PhD student: Quantum entanglement of mechanical oscillators (M/F)

Job Description

Thesis Subject

Similarly to a single atom, the motion of a massive, mesoscopic-scale mechanical resonator can behave quantum mechanically when cooled down to ultra-low temperatures. The study of quantum states of motion of such a system has both fundamental and practical interests: for testing quantum mechanics in systems beyond the few-particle ensembles, its interplay with gravitation; also in force sensing, or as a light-matter interface for the development of quantum communication networks, in particular for storing and transducing the quantum information.
A mechanical resonator such as the micrometer-sized disks fabricated in our team (picture below) also confines optical modes that strongly interact with the motion. Therefore, light provides a means to shape the quantum state of motion of such an object when it is prepared close to its ground state (the 'phonon vacuum') by adding or removing phonons one by one; it also probes the obtained states.

This internship/PhD thesis aims to realize multipartite quantum control, entanglement and superposition, in systems composed of several of these optomechanical resonators, either evanescently coupled or arranged in an interferometric configuration. This work will target in particular the generation of maximally-entangled GHZ states, of importance in quantum computing protocols, or N00N states, of interest for sensing with sub-standard quantum limit sensitivity and offering the possibility to explore the concept of nonlocal influence in quantum mechanics.

Your Work Environment

Materials and Quantum Phenomena laboratory (MPQ) is a joint research unit between the French National Center for Scientific Research (CNRS) and Université Paris Cité. The laboratory specializes in the study of frontier quantum materials and the development of novel quantum devices.

The LIght and MEchanics (LIME, https://mpq.u-paris.fr/en/lime-en/) team studies the interactions between light and miniature mechanical resonators (micro- or nanomechanical). The team addresses both fundamental questions (quantum behavior of mechanical systems, decoherence phenomena at mesoscopic scales), and applications, notably in the field of optical and mechanical sensors. Thanks to its strong nanotechnology background, LIME ventures into multidisciplinary fields involving semiconductors, fluidics, biophysics and the development of new types of microscopes.

The PhD student will join the quantum optomechanics activity in semiconductor microdisks and will benefit from an operational experimental environment for the project (optics, cryogenics, instrumentation), computing tools and access to the clean room of the laboratory.

Constraints and risks

The work will primarily focus on optical experiments (at low power) conducted at ultra-low temperatures (in a cryogenic environment). Cleanroom work is also planned. This 150-square-meter facility is equipped with all the necessary equipment for fabricating micro- and nano-devices: optical and electronic lithography, wet and dry etching, thin-film deposition, and characterization.
Travel planned to attend conferences to present research findings.

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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