2015/09/30 by Chen Wang, Christopher Axline, Yvonne Y. Gao +4 · 2 citations
Physics and Astronomy · #quant-ph #cond-mat.supr-con
paper · pdf · doi:10.1063/1.4934486
published as Appl. Phys. Lett. 107, 162601 (2015) · Main text: 5 pages 4 figures; Supplementary Materials: 6 pages 4 figures 1 table
arxiv created 2015/10/15 · arxiv updated 2015/10/30
We study the energy relaxation times (T1) of superconducting transmon qubits in 3D cavities as a function of dielectric participation ratios of material surfaces. This surface participation ratio, representing the fraction of electric field energy stored in a dissipative surface layer, is computed by a two-step finite-element simulation and experimentally varied by qubit geometry. With a clean electromagnetic environment and suppressed non-equilibrium quasiparticle density, we find an approximately proportional relation between the transmon relaxation rates and surface participation ratios. These results suggest dielectric dissipation arising from material interfaces is the major limiting factor for the T1 of transmons in 3D cQED architecture. Our analysis also supports the notion of spatial discreteness of surface dielectric dissipation.