Zobrazeno 1 - 10
of 117
pro vyhledávání: '"Wim Vassen"'
Autor:
R. F. H. J. van der Beek, Kjeld S. E. Eikema, Wim Vassen, Hendrick L. Bethlem, O. Onishchenko
Publikováno v:
Physical Review A, 102(6):061302, 1-6. American Physical Society
Physical Review A, 102(6):061302. AMER PHYSICAL SOC
Van Der Beek, R F H J, Onishchenko, O, Vassen, W, Eikema, K S E & Bethlem, H L 2020, ' Bloch oscillations with a metastable helium Bose-Einstein condensate ', Physical Review A, vol. 102, no. 6, 061302, pp. 1-6 . https://doi.org/10.1103/PhysRevA.102.061302
Physical Review A, 102(6):061302. AMER PHYSICAL SOC
Van Der Beek, R F H J, Onishchenko, O, Vassen, W, Eikema, K S E & Bethlem, H L 2020, ' Bloch oscillations with a metastable helium Bose-Einstein condensate ', Physical Review A, vol. 102, no. 6, 061302, pp. 1-6 . https://doi.org/10.1103/PhysRevA.102.061302
We have observed Bloch oscillations of a ${}^{4}{\text{He}}^{*}$ Bose-Einstein condensate in an optical lattice at 1557.3 nm. Due to its low mass, metastable helium was efficiently accelerated orders of magnitude faster than demonstrated with other a
Autor:
Wim Vassen, R. Jannin, R. J. Rengelink, Y.D. van der Werf, R. P. M. J. W. Notermans, Kjeld S. E. Eikema, Maarten Hoogerland
Publikováno v:
Rengelink, R J, van der Werf, Y, Notermans, R P M J W, Jannin, R, Eikema, K S E, Hoogerland, M D & Vassen, W 2018, ' Precision spectroscopy of helium in a magic wavelength optical dipole trap ', Nature Physics, vol. 14, no. 11, pp. 1132-1137 . https://doi.org/10.1038/s41567-018-0242-5
Nature Physics, 14(11), 1132-1137. Nature Publishing Group
Nature Physics, 14(11), 1132-1137. Nature Publishing Group
Improvements in both theory and frequency metrology of few-electron systems such as hydrogen and helium have enabled increasingly sensitive tests of quantum electrodynamics, as well as ever more accurate determinations of fundamental constants and th
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6ca0c707913613643a3681ea763c4d3c
https://research.vu.nl/en/publications/c1703190-ad45-427c-92ce-588cbc0817d3
https://research.vu.nl/en/publications/c1703190-ad45-427c-92ce-588cbc0817d3
Publikováno v:
Applied Physics B. Lasers and Optics, 121, 391-399. Springer Verlag
Flores, A S, Mishra, H P, Vassen, W & Knoop, S 2015, ' Simple method for producing Bose-Einstein condensates of metastable helium using a single beam optical dipole trap ', Applied Physics B. Lasers and Optics, vol. 121, pp. 391-399 . https://doi.org/10.1007/s00340-015-6243-5
Flores, A S, Mishra, H P, Vassen, W & Knoop, S 2015, ' Simple method for producing Bose-Einstein condensates of metastable helium using a single beam optical dipole trap ', Applied Physics B. Lasers and Optics, vol. 121, pp. 391-399 . https://doi.org/10.1007/s00340-015-6243-5
We demonstrate a simple scheme to reach Bose-Einstein condensation (BEC) of metastable triplet helium atoms using a single beam optical dipole trap with moderate power of less than 3 W. Our scheme is based on RF-induced evaporative cooling in a quadr
Autor:
Wim Vassen
Publikováno v:
Vassen, W 2017, ' The proton radius revisited ', Science, vol. 358, no. 6359, pp. 39-40 . https://doi.org/10.1126/science.aao3969
Science, 358(6359), 39-40. American Association for the Advancement of Science
Science, 358(6359), 39-40. American Association for the Advancement of Science
The nucleus of all atoms consists of protons and neutrons, and the simplest of all atoms, hydrogen, has just one proton. The radius of the proton is very small, about 1 fm (1 fm is 10−15 m), smaller than the radius of a hydrogen atom by a factor of
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::6ae988c0f69228dc734d945b23324dc4
https://hdl.handle.net/1871.1/086b7278-871d-4120-b9d2-edd2acd5e675
https://hdl.handle.net/1871.1/086b7278-871d-4120-b9d2-edd2acd5e675
Publikováno v:
Physical Review Letters. 118
Publikováno v:
Applied Physics B. Lasers and Optics, 2016(122):289. Springer Verlag
Vassen, W, Notermans, R P M J W, Rengelink, R J & van der Beek, R F H J 2016, ' Ultracold metastable helium: Ramsey fringes and atom interferometry ', Applied Physics B. Lasers and Optics, vol. 2016, no. 122, 289 . https://doi.org/10.1007/s00340-016-6563-0
Vassen, W, Notermans, R P M J W, Rengelink, R J & van der Beek, R F H J 2016, ' Ultracold metastable helium: Ramsey fringes and atom interferometry ', Applied Physics B. Lasers and Optics, vol. 2016, no. 122, 289 . https://doi.org/10.1007/s00340-016-6563-0
We report on interference studies in the internal and external degrees of freedom of metastable triplet helium atoms trapped near quantum degeneracy in a \( 1.5\kern0.166667em \upmu \mathrm{m} \) optical dipole trap. Applying a single \( \pi /2 \) rf
Publikováno v:
Physical Review Letters, 2016(117):213001. American Physical Society
Notermans, R P M J W, Rengelink, R J & Vassen, W 2016, ' Comparison of spectral linewidths for quantum degenerate bosons and fermions ', Physical Review Letters, vol. 2016, no. 117, 213001 . https://doi.org/10.1103/PhysRevLett.117.213001
Notermans, R P M J W, Rengelink, R J & Vassen, W 2016, ' Comparison of spectral linewidths for quantum degenerate bosons and fermions ', Physical Review Letters, vol. 2016, no. 117, 213001 . https://doi.org/10.1103/PhysRevLett.117.213001
We observe a dramatic difference in optical line shapes of a $^4\text{He}$ Bose-Einstein condensate and a $^3\text{He}$ degenerate Fermi gas by measuring the 1557-nm $2~^3S-2~^1S$ magnetic dipole transition ($8~\text{Hz}$ natural linewidth) in an opt
Publikováno v:
Physical Review A, 94(5):050701(R). American Physical Society
Flores, A S, Vassen, W & Knoop, S 2016, ' Quantum-state-controlled Penning-ionization reactions between ultracold alkali-metal and metastable helium atoms ', Physical Review A, vol. 94, no. 5, 050701(R) . https://doi.org/10.1103/PhysRevA.94.050701
Flores, A S, Vassen, W & Knoop, S 2016, ' Quantum-state-controlled Penning-ionization reactions between ultracold alkali-metal and metastable helium atoms ', Physical Review A, vol. 94, no. 5, 050701(R) . https://doi.org/10.1103/PhysRevA.94.050701
In an ultracold, optically trapped mixture of $^{87}$Rb and metastable triplet $^4$He atoms we have studied trap loss for different spin-state combinations, for which interspecies Penning ionization is the main two-body loss process. We observe long
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b6ec6acc38a45f000f604cf84891923b
Publikováno v:
Rengelink, R J, Notermans, R P M J W & Vassen, W 2016, ' A simple 2 W continuous-wave laser system for trapping ultracold metastable helium atoms at the 319.8 nm magic wavelength ', Applied Physics B. Lasers and Optics, vol. 2016, no. 122, 122 . https://doi.org/10.1007/s00340-016-6395-y
Applied Physics B. Lasers and Optics, 2016(122):122. Springer Verlag
Applied Physics B. Lasers and Optics, 2016(122):122. Springer Verlag
High precision spectroscopy on the $2 \ ^3 S \rightarrow 2 \ ^1 S$ transition is possible in ultracold optically trapped helium but the accuracy is limited by the ac-Stark shift induced by the optical dipole trap. To overcome this problem, we have bu
Autor:
Alain Aspect, Christoph I Westbrook, Wim Hogervorst, Hong Chang, Valentina Krachmalnicoff, J. M. McNamara, Aurélien Perrin, M. Schellekens, Wim Vassen, Denis Boiron, T. Jeltes
Publikováno v:
Nature, 445(7126), 402-405. Nature Publishing Group
Jeltes, T, McNamara, J M, Hogervorst, W, Vassen, W, Krachmalnicoff, V, Schellekens, M, Perrin, A, Chang, H, Boiron, D, Aspect, A & Westbrook, C I 2007, ' Comparison of the Hanbury Brown-Twiss effect for bosons and fermions ', Nature, vol. 445, no. 7126, pp. 402-405 . https://doi.org/10.1038/nature05513
Nature
Nature, Nature Publishing Group, 2007, 445, pp.402. ⟨10.1038/nature05513⟩
Jeltes, T, McNamara, J M, Hogervorst, W, Vassen, W, Krachmalnicoff, V, Schellekens, M, Perrin, A, Chang, H, Boiron, D, Aspect, A & Westbrook, C I 2007, ' Comparison of the Hanbury Brown-Twiss effect for bosons and fermions ', Nature, vol. 445, no. 7126, pp. 402-405 . https://doi.org/10.1038/nature05513
Nature
Nature, Nature Publishing Group, 2007, 445, pp.402. ⟨10.1038/nature05513⟩
Fifty years ago, Hanbury Brown and Twiss (HBT) discovered photon bunching in light emitted by a chaotic source, highlighting the importance of two-photon correlations and stimulating the development of modern quantum optics . The quantum interpretati