Precision Measurements and tests of fundamental physics with cold molecules

Post: Master internship in Experimental Molecular Physics
Location: Laboratoire de Physique des Lasers (LPL), CNRS-Univ Sorbonne Paris Nord, Villetaneuse, France
Team: Metrology, Molecules and Fundamental Tests (MMFT)
Advisors: Dr Benoît Darquié (
Dr Mathieu Manceau (
Contract: Fixed Term, 4-6 months, starting in Spring 2022
Precision Measurements and tests of fundamental physics with cold molecules
Internship description:

The master student will participate in the development of a new-generation molecular clock specifically designed for
precision vibrational spectroscopy of cold molecules in the gas phase. The proposed technology is at the forefront of
cold molecule research and frequency metrology, and opens possibilities for using polyatomic molecules to perform
tests of fundamental physics and explore the limits of the standard model. The apparatus will be used in the first place
for measuring the electroweak-interactions-induced tiny energy difference between enantiomers of a chiral molecule,
a signature of parity (left-right symmetry) violation, and a sensitive probe of dark matter.
Compared to atoms, molecular systems, owing to their numerous degrees of freedom, offer promising perspectives
for improving tests of fundamental physics and precision measurements in general. Molecules are increasingly being
used internationally for instance to test fundamental symmetries1, to measure fundamental constants2 or their variation in time3
, to search for dark matter4 , … Many of these experiments can be cast as measurements of resonance frequencies of molecular transitions  highlighting the importance of frequency metrology. They also require advanced manipulation techniques already standard for atoms: individual states addressing, high detection rates, long coherence times, cooling of internal and external degrees of freedom.

The master student will take an active role in various aspects of the initial developments of the experiment which constitute major steps in providing such techniques for molecules. She/he will:
– participate in the development of a novel cold molecule apparatus and:
– set up in an existing cryostat thermometry and gas injection elements for volatile molecular species as well
as for cold helium;
– set up the optical bench for ablation inside the cryostat of solid molecular targets with a pulsed YAG laser;
-set up the mid-infrared quantum cascade laser system at 6.4 µm to probe molecular vibrations in this spectral region;
– perform first Doppler limited absorption spectroscopy on well-chosen promising chiral organo-metallic species and
polycyclic aromatic hydrocarbons cooled to ~1 K in the cryostat after laser ablation.

Andreev et al, Nature 562, 355 (2018). 
Alighanbari et al, Nature 581, 152 (2020). 
Bagdonaite et al, Science 339,46 (2013). 
Gaul et al, Phys. Rev. Lett. 125, 123004 (2020).

frequency metrology, Ramsey interferometry, Doppler-free methods, precision measurements, parity violation, chiral molecules, molecular beams, buffer-gas cooling, cold molecules, frequency comb lasers, quantum cascade lasers, molecular physics, quantum physics, optics & lasers, vacuum, electronics, programming & simulation Relevant publications from the team:

Santagata et al, Optica 6, 411 (2019); Cournol et al, Quantum Electron. 49, 288 (2019) ; Tokunaga et al, New J.
Phys. 19, 053006 (2017), arXiv:1607.08741 ; Argence et al, Nature Photon. 9, 456 (2015), arXiv:1412.2207

The applicant should be doing its master studies in a relevant area of experimental physics or chemical physics: atomic, molecular and optical physics, spectroscopy, lasers, quantum optics. He/She will be expected to display the initiative and creativity, together with the appropriate skills and knowledge, required to meet the project goals. Interested applicants should email a CV, a brief description of research interests and the contact details of 2 referents to B. Darquié ( and/or M. Manceau (