Speaker
Description
Charges and spins confined in semiconductor quantum dots coupled to microwave photons provide a versatile platform for quantum computation and quantum optics, but coupling strengths are fundamentally limited by the weak electric dipole moment. In this context, heterostructures hosting low-dimensional carrier systems offer a promising route to scalable and tunable architectures.
Here, we investigate quantum dots defined in germanium quantum wells, where a high-mobility two-dimensional hole gas enables strong confinement and electrical control. By integrating these heterostructures with high-impedance granular aluminium superconducting resonators, we enhance the charge--photon interaction and achieve strong coupling.
The large kinetic inductance of granular aluminium allows us to realize resonators with characteristic impedances exceeding 20 k$\Omega$, significantly boosting the dipole coupling strength and overcoming a key limitation of semiconductor circuit quantum electrodynamics.
In parallel, we develop numerical electrostatic models of gate-defined quantum dots, enabling systematic optimization of device geometry via charge distributions, lever arms, and dipole moments. These simulations provide a predictive framework for engineering device performance.
The combination of materials engineering and simulation-guided design establishes a scalable approach to quantum device optimization, directly applicable to a broad class of low-dimensional material platforms.