2017/11/30 by Christina Knapp, Torsten Karzig, Roman Lutchyn +1 · 2 citations
Physics and Astronomy · #cond-mat.mes-hall #cond-mat.supr-con #quant-ph
paper · pdf · doi:10.1103/physrevb.97.125404
published as Phys. Rev. B 97, 125404 (2018) · 15 pages, 2 figures, v3: corrected thermal quasiparticle dephasing time
arxiv created 2018/05/22 · arxiv updated 2018/05/23
We analyze charging-energy-protected Majorana-based qubits, focusing on the residual dephasing that is present when the distance between Majorana zero modes (MZMs) is insufficient for full topological protection. We argue that the leading source of dephasing is 1/f charge noise. This noise affects the qubit as a result of the hybridization energy and charge distribution associated with weakly-overlapping MZMs, which we calculate using a charge-conserving formalism. We estimate the coherence time to be hundreds of nanoseconds for Majorana-based qubits whose MZM separation is L∼ 5ξ (with ξ being the coherence length). The coherence time grows exponentially with MZM separation and eventually becomes temperature-limited for L/ξ∼ 30.