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arXiv · 1711.03968

Dephasing of Majorana-based qubits

Christina Knapp·Torsten Karzig·Roman Lutchyn·Chetan Nayak
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Abstract

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 $L\sim 5ξ$ (with $ξ$ being the coherence length). The coherence time grows exponentially with MZM separation and eventually becomes temperature-limited for $L/ξ\sim 30$.

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Christina Knapp, Torsten Karzig, Roman Lutchyn, Chetan Nayak. 2018-05-22. Dephasing of Majorana-based qubits. https://doi.org/10.1103/physrevb.97.125404

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