High impedance circuit quantum electrodynamics with hole spins

该项目将从实验和理论上研究嵌入到高阻抗超导谐振器中的半导体纳米结构中由空穴自旋组成的混合量子系统。硅、锗(SiGe)空穴的长自旋相干时间及其稀核自旋系统与高阻抗颗粒铝(GRAL)谐振腔的结合，代表了在腔量子电动力学(QED)意义上研究单个自旋与单个玻色子模式强耦合的独特平台。在此背景下，Ge价带中强烈的自旋-轨道相互作用是否以及在多大程度上能够引起自旋与超导谐振器电场的感应电偶极耦合是一个有趣的悬而未决的问题。近期的目标将是在GRAL超导谐振器的帮助下实现单孔自旋的色散读出，这在适度的自旋-光子耦合下是现实的。在项目接近尾声时，我们的目标是达到空穴自旋与单光子之间的腔QED的强耦合区域。我们将建立一个描述由高阻抗谐振器耦合的SiGe量子点中的空穴组成的混合系统的理论模型，并计算包含自旋-光子耦合信息的微波腔传输。一个长期的目标是研究通过在超导谐振器中交换虚拟微波光子来耦合两个遥远的空穴自旋的可能性。

This project will experimentally and theoretically investigate hybrid quantum systems consisting of hole spins in semiconductor nanostructures that are embedded into high-impedance superconducting resonators. The combination of the long spin coherence times of holes in silicon and germanium (SiGe) with their dilute nuclear spin system on the one hand, and high-impedance granular aluminum (grAl) resonators on the other, represents a unique platform to investigate the strong coupling of individual spins to a single boson mode in the sense of cavity quantum electrodynamics (QED). In this context, it is an interesting open question whether and to what extent the strong spin-orbit interaction in the valence band of germanium can give rise to an induced electric dipole coupling of the spin to the electric field of the superconducting resonator. A near-term goal will be to achieve dispersive readout of single hole spins with the help of the grAl superconducting resonator, which is realistic with moderate spin-photon coupling. Towards the end of the project, we aim at reaching the strong coupling regime of cavity QED between a hole spin and a single photon. We will develop a theoretical model that describes the hybrid system consisting of holes in SiGe quantum dots coupled to a high-impedance resonator, and calculate the microwave cavity transmission that contains information about the spin-photon coupling. A long-term goal is to investigate the possibility of coupling two remote hole spins via the exchange of virtual microwave photons in the superconducting resonator.