A5079927290- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Spectroscopy and Laser Applications
- Atomic and Molecular Physics
- Quantum, superfluid, helium dynamics
- Mechanical and Optical Resonators
- Advanced Frequency and Time Standards
- Advanced Chemical Physics Studies
- Quantum optics and atomic interactions
- Laser-Matter Interactions and Applications
- Atmospheric Ozone and Climate
- Astrophysics and Star Formation Studies
- Quantum Information and Cryptography
- Particle accelerators and beam dynamics
- Particle Accelerators and Free-Electron Lasers
- Molecular Spectroscopy and Structure
- Various Chemistry Research Topics
- Laser Design and Applications
- Quantum Mechanics and Applications
- Spectroscopy and Quantum Chemical Studies
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Quantum Electrodynamics and Casimir Effect
- Astrophysics and Cosmic Phenomena
- Microfluidic and Capillary Electrophoresis Applications
Vrije Universiteit Amsterdam
2014-2024
University of Groningen
2019-2024
ETH Zurich
2023
National Institute for Subatomic Physics
2021
Tel Aviv University
2021
Fritz Haber Institute of the Max Planck Society
2003-2009
Institute for Atomic and Molecular Physics
2000-2006
Radboud University Nijmegen
1999-2004
It is experimentally demonstrated that a beam of neutral dipolar molecules can be efficiently decelerated with time-varying electric field. A pulsed metastable CO slowed down from 225 m/s ( ${E}_{\mathrm{kin}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}59{\mathrm{cm}}^{\ensuremath{-}1}$) to 98 ${E}_{\mathrm{kin}}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}11{\mathrm{cm}}^{\ensuremath{-}1}$) upon passage through an array 63 synchronously field stages.
Inspired by the spectacular successes in field of cold atoms, there is currently great interest molecules. Cooling molecules useful for various fundamental physics studies and gives access to an exotic regime chemistry where wave property becomes important. Although cooling has turned out be considerably more difficult than a number methods produce samples have been demonstrated over last few years. This paper aims review application them. Emphasis put on deceleration polar using...
A polar molecule experiences a force in an inhomogeneous electric field. Using this force, neutral molecules can be decelerated and trapped. It is shown here that principle done without loss phase-space density. series of 64 pulsed fields supersonic beam ammonia ${(}^{14}{\mathrm{NH}}_{3},$ ${}^{14}{\mathrm{ND}}_{3},$ ${}^{15}{\mathrm{ND}}_{3})$ decelerated. Subsequently, the are loaded into electrostatic quadrupole trap. Densities on order ${10}^{7}...
We have decelerated a supersonic beam of $^{174}\mathrm{YbF}$ molecules using switched sequence electrostatic field gradients. These are 7 times heavier than any previously decelerated. An alternating gradient structure allows us to decelerate and focus the in their ground state. show that decelerator exhibits axial transverse stability required bring rest. Our work significantly extends range amenable this powerful method cooling trapping.
The standard model of physics is built on the fundamental constants nature, but it does not provide an explanation for their values, nor require constancy over space and time. Here we set a limit possible cosmological variation proton-to-electron mass ratio μ by comparing transitions in methanol observed early universe with those measured laboratory. From radio-astronomical observations PKS1830-211, deduced constraint Δμ/μ = (0.0 ± 1.0) × 10(-7) at redshift z 0.89, corresponding to look-back...
We investigate the merits of a measurement permanent electric dipole moment electron ($e$EDM) with barium monofluoride molecules, thereby searching for phenomena CP violation beyond those incorporated in Standard Model particle physics. Although BaF molecule has smaller enhancement factor terms effective field than other molecules used current studies (YbF, ThO and ThF$^+$), we show that competitive is possible by combining Stark-deceleration, laser-cooling an intense primary cold source...
The NL-eEDM collaboration is building an experimental setup to search for the permanent electric dipole moment of electron in a slow beam cold barium fluoride molecules [Eur. Phys. J. D, 72, 197 (2018)]. Knowledge molecular properties BaF thus needed plan measurements and particular determine optimal laser-cooling scheme. Accurate reliable theoretical predictions these require incorporation both high-order correlation relativistic effects calculations. In this work investigations ground...
A series of pulsed electric fields can be arranged such that it creates a traveling potential well in which neutral dipolar molecules confined. This provides method to transport, decelerate, and cool sample while maintaining the initial phase-space density. is described using concept phase stability. The oscillating motion well, reaching minimum velocity spread corresponding translational temperature 4 mK, experimentally observed.
We here report on the realization of an electrodynamic trap, capable trapping neutral atoms and molecules in both low-field high-field seeking states. Confinement three dimensions is achieved by switching between two electric field configurations that have a saddle point at center i.e., alternating focusing defocusing force each direction. The ac 15ND(3) experimentally demonstrated, stability trap studied as function frequency. A 1 mK sample component |J,K=|1,1 level, ground state...
A limit on a possible cosmological variation of the proton-to-electron mass ratio μ is derived from methanol (CH3OH) absorption lines in benchmark PKS1830-211 lensing galaxy at redshift z=0.89 observed with Effelsberg 100-m radio telescope, Institute de Radio Astronomie Millimétrique 30-m and Atacama Large Millimeter/submillimeter Array. Ten different CH3OH covering wide range sensitivity coefficients K(μ) are used to derive purely statistical 1σ constraint Δμ/μ=(1.5±1.5)×10(-7) for lookback...
The 6.7 and 12.2 GHz masers, corresponding to the ${5}_{1}\ensuremath{\rightarrow}{6}_{0}{A}^{+}$ ${2}_{0}\ensuremath{\rightarrow}{3}_{\ensuremath{-}1}E$ transitions in methanol (${\mathrm{CH}}_{3}\mathrm{OH}$), respectively, are among brightest radio objects sky. We present calculations for sensitivity of these other ground state a variation proton-to-electron mass ratio. show that is greatly enhanced due cancellation energies associated with hindered internal rotation overall molecule....
Transitions in atoms and molecules provide an ideal test ground for constraining or detecting a possible variation of the fundamental constants nature. In this Perspective, we review molecular species that are specific interest search drifting proton-to-electron mass ratio $\mu$. particular, outline procedures used to calculate sensitivity coefficients transitions these discuss current searches. These methods have led rate change $\mu$ bounded $6 \times 10^{-14}$/yr from laboratory...
The ionization energy of ortho-H_{2} has been determined to be E_{I}^{o}(H_{2})/(hc)=124 357.238 062(25) cm^{-1} from measurements the GK(1,1)-X(0,1) interval by Doppler-free, two-photon spectroscopy using a narrow band 179-nm laser source and GK(1,1) state continuous-wave, near-infrared spectroscopy. E_{I}^{o}(H_{2}) was used derive dissociation H_{2}, D_{0}^{N=1}(H_{2}), at 35 999.582 894(25) with precision that is more than one order magnitude better all previous results. new result...
Neutral dipolar molecules can be decelerated and trapped using time-varying inhomogeneous electric fields. This has been demonstrated only for in low-field seeking states, but can, principle, performed on high-field states as well. Transverse stability is then much more difficult to obtain, however, since always experience a force towards the electrodes. Here we demonstrate that an array of dipole lenses alternate gradient configuration used maintain transverse stability. A pulsed beam...
The recent demonstration of cooling and manipulation techniques for molecules offer newpossibilities precision measurements in molecules. Here, we present the design a molecularfountain based on Stark decelerated molecular beam. In this fountain, ammonia aredecelerated to few meter per second, cooled sub microKelvin temperatures subsequentlylaunched. fly upwards some 30 cm before falling back under gravity, thereby passing amicrowave cavity twice – as they up fall down. effective...
We report Karl G. Jansky Very Large Array (VLA) absorption spectroscopy in four methanol (CH$_3$OH) lines the $z = 0.88582$ gravitational lens towards PKS1830-211. Three of have very different sensitivity coefficients $K_\mu$ to changes proton-electron mass ratio $\mu$; a comparison between line redshifts thus allows us test for temporal evolution $\mu$. obtain stringent statistical constraint on $\mu$ by comparing redshifted 12.179 GHz and 60.531 lines, $[\Delta mu/\mu] \leq 1.1 \times...
The resolution of any spectroscopic or interferometric experiment is ultimately limited by the total time a particle interrogated. We here demonstrate first molecular fountain, development which permits hitherto unattainably long interrogation times with molecules. In our experiments, ammonia molecules are decelerated and cooled using electric fields, launched upwards velocity between 1.4 1.9\,m/s observed as they fall back under gravity. A combination quadrupole lenses bunching elements...
Beams of polar molecules can be focused using an array electrostatic lenses in alternating gradient (AG) configuration. They also accelerated or decelerated by applying appropriate high voltage switching sequence to the lenses. AG focusing is applicable both low-field and high-field-seeking states particularly well suited problem decelerating heavy those their ground rotational state. We describe principles deceleration set out criteria followed decelerator design, construction operation....
A microstructured array of over 1200 electrodes on a substrate has been configured to generate an local minima electric field strength with periodicity 120 microm about 25 above the substrate. By applying sinusoidally varying potentials electrodes, these can be made move smoothly along array. Polar molecules in low seeking quantum states trapped traveling potential wells. This is experimentally demonstrated by transporting metastable CO 30 mK deep wells that at constant velocities