Quantum computing is currently pushing further the frontier of information technology. Among other fields, solid-state hole-spin qubits are a promising research area. Recently, we reached the strong-coupling regime between the spin of a single hole trapped inside the channel of a silicon transistor and a single microwave photon enclosed in a superconducting resonator [1], realizing a hybrid spin cQED architecture. The aim of this project is to further increase the coupling strength between the hole spin and the microwave photon to reach the ultra-strong coupling regime, a regime of light-matter interaction largely unexplored. First, we will probe this unique quantum system via microwave spectroscopy measurements [2]. In parallel, we will explore how time-domain experiments can unlock the peculiar physics of an ultra-strongly coupled spin to a microwave photon [3, 4]. Our research team is part of the French national “Plan Quantique” and we strongly collaborate with in-house theory colleagues. During the master project, you will collaborate on a daily basis with a lively team of three permanent researchers and three PhDs. You will participate to the development of new samples and you will learn to cool down samples to reach cryogenic temperatures. State-of-the-art DC and RF measurements will be used. [1] Nat. Nano 18, 741, 2023 [2] Phys. Rev. A 75, 032329, 2007 [3] Nat. Rev Phys. 1, 19, 219 [4] Rev. Mod. Phys. 91, 025005, 2019