The reduction of quantum gate errors is the most important problem in the development of quantum computers in any technological platform. By this metric, superconducting qubits are a leading platform, with the best demonstrated two-qubit gate errors currently at the 0.1% level. This is at the threshold of the required precision for meaningful quantum computing - when achieved in a reliable way across a multi-qubit chip. These quantum gate errors are most fundamentally limited by decoherence, with important contributions from dielectric loss, phonons, and quasiparticles. Here we propose a joint experimental and theoretical 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. We will build on recent work by the Aalto PI on numerical modeling of device geometry and dielectric loss (Lahtinen 2020), and by the Chalmers PIs on the experimental characterization and numerical modeling of the same (Burnett 2019, Niepce 2020, Biznárová 2023). This collaboration will complement the ongoing process and device development at Chalmers and the modeling work at Aalto, with a unique joint problem focus.
J. Lahtinen & M. Möttönen (2020) Effects of device geometry and material properties on dielectric losses in superconducting coplanar-waveguide resonators, J. Phys.: Condens. Matter 32 405702
J. J. Burnett et int. J. Bylander (2019) Decoherence benchmarking of superconducting qubits, npj Quantum Inf 5, 54
D. Niepce et int. J. Bylander (2020) Geometric scaling of two-level-system loss in superconducting resonators, Supercond. Sci. Technol. 33 025013
J. Biznárová et int. J. Bylander, A. Fadavi (2023) Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits, arXiv:2310.06797
Qualifications
To qualify for the position of postdoc, you must hold a doctoral degree in Physics, Applied Physics, Material Science, Nanotechnology, or equivalent, awarded no more than three years prior to the application deadline (according to the current agreement with the Swedish Agency for Government Employers).
o You have expertise in device fabrication, characterization, and/or modeling techniques o You are interested in building quantum computers and are aiming for a career in quantum technology o Your verbal and written communication skills in English are very good 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
About Chalmers
The Wallenberg Centre for Quantum Technology (WACQT) is a 12-year program aiming to promote Sweden to a leading position in quantum technology. A main aim of WACQT is to design and build a superconducting quantum computer with the ability to solve problems beyond the reach of even the best conventional supercomputers.
We are now looking to fill a postdoc position in collaboration between Chalmers University of Technology in Gothenburg and Aalto University in Finland. The project is also in close connection to the OpenSuperQPlus project within the EU Flagship on Quantum Technology.
Join us if you have expertise in device fabrication and characterization techniques and want to work in a world-class cleanroom. You will be a good fit if you are motivated to collaborate with colleagues to build quantum computers and to launch a career in quantum technology. WACQT is committed to promoting career development, diversity, and gender equality through networking and supporting activities.
How to apply
Please apply on Chalmers' website
Chalmers University of Technology
Chalmers University of Technology
41296 Göteborg, Schweden
Reducing qubit decoherence by modeling and fabrication
The reduction of quantum gate errors is the most important problem in the development of quantum computers in any technological platform. By this metric, superconducting qubits are a leading platform, with the best demonstrated two-qubit gate errors currently at the 0.1% level. This is at the threshold of the required precision for meaningful quantum computing - when achieved in a reliable way across a multi-qubit chip. These quantum gate errors are most fundamentally limited by decoherence, with important contributions from dielectric loss, phonons, and quasiparticles. Here we propose a joint experimental and theoretical 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. We will build on recent work by the Aalto PI on numerical modeling of device geometry and dielectric loss (Lahtinen 2020), and by the Chalmers PIs on the experimental characterization and numerical modeling of the same (Burnett 2019, Niepce 2020, Biznárová 2023). This collaboration will complement the ongoing process and device development at Chalmers and the modeling work at Aalto, with a unique joint problem focus.
J. Lahtinen & M. Möttönen (2020) Effects of device geometry and material properties on dielectric losses in superconducting coplanar-waveguide resonators, J. Phys.: Condens. Matter 32 405702
J. J. Burnett et int. J. Bylander (2019) Decoherence benchmarking of superconducting qubits, npj Quantum Inf 5, 54
D. Niepce et int. J. Bylander (2020) Geometric scaling of two-level-system loss in superconducting resonators, Supercond. Sci. Technol. 33 025013
J. Biznárová et int. J. Bylander, A. Fadavi (2023) Mitigation of interfacial dielectric loss in aluminum-on-silicon superconducting qubits, arXiv:2310.06797
Qualifications
To qualify for the position of postdoc, you must hold a doctoral degree in Physics, Applied Physics, Material Science, Nanotechnology, or equivalent, awarded no more than three years prior to the application deadline (according to the current agreement with the Swedish Agency for Government Employers).
o You have expertise in device fabrication, characterization, and/or modeling techniques o You are interested in building quantum computers and are aiming for a career in quantum technologyo Your verbal and written communication skills in English are very goodo 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
About Chalmers
The Wallenberg Centre for Quantum Technology (WACQT) is a 12-year program aiming to promote Sweden to a leading position in quantum technology. A main aim of WACQT is to design and build a superconducting quantum computer with the ability to solve problems beyond the reach of even the best conventional supercomputers.
We are now looking to fill a postdoc position in collaboration between Chalmers University of Technology in Gothenburg and Aalto University in Finland. The project is also in close connection to the OpenSuperQPlus project within the EU Flagship on Quantum Technology.
The position is hosted at the Quantum Technology Laboratory at the Department of Microtechnology and Nanoscience (MC2) at Chalmers and is supervised by Assoc. Prof. Jonas Bylander and Dr. Anita Fadavi(Chalmers) and by Prof. Mikko Möttönen (Aalto).
Join us if you have expertise in device fabrication and characterization techniques and want to work in a world-class cleanroom. You will be a good fit if you are motivated to collaborate with colleagues to build quantum computers and to launch a career in quantum technology. WACQT is committed to promoting career development, diversity, and gender equality through networking and supporting activities.
