Characterization and Reduction of Capacitive Loss Induced by Sub-Micron Josephson Junction Fabrication in Superconducting Qubits
| Autor: | Zijun Chen, Matthew Neeley, Rami Barends, Daniel Sank, Pedram Roushan, Amit Vainsencher, Austin G. Fowler, John M. Martinis, Chris Quintana, James Wenner, Josh Mutus, Brooks Foxen, Benjamin Chiaro, Andrew Dunsworth, R. Graff, Charles Neill, Yu Chen, B. Burkett, Evan Jeffrey, Julian Kelly, A. Megrant, Theodore White, E. Lucero |
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| Rok vydání: | 2017 |
| Předmět: |
Josephson effect
Superconductivity Quantum Physics Materials science Fabrication Physics and Astronomy (miscellaneous) business.industry Capacitive sensing Coplanar waveguide FOS: Physical sciences 02 engineering and technology Dielectric 021001 nanoscience & nanotechnology 01 natural sciences Capacitance law.invention Capacitor law Condensed Matter::Superconductivity 0103 physical sciences Optoelectronics 010306 general physics 0210 nano-technology business Quantum Physics (quant-ph) |
| DOI: | 10.48550/arxiv.1706.00879 |
| Popis: | Josephson junctions form the essential non-linearity for almost all superconducting qubits. The junction is formed when two superconducting electrodes come within $\sim$1 nm of each other. Although the capacitance of these electrodes is a small fraction of the total qubit capacitance, the nearby electric fields are more concentrated in dielectric surfaces and can contribute substantially to the total dissipation. We have developed a technique to experimentally investigate the effect of these electrodes on the quality of superconducting devices. We use $\lambda$/4 coplanar waveguide resonators to emulate lumped qubit capacitors. We add a variable number of these electrodes to the capacitive end of these resonators and measure how the additional loss scales with number of electrodes. We then reduce this loss with fabrication techniques that limit the amount of lossy dielectrics. We then apply these techniques to the fabrication of Xmon qubits on a silicon substrate to improve their energy relaxation times by a factor of 5. |
| Databáze: | OpenAIRE |
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