LKB - Polarised Helium, Quantum Fluids and Solids


MRI - Liquid NMR - Polarising ³He - Quantum gases

  The group pursues theoretical, experimental, and applied research, drawing on long-standing knowledge of quantum fluids (bosons and fermions) and on expertise in optical pumping, production and handling of high nuclear polarisation in helium-3, and NMR in hyperpolarised systems (at low or high magnetic field, in liquid or gas phase).

Selected publicationsCollaborations

MARGIN (2020-2022, ANR-RSF) mainly deals with MAgnetic Resonance studies of Gas diffusion In Nanoporous materials. Investigations focus on  of the influence of gas-wall interactions on NMR diffusion measurements.

Partnership: LKB (Coord.: P.-J. Nacher)  – MRSLab, KFU (Coord.: M. Tagirov).

Summary  Résumé  Project overview  Go to project homepage

HELPING (2021-2025, ANR) is devoted to High field Enhancement of nucLear Polarisation In Noble Gases. Workplan includes in-depth studies with spin-1/2 isotopes (3He, 129Xe) and tests with spin-3/2 isotopes (83Kr, 21Ne), as well as proof-of-concept experiments in MRS, MRI, or NMR magnetomertry.

Partnership: LKB (Coord.: G. Tastevin)  – NIMBE, CEA Saclay (Sc. Lead.: G. Huber).

Summary  Résumé Go to project homepage


Regular article

The outcomes of measurements in the de Broglie–Bohm theory, Tastevin G., Laloë F., C. R. Physique (2021) 22(1):99-116


Within the de Broglie–Bohm (dBB) theory, the measurement process and the determination of itsoutcome are usually discussed in terms of the effect of the Bohmian positions of the measured system S. Thisarticle shows that the Bohmian positions associated with the measurement apparatus M can actually play acrucial role in the determination of the result ofmeasurement. Indeed, inmany cases, the result is practicallyindependent of the initial value of a Bohmian position associated with S, and determined only by those ofM. The measurement then does not reveal the value of any pre-existing variable attached to S, but just theinitial state of the measurement apparatus. Quantum contextuality then appears with particular clarity as aconsequence of the dBB dynamics for entangled systems.

Regular article

Nuclear hyperpolarization of ³He by magnetized plasmas, Maul A., Blümler P., Nacher P.-J., Otten E., Tastevin G., and Heil W.
Phys. Rev. A (2018) 98, 063405 [12 pages]


Regular article

Regular article

Doppler-free spectroscopy of the lowest triplet states of helium using double optical resonance, A. Dia, M. Abboud, P.-J. Nacher, and G. Tastevin – Eur. Phys. J. D (2021) 75:223SharedIt link


Optical pumping on the 2³S-2³P transition (1083 nm) of metastable ³He or 4He atoms is used for scienceand applications. We report on its combination with an optical probe on the 2³P-3³S transition (706.5 nm) ina ladder-type double optical resonance scheme, with cw single-frequency pump and probe diode lasers. Theoreticalexpectations for level structure and absorption spectra were computed for both isotopes. Narrow Doppler-free spectrallines were experimentally obtained in low-pressure gas samples. The line weights and their Zeeman structure in weakmagnetic eld agreed with expectations. The precision of the line positions and line splittings was limited by genericerrors of our commercial Fizeau wavemeter, which were independently characterised. The potential of this doubleresonance scheme for spectroscopic measurements on the three lowest triplet states of He was evaluated. The relevanceof velocity- and sublevel-selective pumping combined with polarisation spectroscopy of probe absorption for a studyof pressure-dependent population transfers in the 2³P state was established.

Regular article

Surrealistic Bohmian trajectories do not occur with macroscopic pointers

Eur. Phys. J. D (2018) 72: 183

Tastevin G. and Laloë F.


We discuss whether position measurements in quantum mechanics can be contradictory with Bohmian trajectories, leading to what has been called “surrealistic trajectories” in theliterature. Previous work has considered that a single Bohmian position can be ascribed to the pointer. Nevertheless, a correct treatment of a macroscopic pointer requires that many particle positions should be included in the dynamics of the system, and that statistical averages should be made over their random initial values. Using numerical as well as analytical calculations, we show that these surrealistic trajectories exist only if the pointer contains a small number of particles; they completely disappear with macroscopic pointers.With microscopic pointers, non-local effects of quantum entanglement can indeed takeplace and introduce unexpected trajectories, as in Bell experiments; moreover, the initialvalues of the Bohmian positions associated with the measurement apparatus may influencethe trajectory of the test particle, and determine the result of measurement. Nevertheless,a detailed observation of the trajectories of the particles of the pointer reveals the nature ofthe trajectory of the test particle; nothing looks surrealistic if all trajectories are properlyinterpreted.

Review article

Optically polarized ³He, T. R. Gentile, P. J. Nacher, B. Saam, and T. G. Walker

Rev. Mod. Phys. 89, 045004 (2017)


This article reviews the physics and technology of producing large quantities of highly spin-polarized ³He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized ³He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.


Comprenons-nous vraiment la mécanique quantique ?

Franck Laloë

EDP Sciences – Collection : Savoirs Actuels – 2nd edition – January 2018


Book chapter

History and physical principles of MRI

by M. E. Hayden and P.-J. Nacher.

Magn. Reson. Imaging Handbook, 1 – CRC press, 2016  (Ed. Luca SABA)




High Field Enhancement of nucLear Polarisation In Noble Gases.

CEA Saclay – Iramis – NIMBE – LSDRM
(H. Desvaux , P. Berthault, G. Huber, C. Boutin)
Collaborative Research Project, 2021-2025, ANR.
Partners: LKB (Paris) and NIMBE (CEA Saclay)

Prior collaborations:
– A superwide-bore MRI/MRS instrument for innovative concepts and applications
WideNMR (DIM Ile de France, 2016-2018).

– Non linear NMR in highly magnetised liquids
DIPOL (ANR – PRC Blanc, 2007-2011), IMAGINE (ANR – PRCI Blanc, 2013-2016).

  ILL Grenoble
(S. Pethukov, D. Jullien)
Neutron spin filters, massive production of hyperpolarised gas.
NMI3 Network under FP6.

(L. Darrasse, G. Guillot, X. Maitre; Z. Mokhtari)
Lung MRI, MRI methodology, on-site hyperpolarisation in clinical environment.
ACI project, PHIL and PHeLINet networks. CNRS (DEFI) project, HyperMRIHyperpolarisation « Brute force » multinoyaux pour l’IRM métabolique ciblée, DEFI Instrumentation aux Limites, 2018.

Fondation Pierre-Gilles de Gennes pour la Recherche
Transdisciplinary research in life sciences.
Research foundation (RTRA, 2009 – …) IMAGIV  Research network for in-vivo imaging (CNRS – GDR3271, 2009-2013, dir.: L. Darrasse)

DIPOL Non linear NMR in spin polarised liquids Colloborative reseach project (ANR – International Blanc Programme, 2007-2011)

 ONERA Palaiseau – DMPH/CMT (N. Zahzam) Optical gyro/magnetometry. Co-supervised PhD thesis (G. Renon, 2011-2014)

GDR (French research network) : Gaz rares hyperpolarisés From optical pumping techniques to applications in NMR. (CNRS – GDR2144, 2004-2008, dir. : Y. Cremillieux)


MAgnetic Resonance studies of Gas diffusion in Nanoporous materials

France – Russian Federation (International Collaborative Research Project, 2020-2023, ANR-RSF)
Partners: LKB (Paris) and MRS lab. (Kazan Federal University)

NMR Investigations of Magnetisation-Induced Non-linear Effects

French-Austrian research project (ANR, international Blanc Programme, 2013-2016)
Partners: LSDRM/NIMBE/IRAMIS at CEA (Saclay), Institute of Organic Chemistry at J. Kepler University (Linz), LKB (Paris), and RS²D company (Strasbourg).

   Mainz University, Germany (Pr W. Heil)
³He optical pumping, lung MRI, neutron spin filters.
Several Procope bilareal programs.
European projects PHIL and PHeLINet.
Co-supervised PhD thesis (M. Batz, 2011).
Shared awards:
Körber European Science Award 1998
Magnetic Resonance Tomography with Helium-3
Werner Heil (Mainz), Michèle Leduc (LKB), Ernst W. Otten (Mainz), Manfred Thelen (Mainz).
IBA-Europhysics Prize 2005 for Applied Nuclear Science and Nuclear Methods in Medicine (EPS Nuclear Physics Division)
Development of spin polarized ³He targets by optical pumping and their applications in nuclear science and medicine: nuclear physics, neutron low temperature physics and medicine.
Werner Heil (J. Gutenberg Univ. Mainz) and Pierre-Jean Nacher (Lab. Kastler Brossel, ENS Paris).

University of Winnipeg, Canada (C. Bidinosti)
Low field NMR and MRI, ³He lung MRI.


Université Saint Joseph de Beyrouth
(M. Abboud Mehanna)
Metastability exchange optical pumping of ³He: collisional processes.
Co-supervised PhD thesis (A. Dia, 2021).


Krakow University, Poland (Pr T. Dohnalik, Pr Z. Olejniczak)
High-field 3He optical pumping, on-site hyperpolarisation, low-field lung MRI, detection of He2* molecules.
PICS and Polonium programs; co-supervised PhD thesis (B. Glowacz, 2011)

 Simon Fraser University, Canada (Pr M. Hayden)
Liquid NMR, hyperpolarised gases, MRI, 3He low temperature physics.

European Network for Hyperpolarization Physics and Methodology in NMR and MRI
Research network (European Community – FP7- MPNS: “Materials, Physics and Nanosciences” – COST Action TD1103, 2011-2015).

 PHeLINet Polarised Helium Lung Imaging Network
Research network (European Community – FP6- RTN Marie-Curie, 2007-2011)

Polarized Helium to Image the Lung
Research network (European Community – FP5 – RTD – Quality of life, 2000-2004, coord.: LKB )

Integrated Infrastructure Initiative for Neutron Scattering and Muon Spectroscopy-Joint Research Activity: 3He Neutron Spin Filters
Access Programme (European Community – FP6, 2004-2008)