Doctorat (M/F) - circuits quantiques hybrides

Job Description

Thesis Subject

A quantum memory allows for the simultaneous storage of a large number of quantum states and can reduce the qubit overhead of a quantum processor. Ensembles of electron spins coupled to a resonator are a promising candidate for storing propagating microwave states: spin species with long coherence times ensure durable storage, while an inhomogeneously broadened spectral line allows for the addressing of numerous spectral and temporal modes within a single device. Storage efficiency is determined by the coupling between the ensemble and the superconducting resonator used to address it. The ensembles proposed to date rely on crystalline matrices, in which spin density, the nuclear environment, and geometry are fixed during the growth process.
This project replaces the crystal with a deposited molecular film. The spin is implemented via a molecule: its nuclear environment is defined during synthesis, its concentration is determined by mass, and it is integrated onto a pre-fabricated superconducting chip via drop-casting or spin-coating. This thesis will explore several candidates: perchlorotriphenylmethyl and tetrathiatriarylmethyl (trityl) radicals—which exhibit a narrow spectral line and, when isotopically labeled, an addressable nuclear spin—as well as lanthanide complexes, such as Lu(II) or Yb(III) species, whose hyperfine structure offers "clock transitions." Both families combine the potential for long coherence times with structural properties compatible with strong coupling to a planar resonator.
The work will involve measuring the coherence of the selected candidates at millikelvin temperatures—a regime in which none of them have yet been characterized—as well as their coupling to a low-impedance resonator designed to maximize interaction with the spins. The objective of this thesis is a quantitative assessment of the capacity of these molecular spins to reach the regime required for a microwave quantum memory.

Expected knowledge:
* Physical sciences (superconductivity, low temperatures, experimental setups, magnetic resonance)
* High-frequency microwave engineering
* Nanofabrication

Operational skills:
* Expertise in high-frequency microwave measurements
* Scientific computing
* Software engineering (proficiency in Python, Git)
* Ability to work independently

Your Work Environment

Integration into the 'Quantum Circuits' research group within the Physics Laboratory at ENS de Lyon. Access provided to numerical tools, nanofabrication facilities, and cryogenic equipment.

Constraints and risks

None

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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