The HQC group recently demonstrated the manipulation, with cavity photons, of quantum states in a carbon nanotube (CNT) with coherence time of the order of 1.3μs. This is 2 orders of magnitude larger than any previous implementation of spin qubits with CNT and 1 order of magnitude larger than similar device using silicon. The proposed internship, and following PhD, aims at pushing these recent results further to demonstrate a high single-qubit gate fidelity above the fault-tolerant threshold for quantum error correction codes (and go to two-qubit gates). The strategy will rely on electrically tuning the spin qubit to further improve its coherence time (expected to be between 5μs and 25μs), boosting the spin-photon coupling with high-kinetic inductance microwave resonators and exploiting novel electron-photon coupling schemes that are currently being demonstrated in the group. The candidate will benefit from the interaction with all members of the group and of the fruitful partnership we have with the startup C12 which can then offer a CIFRE PhD funding. The candidate should have a strong theoretical background in quantum and condensed matter physics, a strong interest in nano-devices and complex microwave techniques to manipulate a quantum system in the time domain.