Pushing the qubits temperature limit with disordered Superconductors
Quantum information science is rapidly advancing through the development of various technological platforms like spin-qubits, trapped ions, neutral atoms and superconducting qubits. The latter arguably achieved the most advanced quantum processor[1] thanks to its famous Transmon qubit[2]. In these superconducting quantum chips, control and readout are performed via microwave photons. Nowadays, most qubits are based on aluminum Josephson junctions, however aluminum has a small superconducting gap Δ≈1K and critical magnetic field≈10mT. These material properties are constraining the use of superconducting qubits to ultra-low temperature <100mK and near zero magnetic field. Extending these temperature and magnetic field constraints could be a clear asset for quantum processor, sensing and signal processing. To allow qubit operation up to 1K and 1T, we envision to make qubit from niobium nitride (NbN), a disordered superconductor[3]. Indeed, NbN has a superconducting gap of ≈10K and has a bulk critical field largely above 10T.
Project Objective: As a first step toward NbN qubit, you will design and fabricate NbN nanojunctions. You will perform room temperature and cryogenics DC characterizations to test their temperature and magnetic field resilience. Then, based on this work, you will model and design a RF quantum chip, around a NbN nano-junctions and assess its potential as a qubit in a state-of-the-art RF cryogenics sample.
Research Environment: As an intern, you will join the LATEQS team, a vibrant group of 30 researchers including 15 PhD students, and be fully integrated into our daily research activities Our group plays an active role in the French national “Plan Quantique” and in the PEPR Quantum Technologies project “RobustSuperQ”. This internship offers the opportunity to work at the forefront of quantum technology research, with access to world-class facilities and expertise.
Career Perspective: This internship can naturally evolve into a PhD project within our team.
[1] Nature 638, 920—926 (2025)
[2] Phys. Rev. A 76, 042319 (2007)
[3] Appl. Phys. Lett. 119, 054001 (2021)