Superconducting phase qubits with shadow-evaporated Josephson junctions
| Autor: | Xiaobo Zhu, Ye Tian, Hui Deng, Shi-Ping Zhao, Dongning Zheng, Feifan Su, Li Lv, Weiyang Liu, Huikai Xu, Zhi-Yuan Li |
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| Rok vydání: | 2017 |
| Předmět: |
Josephson effect
Physics Condensed matter physics Dephasing General Physics and Astronomy Quantum Physics 02 engineering and technology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect 021001 nanoscience & nanotechnology 01 natural sciences law.invention Phase qubit Pi Josephson junction SQUID law Condensed Matter::Superconductivity Qubit 0103 physical sciences Superconducting tunnel junction 010306 general physics 0210 nano-technology Superconducting quantum computing |
| Zdroj: | Chinese Physics B. 26:060308 |
| ISSN: | 1674-1056 |
| Popis: | We develop a fabrication process for the superconducting phase qubits in which Josephson junctions for both the qubit and superconducting quantum interference device (SQUID) detector are prepared by shadow evaporation with a suspended bridge. Al junctions with areas as small as are fabricated for the qubit, in which the number of the decoherence-causing two-level systems (TLS) residing in the tunnel barrier and proportional to the junction area are greatly reduced. The measured energy spectrum shows no avoided crossing arising from coherent TLS in the experimentally reachable flux bias range of the phase qubit, which demonstrates the energy relaxation time T 1 and dephasing time on the order of 100 ns and 50 ns, respectively. We discuss several possible origins of decoherence from incoherent or weakly-coupled coherent TLS and further improvements of the qubit performance. |
| Databáze: | OpenAIRE |
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