A5064563887- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Molecular Physics
- Quantum optics and atomic interactions
- Quantum Information and Cryptography
- Advanced Frequency and Time Standards
- Mass Spectrometry Techniques and Applications
- Atomic and Subatomic Physics Research
- Advanced Fiber Laser Technologies
- Mechanical and Optical Resonators
- Spectroscopy and Quantum Chemical Studies
- Spectroscopy and Laser Applications
- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Laser-Matter Interactions and Applications
- Ion-surface interactions and analysis
- Quantum Mechanics and Applications
- Force Microscopy Techniques and Applications
- Orbital Angular Momentum in Optics
- Analytical chemistry methods development
- Particle accelerators and beam dynamics
- Photonic and Optical Devices
- Advanced Materials Characterization Techniques
- Molecular spectroscopy and chirality
- Magnetic confinement fusion research
- Advanced Fiber Optic Sensors
Aarhus University
2013-2024
Danish National Research Foundation
2005-2014
Massachusetts Institute of Technology
2009
National Research Foundation
2003-2009
Argonne National Laboratory
2000
University of Chicago
2000
University of Konstanz
1996-1997
We have produced and cooled the molecular ions ${\mathrm{MgH}}^{+}$ ${\mathrm{MgD}}^{+}$ in a linear Paul trap. These were generated by photochemical reactions ${\mathrm{Mg}}^{+}{(3p}^{2}{P}_{3/2})+{\mathrm{H}}_{2} ({\mathrm{D}}_{2})\ensuremath{\rightarrow}{\mathrm{MgH}}^{+} ({\mathrm{MgD}}^{+})+\mathrm{H} (\mathrm{D}),$ identified radial separation trap of with different charge-to-mass ratios. The translational motion was sympathetically Coulomb interaction laser-cooled ${\mathrm{Mg}}^{+}$...
Plasmas of ${\mathrm{Mg}}^{+}$ ions, containing more than ${10}^{5}$ have been observed to reach well-ordered (crystalline) states by applying laser cooling. The crystals are highly elongated with up ten concentric cylindrical shells surrounding a central string. Such large structures not previously in Paul trap. amplitude the micromotion ions can be larger shell spacings. As diameter changes along crystals, sharp transitions when new form, good agreement molecular dynamics simulations....
STIRAP (Stimulated Raman Adiabatic Passage) is a powerful laser-based method, usually involving two photons, for efficient and selective transfer of population between quantum states. A particularly interesting feature the fact that coupling initial final states via an intermediate state even though lifetime latter can be much shorter than interaction time with laser radiation. Nevertheless, spontaneous emission from prevented by interference. Maintaining coherence throughout process...
Control over the motional degrees of freedom atoms, ions, and molecules in a field-free environment enables unrivalled measurement accuracies but has yet to be applied highly charged ions (HCIs), which are particular interest future atomic clock designs searches for physics beyond Standard Model. Here, we report on Coulomb crystallization HCIs (specifically (40)Ar(13+)) produced an electron beam ion trap retrapped cryogenic linear radiofrequency by means sympathetic cooling through...
A highly efficient method for optical or microwave detection and separation of left- right-handed chiral molecules is proposed. The utilizes a closed-loop three-state system in which the population dynamics depends on phases three couplings. Because different signs coupling between two states opposite chiralities chirality dependent. By using ``shortcuts to adiabaticity'' concept applied stimulated Raman adiabatic passage technique, one can achieve 100% contrast enantiomers particular state....
We report on structural properties of two-component Coulomb crystals in a linear Paul trap. The consist two laser cooled ion species, 24Mg+ and 40Ca+. lighter ions form an inner cylindrical crystal structure surprisingly similar to that infinitely long single component crystal, while the outermost shell surrounding 40Ca+ have spheroidal shape, which is highly insensitive presence ions. Observed changes radial separation species with radius explained by simple model.
We demonstrate a simple and nondestructive method for identification of single molecular ion sympathetically cooled by laser atomic in linear Paul trap. The technique is based on precise determination the mass through measurement eigenfrequency common motional mode two ions. demonstrated resolution sufficiently high that doublets can potentially be distinguished from each other. obtained results represent an important step towards molecule gas phase chemical physics.
We investigate a hybrid optomechanical system composed of micromechanical oscillator as movable membrane and an atomic three-level ensemble within optical cavity. show that suitably tailored cavity field response via electromagnetically induced transparency (EIT) in the medium allows for strong coupling membrane's mechanical oscillations to collective ground-state spin. This facilitates cooling motion, quantum state mapping, robust atom-membrane entanglement even widths larger than resonance...
Isotope effects in reactions between ${\mathrm{Mg}}^{+}$ the $3p$ $^{2}P_{3/2}$ excited state and molecular hydrogen at thermal energies are studied through single reaction events. From only $\ensuremath{\sim}250$ with HD, branching ratio formation of ${\mathrm{MgD}}^{+}$ ${\mathrm{MgH}}^{+}$ is found to be larger than 5. an additional 65 ${\mathrm{H}}_{2}$ ${\mathrm{D}}_{2}$ we find that overall fragmentation probability intermediate ${\mathrm{MgH}}_{2}^{+}$, ${\mathrm{MgHD}}^{+}$, or...
We perform high-resolution spectroscopy of the 3d D23/2−3d D25/2 interval in all stable even isotopes CaA+ (A=40, 42, 44, 46, and 48) with an accuracy ∼20 Hz using direct frequency-comb Raman spectroscopy. Combining these data isotope shift measurements 4s S21/2↔3d transition, we carry out a King plot analysis unprecedented sensitivity to coupling between electrons neutrons by bosons beyond standard model. Furthermore, estimate such from equivalent Ba+ Yb+. Finally, yield shifts D23/2...
We examine the time-dependent dynamics of ion crystals in radiofrequency traps. The problem stable trapping general three-dimensional is considered and validity pseudopotential approximation discussed. derive analytically micromotion amplitude ions, rigorously proving well-known experimental observations. use a method infinite determinants to find modes which diagonalize linearized dynamical problem. This allows obtaining explicitly ('Floquet-Lyapunov') transformation coordinates decoupled...
Storage and cooling of highly charged ions require ultra-high vacuum levels obtainable by means cryogenic methods. We have developed a linear Paul trap operating at 4 K capable very long ion storage times about 30 h. A conservative upper bound the H(2) partial pressure 10(-15) mbar (at K) is obtained from this. External injection possible optimized optical access for lasers provided, while exposure to black body radiation minimized. First results its operation with atomic molecular are...
Three-dimensional long-range ordered structures in smaller and near-spherically symmetric Coulomb crystals of (40)Ca(+) ions confined a linear rf Paul trap have been observed when the number exceeds approximately 1,000 ions. This result is unexpected from ground state molecular dynamics (MD) simulations, but found to be agreement with MD simulations metastable ion configurations. Previously, three-dimensional only reported Penning traps systems 50,000 or more.
We present two methods for efficient detection of chiral molecules based on sequences single pulses and Raman pulse pairs. The are modelled by a closed-loop three-state system with different signs in one the couplings enantiomers. One method uses sequence three interaction steps: pulse, another pulse. other only second is simpler faster but requires more sophisticated than first one. Both techniques allow straightforward generalizations replacing composite sequences. latter achieve very high...
We explore the interaction between two trapped ions mediated by a surrounding quantum degenerate Bose or Fermi gas. Using perturbation theory valid for weak atom-ion interaction, we show analytically that gas has power-law behavior large distances whereas it Yukawa form intermediate distances. For gas, is given power law density and Ruderman-Kittel-Kasuya-Yosida low density. strong use diagrammatic to demonstrate can be significant addition bare Coulomb ions, when an bound state close...