High impedance circuit quantum electrodynamics with hole spins

本计画将从实验与理论上研究半导体奈米结构中的洞自旋所组成的混合量子系统，并将其嵌入高阻抗超导共振器中。 一方面，硅和锗（SiGe）中空穴的长自旋相干时间与它们的稀核自旋系统相结合，另一方面，高阻抗颗粒铝（grAl）谐振器，代表了一个独特的平台，以研究在腔量子电动力学（QED）意义上的单个自旋到单个玻色子模式的强耦合。 在这种情况下，这是一个有趣的开放的问题，是否以及在何种程度上的锗的价带中的强自旋-轨道相互作用可以引起一个诱导的电偶极耦合的自旋的电场的超导谐振器。 近期的目标是在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。 在项目的最后，我们的目标是达到一个空穴自旋和一个单光子之间的强耦合腔QED制度。 我们将开发一个理论模型，描述的混合系统的SiGe量子点耦合到一个高阻抗谐振器中的孔组成，并计算微波腔传输，包含有关自旋光子耦合的信息。一个长期的目标是研究通过超导谐振器中虚微波光子的交换耦合两个远程空穴自旋的可能性。

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.