Dephasing of Si spin qubits due to charge noise

TL;DR

This paper investigates how charge noise from traps near silicon quantum dots causes decoherence in spin qubits, quantifying its effects on gate errors and dephasing using realistic noise models.

Contribution

It provides a detailed analysis of charge noise effects on silicon spin qubits, including models for both telegraph and 1/f noise, and estimates their impact on qubit coherence.

Findings

Charge traps induce significant dephasing in Si spin qubits.

Noise models predict gate errors and decoherence rates.

Quantitative estimates inform qubit design and error mitigation.

Abstract

Spin qubits in Silicon quantum dots can have long coherence times, yet their manipulation relies on the exchange interaction, through which charge noise can induce decoherence. Charge traps near the interface of a Si heterostructure lead to fluctuations in the quantum-dot confinement and barrier potentials, which cause gating errors and two-spin dephasing. We quantify these effects in Si double quantum dots using a realistic model of noise. Specifically, we consider both random telegraph noise from a few traps (good for dots grown on submicron wafers) and 1/f noise from many traps (good for larger wafers appropriate for quantum dot arrays). We give estimates of gate errors for single-spin qubit architectures and dephasing in singlet-triplet qubits.