Intitulé de l'offre : PhD: Quantum coherence of nanomechanical resonators at sub-mK temperatures (M/W) (H/F)
Référence : UPR2940-ELOBER-089
Nombre de Postes : 1
Lieu de travail : GRENOBLE
Date de publication : lundi 4 septembre 2023
Type de contrat : CDD Doctorant/Contrat doctoral
Durée du contrat : 36 mois
Date de début de la thèse : 1 janvier 2024
Quotité de travail : Temps complet
Rémunération : 2 135,00 € gross monthly
Section(s) CN : Condensed matter: electronic properties and structures
Description du sujet de thèse
The unparalleled sensitivity of quantum sensors promises a plethora of important applications. In particular, resonators with mechanical coherence times of order 10 to 100 milliseconds at 10 mK have recently been demonstrated. These devices could be used as quantum memories in hybrid systems for quantum communication and computation. They could also be used for testing fundamental aspects of quantum mechanics. At the same time, nuclear demagnetization refrigeration (NDR), yielding microkelvin cryostat temperatures, has been applied to microwave optomechanics, yielding passive ground state cooling of ~10 MHz mechanical modes. However, researchers in these two fields have not yet combined NDR with functionalized ultra-high Q mechanical resonators with mechanical coherence times exceeding 10 ms. Since the mechanical linewidth Γ_m of these devices increases with temperature even at 10 mK, present experiments appear to lack the full potential mechanical coherence time 1/(Γ_m n_th ) for thermal phonon occupation n_th that can be achieved by cooling to lower bath temperatures. We will use state-of-the-art optomechanical devices that are known to have exceptionally low mechanical dissipation near 10 mK. Using the microkelvin microwave optomechanics cryostats of the Néel Ultra-Low Temperatures group, which are unique in the world, we will cool the devices to temperatures below 1 mK in order to achieve a record mechanical quantum coherence time of 1 second.
The candidate should be highly motivated to tackle challenging problems in experimental low temperature physics.
Furthermore, he should have a strong theoretical background in quantum mechanics and solid-state physics. In particular, experience with cryogenic measurements, automated data acquisition, clean room work and fluent English.
Contexte de travail
The Institut NÉEL is a CNRS unit (UPR 2940) under agreement with the University Grenoble Alpes.
The Institut Néel is a condensed matter physics laboratory in Grenoble. It consists of 450 employees, including 175 researchers. The research activities are centered on fundamental condensed matter physics and also include some chemistry, engineering and life sciences. The Institute possesses technological expertise at the highest level, which is crucial for research projects carried out here. While the research is primarily experimental, it also relies on strong abilities in analytical and numerical theoretical physics.
Host research group: Ultra-low temperautres (MCBT-Institut Néel)
Le poste se situe dans un secteur relevant de la protection du potentiel scientifique et technique (PPST), et nécessite donc, conformément à la réglementation, que votre arrivée soit autorisée par l'autorité compétente du MESR.
Contraintes et risques
The main risks are associated with cryogenic fluids.