Distinguishing Coherent and Thermal Photon Noise in a Circuit Quantum Electrodynamical System
| Autor: | David Kim, Simon Gustavsson, Adam Sears, Jonilyn Yoder, Terry P. Orlando, Daniel Campbell, Fei Yan, Philip Krantz, Andrew J. Kerman, David Hover, William D. Oliver, Morten Kjaergaard |
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| Rok vydání: | 2018 |
| Předmět: |
Physics
Flux qubit Photon Dephasing Attenuation Physics::Optics General Physics and Astronomy 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Noise (electronics) Computational physics symbols.namesake Stark effect Thermal radiation Qubit 0103 physical sciences symbols 010306 general physics 0210 nano-technology |
| Zdroj: | Physical review letters. 120(26) |
| ISSN: | 1079-7114 |
| Popis: | In the cavity-QED architecture, photon number fluctuations from residual cavity photons cause qubit dephasing due to the ac Stark effect. These unwanted photons originate from a variety of sources, such as thermal radiation, leftover measurement photons, and cross talk. Using a capacitively shunted flux qubit coupled to a transmission line cavity, we demonstrate a method that identifies and distinguishes coherent and thermal photons based on noise-spectral reconstruction from time-domain spin-locking relaxometry. Using these measurements, we attribute the limiting dephasing source in our system to thermal photons rather than coherent photons. By improving the cryogenic attenuation on lines leading to the cavity, we successfully suppress residual thermal photons and achieve T_{1}-limited spin-echo decay time. The spin-locking noise-spectroscopy technique allows broad frequency access and readily applies to other qubit modalities for identifying general asymmetric nonclassical noise spectra. |
| Databáze: | OpenAIRE |
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