Improvement of the superconducting qubit lifetime with the surface passivation technology
ORAL
Abstract
It is well known that the two-level systems (TLSs) existing in the amorphous surface/interface oxides of the metal pads are the main decoherence source of the superconducting quantum devices. There are a few ways to remove the surface oxides in order to improve the microwave loss; One of the straightforward methods is to encapsulate the metal pads with another low loss thin metal, such as Ta or TiN, which has less oxidation in the atmosphere. In this work, we present our measurements on the Nb-based superconducting transmon qubits with different surface passivation technologies. We clearly show the improvement of the qubit coherence if carefully choosing the encapsulating materials, which is indicative that the surface TLS losses are effectively suppressed with encapsulation. We benchmark the qubit energy relaxation and discuss the instabilities of the TLSs resonating near the qubit frequency.
*This material is based upon work supported by the U.S. Department of Energy, Office of Science, National Quantum Information Science Research Centers, Superconducting Quantum Materials and Systems Center (SQMS) under contract number DE-AC02-07CH11359.
–
Presenters
Shaojiang Zhu
Fermilab
Authors
Shaojiang Zhu
Fermilab
Mustafa Bal
Fermilab
Francesco Crisa
Fermilab
Akshay A Murthy
Fermilab
Fermi National Accelerator Laboratory
ZuHawn Sung
Fermilab
Jaeyel Lee
Fermilab
Daniel Bafia
Fermilab
Fermi National Accelerator Laboratory
David van Zanten
Fermilab
FermiLab
SQMS - Fermilab
Grigory Eremeev
Fermilab
Ivan Nekrashevich
Fermi National Accelerator Laboratory
Fermilab
Fermi National Accelerator Laboratory, Batavia, IL 60510, USA
Roman Pilipenko
National Accelerator Laboratory
Fermilab
Fermi National Accelerator Laboratory
Anna Grassellino
Fermilab
Alexander Romanenko
Fermilab
Florent Q Lecocq
National Institute of Standards and Technology, Boulder
National Institute of Standards and Technology
National Institute of Science and Technology
Michael R Vissers
NIST Boulder
National Institute of Standards and Technology, Boulder
NIST
National Institute of Standards and Technology
National Institute of Standards and Technology Boulder
Joel N Ullom
National Institute of Standards and Technology Boulder
National Institute of Standards and Technology
Jose Aumentado
National Institute of Standards and Technology Boulder
National Institute of Standards and Technology
Peter Hopkins
National Institute of Standards and Technology Boulder
