1 research outputs found
Decoherence of floating qubits due to capacitive coupling
It has often been assumed that electrically floating qubits, such as flux
qubits, are immune to decoherence due to capacitive coupling. We show that
capacitive coupling to bias leads can be a dominant source of dissipation, and
therefore of decoherence, for such floating qubits. Classical electrostatic
arguments are sufficient to get a good estimate of this source of relaxation
for standard superconducting qubit designs. We show that relaxation times can
be improved by designing floating qubits so they couple symmetrically to the
bias leads. Observed coherence times of flux qubits with varying degrees of
symmetry qualitatively support our results.Comment: V1: 4 pages, 3 figures. V2: 5 pages, 3 figures. Published versio