricating superconducting and semiconducting devices, with the potential to collaborate with other teams within the research groups
• Becoming a member of our fabrication team to contribute to the development of flip-chip technology integration

Your research will benefit from the comprehensive infrastructure, expertise, and collaborative network available within our research groups and across the NCCR SPIN. Regular interactions with theory collaborators, both within Switzerland and internationally, will be integral to your research activities.

As a Ph.D. student, you will also play a role in providing informal supervision to graduate/master students.

We are seeking candidates who hold (or are nearing the completion) a master’s degree in physics, Engineering Physics, or Applied Physics. You should have a strong interest and expertise in at least two of the following areas: experimental quantum processors, quantum information science, quantum optics, superconducting devices, microwave engineering, nanofabrication, and flip-chip technology integration.

A future career in research and development or education, whether in academia or industry, should align with your career aspirations. You should possess a genuine curiosity for scientific exploration and a drive to create impact in quantum research. Proficiency in English, both in reading and writing scientific materials, is a prerequisite. Exceptional candidates with a demonstrated track record in any field of physics, engineering physics, or nanotechnology will be considered. Previous experience in nanofabrication, particularly of superconducting circuits or mesoscopic electronic devices, will be regarded as an asset. Familiarity with experimental condensed-matter physics, quantum optics, and quantum technology is appreciated.

Contract Terms:

This PhD position offers full-time temporary employment.

Joining our collaborative research project provides access to a stimulating and inspiring work environment at ETH Zurich and EPFL Switzerland.