Phonon-Induced Exchange Gate Infidelities in Semiconducting Si-SiGe Spin Qubits

• URL: http://arxiv.org/abs/2408.02742v2
• Date: Wed, 6 Nov 2024 14:12:09 GMT
• Title: Phonon-Induced Exchange Gate Infidelities in Semiconducting Si-SiGe Spin Qubits
• Authors: Matthew Brooks, Rex Lundgren, Charles Tahan,
• Abstract summary: fidelities of exchange operations with semiconductor double quantum dot spin qubits in a Si-SiGe heterostructure are considered. Results suggest that for elevated temperatures within 200-300 mK, exchange gate operations are not currently limited by bulk phonons.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: Spin-spin exchange interactions between semiconductor spin qubits allow for fast single and two-qubit gates. During exchange, coupling of the qubits to a surrounding phonon bath may cause errors in the resulting gate. Here, the fidelities of exchange operations with semiconductor double quantum dot spin qubits in a Si-SiGe heterostructure coupled to a finite temperature phonon bath are considered. By employing a master equation approach, the isolated effect of each spin-phonon coupling term may be resolved, as well as leakage errors of encoded qubit operations. As the temperature is increased, a crossover is observed from where the primary source of error is due to a phonon induced perturbation of the two electron spin states, to one where the phonon induced coupling to an excited orbital state becomes the dominant error. Additionally, it is shown that a simple trade-off in pulse shape and length can improve robustness to spin-phonon induced errors during gate operations by up to an order of magnitude. Our results suggest that for elevated temperatures within 200-300 mK, exchange gate operations are not currently limited by bulk phonons. This is consistent with recent experiments.

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