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Systems Engineering for Superconducting Quantum Computing,

Dr. Matteo Mariantoni

Institute for Quantum Computing and Department of Physics and Astronomy
University of Waterloo, Canada

18 Jun 2018 11:30
PGI, building 04.8, seminarroom 337/338, 2nd floor


I will provide a brief introduction to the main technological and scientific challenges to be faced in order to build a practical quantum computer, with emphasis on the case of superconducting quantum computing. I will then delve into a detailed explanation of a method to address the wiring of a two-dimensional array of superconducting quantum bit (qubits): The quantum socket [1]. Next, I will show how the quantum socket can be extended to a medium- and large-scale quantum computer and how it can help mitigate coherent leakage errors due to qubits interacting with spurious cavity modes [2]. I will then introduce thermocompression bonding technology [3], a method that allows us to further protect qubits from the environment and crosstalk. In particular, I will propose a new qubit design based on our experimental implementation of thermocompression bonded chips, where vacuum gap capacitors are used to reduce dissipation due to so-called two-level state (TLS) defects in amorphous dielectrics, which are the insulators presently used in our qubits. Finally, I will show a set of cleaning methods to further minimize TLS defects in resonators that allow us to reach quality factors in excess of two million at low power.

[1] J.H. Béjanin, T.G. McConkey... M.M., Three-Dimensional Wiring for Extensible Quantum Computing: The Quantum Socket, Phys. Rev. Applied 6, 044010 (2016)
[2] T.G. McConkey... M.M., Mitigating Leakage Errors due to Cavity Modes in a Superconducting Quantum Computer, Quantum Sci. Technol. 3, 034004 (2018)
[3] C.R.H. McRae... M.M., Thermocompression Bonding Technology for Multilayer Superconducting Quantum Circuits, Appl. Phys. Lett. 111, 123501 (2017)


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