2013/11/26 by Matthew T. Bell, M. T. Bell, Joshua Paramanandam +4
Computer Science · Physics and Astronomy · #Condensed matter physics #Excited state #Ground state #Josephson effect #Physics #Quantum #Quantum Computing Algorithms and Architecture #Quantum Information and Cryptography #Quantum and electron transport phenomena #Quantum mechanics #Qubit #Rhombus #Superconductivity #cond-mat.mes-hall #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.112.167001
published as Phys. Rev. Lett. 112, 167001 (2014) · 5 pages, 4 figures, Supplementary Materials
arxiv created 2013/11/26 · openalex publication_date 2014/04/25 · arxiv updated 2016/03/16 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We have studied the low-energy excitations in a minimalistic protected Josephson circuit which contains two basic elements (rhombi) characterized by the π periodicity of the Josephson energy. Novel design of these elements, which reduces their sensitivity to the offset charge fluctuations, has been employed. We have observed that the lifetime T1 of the first excited state of this quantum circuit in the protected regime is increased up to 70 μs, a factor of ∼100 longer than that in the unprotected state. The quality factor ω01T1 of this qubit exceeds 106. Our results are in agreement with theoretical expectations; they demonstrate the feasibility of symmetry protection in the rhombus-based qubits fabricated with existing technology.