半导体自旋量子比特 $g$ 张量形式方法的局限性
摘要
The -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 -tensor formalism successfully captures the leading-order dynamics. We express the Rabi frequency and the Bloch-Siegert shift using the -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 -tensor formalism: the Rabi frequency cannot be expressed using the -tensor and its derivatives. We find that beyond the -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.
引用
@article{arxiv.2504.05749,
title = {Limitations of the $g$-tensor formalism of semiconductor spin qubits},
author = {Zoltán György and András Pályi and Gábor Széchenyi},
journal= {arXiv preprint arXiv:2504.05749},
year = {2025}
}
备注
20 pages, 4 figures