Faites connaître cette offre !
Reference : UPR2940-LAUBOY-004
Workplace : GRENOBLE
Date of publication : Tuesday, November 23, 2021
Type of Contract : FTC Scientist
Contract Period : 24 months
Expected date of employment : 1 March 2022
Proportion of work : Full time
Remuneration : Between 2663 € and 3783 € according to experience
Desired level of education : PhD
Experience required : 1 to 4 years
We have recently cooled a nanomechanical resonator to sub-mK temperatures purely by good thermal coupling to the refrigerator, i.e., by passive cooling. In contrast to the optomechanical cooling techniques used by many other groups, our technique cools the phonon bath of the vibrating structure as well as the low energy excitations arising from atomic-scale disorder in the structure. As a result, the 15 MHz mechanical mode reaches its quantum ground state. We will now apply this technology to study fundamental physics, including wave function collapse models, quantum thermodynamics, and the nature of the low energy excitations that dominate the behavior of amorphous solids at low temperatures. In addition to fundamental concerns, the latter topic has practical applications considering the importance of
tunneling two level systems to the damping of nanomechanical resonators and the decoherence of superconducting qubits.
These experiments are carried out on our nuclear demagnetization cryostat reaching sub-mK temperatures and two dry dilution refrigerators. Our combination of mi-crowave optomechanical measurements with sub-mK temperatures is a unique capability. Our group is also developing a continuous nuclear demagnetization refrigerator, which will allow us to maintain sub-mK temperatures indefinitely in a
cryogen-free system. Activities of the postdoc will include installation and tests of a travelling wave parametric amplifier, which will greatly enhance the sensitivity of our measurements; measurement of the optomechanical devices at very low temperatures; possibly nanofabrication; and data analysis.
Cryogenics, automated data acquisition, vacuum technology, clean room work, SEM, FIB, UV and e-beam lithography, Labview, fluent English.
The Institut Néel, UPR 2940 of CNRS, is a condensed matter physics laboratory in Grenoble. It consists of 460 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)
Constraints and risks
The main risks are associated with cryogenic fluids.
We talk about it on Twitter!