2020/12/14 by M. Virginia P. Altoé, Altoé, M. Virginia P., Archan Banerjee +40 · 2 citations
Computer Science · Engineering · Physics and Astronomy · #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Mechanical and Optical Resonators #Photonic and Optical Devices #Quantum Information and Cryptography #Quantum Physics (quant-ph) #cond-mat.mtrl-sci #quant-ph
paper · pdf · doi:10.48550/arxiv.2012.07604
10 pages, 3 figures, supplemental information 10 pages, 11 figures
arxiv created 2020/12/14 · openalex publication_date 2020/12/14 · arxiv updated 2020/12/15 · openalex created_date 2023/01/04 · openalex updated_date 2026/07/28
Quantum sensing and computation can be realized with superconducting microwave circuits. Qubits are engineered quantum systems of capacitors and inductors with non-linear Josephson junctions. They operate in the single-excitation quantum regime, photons of 27 μeV at 6.5 GHz. Quantum coherence is fundamentally limited by materials defects, in particular atomic-scale parasitic two-level systems (TLS) in amorphous dielectrics at circuit interfaces.[1] The electric fields driving oscillating charges in quantum circuits resonantly couple to TLS, producing phase noise and dissipation. We use coplanar niobium-on-silicon superconducting resonators to probe decoherence in quantum circuits. By selectively modifying interface dielectrics, we show that most TLS losses come from the silicon surface oxide, and most non-TLS losses are distributed throughout the niobium surface oxide. Through post-fabrication interface modification we reduced TLS losses by 85% and non-TLS losses by 72%, obtaining record single-photon resonator quality factors above 5 million and approaching a regime where non-TLS losses are dominant. [1]Müller, C., Cole, J. H. & Lisenfeld, J. Towards understanding two-level-systems in amorphous solids: insights from quantum circuits. Rep. Prog. Phys. 82, 124501 (2019)