Limitations of the $g$-tensor formalism of semiconductor spin qubits

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Hauptverfasser: György, Zoltán, Pályi, András, Széchenyi, Gábor
Format: Preprint
Veröffentlicht: 2025
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author György, Zoltán
Pályi, András
Széchenyi, Gábor
author_facet György, Zoltán
Pályi, András
Széchenyi, Gábor
contents The $g$-tensor formalism is a powerful method for describing the electrical driving of semiconductor spin qubits. However, up to now, this technique has only been applied to the simplest qubit dynamics, resonant monochromatic driving by a single gate. Here we study the description of (i) monochromatic driving using two driving gates and bichromatic driving via (ii) one or (iii) two gates. Assuming a general Hamiltonian with qubit states well separated from excited orbital states, we find that when (i) two driving gates are used for monochromatic driving or (ii) a single one for bichromatic, the $g$-tensor formalism successfully captures the leading-order dynamics. We express the Rabi frequency and the Bloch-Siegert shift using the $g$-tensor and its first and second derivatives with respect to the gate voltage. However, when (iii) bichromatic driving is realized using two distinct driving gates, we see a breakdown of $g$-tensor formalism: the Rabi frequency cannot be expressed using the $g$-tensor and its derivatives. We find that beyond the $g$-tensor and its derivatives, three additional parameters are needed to capture the dynamics. We demonstrate our general results by assuming an electron (hole) confined in a circular quantum dot, subjected to Rashba spin-orbit interaction.
format Preprint
id arxiv_https___arxiv_org_abs_2504_05749
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Limitations of the $g$-tensor formalism of semiconductor spin qubits
György, Zoltán
Pályi, András
Széchenyi, Gábor
Mesoscale and Nanoscale Physics
Quantum Physics
The $g$-tensor formalism is a powerful method for describing the electrical driving of semiconductor spin qubits. However, up to now, this technique has only been applied to the simplest qubit dynamics, resonant monochromatic driving by a single gate. Here we study the description of (i) monochromatic driving using two driving gates and bichromatic driving via (ii) one or (iii) two gates. Assuming a general Hamiltonian with qubit states well separated from excited orbital states, we find that when (i) two driving gates are used for monochromatic driving or (ii) a single one for bichromatic, the $g$-tensor formalism successfully captures the leading-order dynamics. We express the Rabi frequency and the Bloch-Siegert shift using the $g$-tensor and its first and second derivatives with respect to the gate voltage. However, when (iii) bichromatic driving is realized using two distinct driving gates, we see a breakdown of $g$-tensor formalism: the Rabi frequency cannot be expressed using the $g$-tensor and its derivatives. We find that beyond the $g$-tensor and its derivatives, three additional parameters are needed to capture the dynamics. We demonstrate our general results by assuming an electron (hole) confined in a circular quantum dot, subjected to Rashba spin-orbit interaction.
title Limitations of the $g$-tensor formalism of semiconductor spin qubits
topic Mesoscale and Nanoscale Physics
Quantum Physics
url https://arxiv.org/abs/2504.05749