Dr. Jeroen Koelemeij

Assistant professor

One PhD and one Postdoc position available on our HD+ experiment - link to appear soon

Recent news (last updated Sep 25, 2020) :

  • September 2020: After years of arduous work, we finally completed our HD+ two-photon spectroscopy campaign, and combined it with the latest molecular theory from our coworkers at LKB Paris and JINR Dubna - and with what a result! A new measurement of the proton-electron mass ratio, more precise than what was obtained by the best other methods so far, and a confirmation that the proton mass and radius are indeed smaller than previously thought.
    See our paper in Science (pdf), and also the nice Perspective by Masaki Hori. More media coverage here.

  • September 2020: Check out this great paper in Nature by a German collaboration about a new and very precise determination of the deuteron mass, and its consequences for what has been called the 'nuclear mass puzzle'.
    See also my News & Views commentary in Nature.

  • What happened between 2017 and 2020: from 2017 to 2019 I worked full-time at OPNT BV, our university spin-off company, to help the company grow to twelve employees. Lots of fun and progress in fiber-optic time and frequency transfer, and lots of recognition for the company's work (see for example this invited presentation for the US GPS Advisory Board) - but when the opportunity arose to return to academic science and my beloved fundamental research at LaserLaB VU... I could not resist!

  • March 2016: SuperGPS project started! The SuperGPS project is a collaboration of our group at VU University with colleagues at the Faculty of Civil Engineering and Geosciences and the Faculty of Electrical Engineering, Mathematics and Computer Science at Delft University of Technology. The project is funded through technology foundation STW with support from stakeholders including KPN, OPNT, VSL, TNO, and Fugro Geoservices.

  • February 2016: Four new papers out!

    "Probing QED and fundamental constants through laser spectroscopy of vibrational transitions in HD+,"
    J. Biesheuvel, J.-Ph. Karr, L. Hilico, K.S.E. Eikema, W. Ubachs, J.C.J. Koelemeij, Nat. Commun. 7, 10385 (2016)
    see also the press release by FOM and the Volkskrant news article
    "Theoretical hyperfine structure of the molecular hydrogen ion at the 1 ppm level,"
    V.I. Korobov, J.C.J. Koelemeij, L. Hilico, J.-Ph. Karr, Phys. Rev. Lett. 116, 053003 (2016)

    "Physics beyond the Standard Model from hydrogen spectroscopy,"
    W. Ubachs, J.C.J. Koelemeij, K.S.E. Eikema, E.J. Salumbides, J. Mol. Spectr. 320, 1-12 (2016)

  • "White Rabbit Precision Time Protocol on Long Distance Fiber Links,"
    E.F. Dierikx, A.E. Wallin, T. Fordell, J. Myyry, P. Koponen, M. Merimaa, T.J. Pinkert, J.C.J. Koelemeij, H. Peek, R. Smets, IEEE Trans. Ultrason. Ferroelectr. Freq. Control., E-publication ahead of print (2016)

  • February 2016: Cottonwood Euro Technoloy Fund invests 500 kE in our spin-off company OPNT BV

  • November 2015: Travel grant extension awarded to the molecular hydrogen spectroscopy teams at VU Amsterdam and LKB Paris by the EP Nuffic Van Gogh Programme.

  • May 2015: our team participates in ME 15 EU H2020 project 'ASTERICS'

  • Older news

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  • Quantum Metrology and Laser Applications group
  • LaserLaB VU University
  • Laserlab Europe

Section Atomic, Molecular and Laser Physics - Vrije Universiteit Amsterdam
Address: De Boelelaan 1081, 1081 HV Amsterdam, The Netherlands
Telephone:+31(0)205987892 Fax:+31(0)205987992