PD: Improved qubit coherence by materials modeling and ...

Postdoc position in improved coherence by materials modeling and process development   Reference number REF 2024-0439     The Quantum Technology (QT) laboratory at the department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology is on a quest to deliver the milestones set by the Wallenberg Centre for Quantum Technology (WACQT). This 12-year-long research aims to promote Sweden to become a leading power in the field of quantum technology. WACQT is committed to promote career development, diversity, and gender equality through networking and supporting activities.Information about the projectOne of the main projects in WACQT is designing and building a quantum computer with the ability to solve problems beyond the capabilities of even the best conventional supercomputers. Join us if you have expertise in device fabrication and characterization techniques and want to work in a world-class cleanroom, if you are motivated to collaborate with colleagues to build quantum computers and have a career in quantum technology, in academia or at an institute or a company. For more information, visit Wallenberg Centre for Quantum Technology (WACQT) in Sweden and OpenSuperQPlus within the EU Flagship on Quantum Technology.Major responsibilitiesThe reduction of quantum gate errors represents the most important problem in the development of quantum computers in any device technology. By this metric, superconducting qubits constitute a leading platform, with the best demonstrated two-qubit gate errors currently at the 0.1-0.2% level (Sung 2021, Ding 2023). Meaningful quantum computing requires that these errors be reduced to 0.01% in a scalable and reliable way across the multi-qubit chip.These quantum gate errors are fundamentally limited by decoherence. Dielectric loss is the currently dominant decoherence mechanism in superconducting qubits (Burnett 2019). Other important contributions to decoherence originate from phonons and quasiparticles.Here we propose a study of decoherence at the level of the physics of the constituent materials. We foresee that this effort will drastically improve our understanding of the microscopic mechanisms of decoherence and its effect on our devices, which will directly help improve the design and process development of our devices already during the project.Recent works at Chalmers have yielded qubits with a relaxation time of over 250 µs using aluminum (Biznarova 2024). We will build on this work and our other studies on the experimental characterization and numerical modeling of superconducting resonators (Chayanun 2024, Niepce 2020). This project will complement the ongoing process and device development at Chalmers.Y. Sung et al. (2021) Realization of high-fidelity CZ and ZZ-free iSWAP gates with a tunable coupler, Phys. Rev. X 11, 021058L. Ding et al. (2023) High-Fidelity, Frequency-Flexible Two-Qubit Fluxonium Gates with a Transmon Coupler, Phys. Rev. X 13, 031035J. J. Burnett et al. (2019) Decoherence benchmarking of superconducting qubits, npj Quantum Inf 5, 54J. Biznarova et al. (2023) Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits, arXiv:2310.06797L. Chayanun et al. (2024) Characterization of process-related interfacial dielectric loss in aluminum-on-silicon by resonator microwave measurements, materials analysis, and imaging, APL Quantum 1, 026115D. Niepce et al. (2020) Geometric scaling of two-level-system loss in superconducting resonators, Supercond. Sci. Technol. 33 025013 Qualifications o You have a PhD in Physics, Applied Physics, Materials Science, Nanotechnology, or equivalent.o You have expertise in device fabrication and characterization techniques. o You have experience in the design and modeling of microwave circuits. o Your verbal and written communication skills in English are very good.o You are motivated for a career in quantum technology, be it in academia or at an institute or company.o You have a collaborative attitude and an interest in working both independently and collaboratively in a team environment, sharing best practices and assuming responsibility. You are self-motivated, pay attention to detail, and possess a problem-solving analytical ability. You are willing to help supervise PhD students.To qualify for the position of postdoc, you must hold a doctoral degree awarded no more than three years prior to the application deadline (according to the current agreement with the Swedish Agency for Government Employers). Exceptions from the 3-year limit can be made for longer periods resulting from parental leave, sick leave or military service*. The position requires sound verbal and written communication skills in English. Swedish is not a requirement but Chalmers offers Swedish courses. You are expected to be somewhat accustomed to teaching, and to demonstrate good potential within research and education. * The date shown in your doctoral degree certificate is the date we use, as this is the date you have met all requirements for the doctoral degree.Contract termsThis postdoc position is a full-time temporary employment for two years.We offer Chalmers offers a cultivating and inspiring working environment in the coastal city of Gothenburg. Read more about working at Chalmers and our benefits for employees.Chalmers aims to actively improve our gender balance. We work broadly with equality projects, for example the GENIE Initiative on gender equality for excellence. Equality and diversity are substantial foundations in all activities at Chalmers.

2024-08-28

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