LKB - Polarised Helium, Quantum Fluids and Solids

Research

News and Events

Regular article

Optical measurement of the equation of state of bulk liquid helium-4 around 1 K, L. Djadaojee, J. Grücker, Phys. Rev. B 103, 144513 (2021) [5 pages]

Abstract

Using a stimulated Brillouin gain spectroscopy technique, we have measured the equation of state of bulk liquid helium-4 at 1 K between 0 and 10 bars. Our results are in very good agreement with previous measurements and with theoretical equations of state. However, our specific method allows one to determine it on space/timescales as narrow as 35 μm/190 ns. This technique is of particular interest for solving a remaining debate about the value of the homogeneous cavitation pressure of liquid 4He at T1 K.

Regular article

Archives

PhD student

Zeyuan ZHANG has joined the group on Feb. 2022. She actively contributes to the HELPING project.

The HELPING project (2021-2025)

High field Enhancement of nucLear Polarisation In Noble Gases.
LKB (Coord. G. Tastevin) – NIMBE (Sc. Lead. G. Huber).

Summary / RésuméRecruitment:
1 PhD (LKB)  – Closed
1 Post-Doc (NIMBE)  – Open

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]

Review article

Optically polarized ³He, T. R. Gentile, P. J. Nacher, B. Saam, and T. G. Walker, Rev. Mod. Phys. 89, 045004 (2017)

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) 75:223 – SharedIt link

Abstract

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

The outcomes of measurements in the de Broglie-Bohm theory., G. Tastevin and F. Laloë – Comptes-Redus Acad Sci. France 22, 99 (2021) – arXiv:2102.02519

Abstract

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

PhD defense

Ali DIA gradutated from ENS-PSL (Paris) and USJ (Beyrouth) on May 7, 2021.
Experimental study of redistribution and exchange collisions in the 2³P level of helium

Post-doc

Hadi LOUTFI has joined the group on Oct. 2021. He actively contributes to the MARGIN project.

The MARGIN project (2020-2022)

MAgnetic Resonance studies of Gas diffusion In Nanoporous materials.
LKB (Coord. P.-J. Nacher) – MRS Lab, Kazan Fed. Univ. (Coord. M. Tagirov))

Project homepage  – Project overview
The Post-Doc position is now closed.

PhD student

Lionel DJADAOJEE (Teaching assistant at ENS Paris – PSL, Agrégé de Physique) has joined the group for PhD work on the metastable phases of solid and liquid 4He (J. Grücker, superviser; Sept. 2019 – …).

Winners

March 2019, PSL-iTeams closing session.

Read more

MULSA (an ecologically responsible alternative to conventional foam board) has been selected as best project at the end of the 2018/2019 PSL-iTeams training program (entrepreneurship education for PSL Master and PhD students, promoting interdiscplinarity and innovation). The project has been designed and defended on March 26 by Fiona Guillemant (ENSAD 2018), Baptiste Lefebvre ( PhD student, ENS), and Ali Dia.

In memoriam

Philippe Jacquier, leader of the “Quantum solid and liquid helium” team since 2003, passed away on Jan.24, 2019.

Read more

Philippe has battled against disease for many years with impressive courage and steadfast determination. He was an excellent teacher and a passionate researcher. The group will long miss his deep sense of humour and friendship, as well as the enthousiasm, the inventiveness, the curiosity, and the broad knowledge that made working with him so pleasant every day.

Short text (in French) by Antoine Heidmann, Director of the LKB.Ph. Jacquier’s scientific homepage

People

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Polarised He & quantum fluids
Quantum solid & liquid He
  • Franck Laloë
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  • Geneviève Tastevin
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  • Hadi LOUTFI
  • Zeyuan ZHANG
  • Jules Grucker
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  • Lionel Djadaojee

Recent Papers

A. Maul, P. Blümler, P.-J. Nacher, E. Otten, G. Tastevin, and W. Heil

Phys. Rev. A 98, 063405 (2018)

T. R. Gentile, P. J. Nacher, B. Saam, and T. G. Walker

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

L. Djadaojee, A. Douillet, and J. Grücker

Eur. Phys. J. Appl. Phys. 89, 30701 (2020)

Jules Grucker

J. Low. Temp. Phys. 197, 149–166 (2019)

G. Tastevin and F. Laloë

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

M.E. Hayden, and P.-J. Nacher

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

P.-J. Nacher, S. Kumaragamage, G. Tastevin, and C.P. Bidinosti

J. Magn. Reson. 310, 106638 (2020)

V. Kuzmin and P.-J. Nacher

J. Magn. Reson. 310, 106622 (2020)

JOB OFFERS

2022 - PhD position (ANR funding)

Hyperpolarisation of ³He nuclear spin at high magnetic field

 PhD position : Filled

Master 2 internship

Brillouin spectroscopy in superfluid 4He

Please have a look at this poster and contact us (grucker at lkb.ens.fr).

Master 2 / Opening for PhD

Hyperpolarisation of 3He at low/moderate magnetic field

M2 internship (2021/2022): Probing nuclear spin self-orientation in 3He gas discharges (Position is closed)

Please have a look at this poster (bottom part) - Visit our website - Contact us.

M2 internship (2021/2022) / Opening for PhD: Come and join the team for various investigations of polarisation dynamics in He gas discharges at low and moderate magnetic fields. Type of work: Experimental, numerical, theoretical.

Master 2 / Opening for PhD

 

Low field MRI - Polarised helium-3

Please have a look at this poster (top part).

M2 position : Open

Skilled and motivated students are welcome to join our investigations on low field MRI with laser-polarised ³He gas or thermally-polarised water samples. Work may focus on the impact of concomitant field gradients on image quality. Another objective may be to investigate the short-pulse limit and revisit the Bloch-Siegert effect in pulsed NMR. (This topic is open for PhD.). Please contact us for more information.

Master 2 internship

 

Polarised helium - Liquid NMR

Skilled and motivated students are welcome to join the team for follow-up of our investigations on liquid NMR in laser polarised ³He-⁴He dilute solutions. Work will deal with the latest observations of non linear NMR dynamics and will focus on the comparison between experimental and numerical data. This topic is not open for PhD this year.

We are always looking for brillant motivated scientists to join our group.

Check the open positions (see above) or send us your CV for application.

CONTACT

Département de Physique Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05  

  •  Jules Grucker  : jules.grucker at lkb.ens.fr
  • Franck Laloë : laloe at lkb.ens.fr
  • Pierre-Jean Nacher : nacher at lkb.ens.fr
  • Geneviève Tastevin : genevieve.tastevin at lkb.ens.fr

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