A5073151564- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Frequency and Time Standards
- Atomic and Subatomic Physics Research
- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Ocular and Laser Science Research
- Quantum, superfluid, helium dynamics
- Atomic and Molecular Physics
- Intraocular Surgery and Lenses
- Scientific Measurement and Uncertainty Evaluation
- Laser Material Processing Techniques
- Solid State Laser Technologies
- Quantum optics and atomic interactions
- Advanced Fiber Laser Technologies
- Corneal surgery and disorders
- Spectroscopy and Laser Applications
- Laser Design and Applications
- Strong Light-Matter Interactions
- Photoacoustic and Ultrasonic Imaging
- Mechanical and Optical Resonators
- Laser-Matter Interactions and Applications
- Radioactive Decay and Measurement Techniques
- Laser Applications in Dentistry and Medicine
- Advanced Chemical Physics Studies
- Geophysics and Sensor Technology
Leibniz University Hannover
2014-2024
Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
2020-2023
Laser Zentrum Hannover
2002-2018
Systèmes de Référence Temps-Espace
2018
University of Bologna
2011
University of Bonn
1989-2008
Institut für Qualität im Management (Germany)
2008
Institut für Technische und Angewandte Physik (Germany)
1987-1995
Poznań University of Technology
1994
Royal Holloway University of London
1994
Dark solitons in cigar shaped Bose-Einstein condensates of Rubidium-87 are created by a phase imprinting method. Coherent and dissipative dynamics the has been observed.
Interferometers with atomic ensembles constitute an integral part of modern precision metrology. However, these interferometers are fundamentally restricted by the shot noise limit, which can only be overcome creating quantum entanglement among atoms. We used spin dynamics in Bose-Einstein condensates to create large up $10^4$ pair-correlated atoms interferometric sensitivity $-1.61^{+0.98}_{-1.1}$ dB beyond limit. Our proof-of-principle results point way toward a new generation atom interferometers.
Atom interferometers covering macroscopic domains of space-time are a spectacular manifestation the wave nature matter. Because their unique coherence properties, Bose-Einstein condensates ideal sources for an atom interferometer in extended free fall. In this Letter we report on realization asymmetric Mach-Zehnder operated with condensate microgravity. The resulting interference pattern is similar to one far field double slit and shows linear scaling time packets expand. We employ...
Atomic-beam sodium atoms were slowed to zero or negative velocities by counterpropagating laser radiation which was frequency chirped with precise electro-optic modulation techniques. The resulting "gas cloud" had a temperature below 50 mK and density above ${10}^{6}$ atoms/${\mathrm{cm}}^{3}$. We mention future possibilities in atom slowing, deflection, storage.
We simultaneously measure the gravitationally induced phase shift in two Raman-type matter-wave interferometers operated with laser-cooled ensembles of Rb87 and K39 atoms. Our measurement yields an Eötvös ratio ηRb,K=(0.3±5.4)×10−7. briefly estimate possible bias effects present strategies for future improvements.Received 1 April 2014DOI:https://doi.org/10.1103/PhysRevLett.112.203002© 2014 American Physical Society
Albert Einstein's insight that it is impossible to distinguish a local experiment in "freely falling elevator" from one free space led the development of theory general relativity. The wave nature matter manifests itself striking way Bose-Einstein condensates, where millions atoms lose their identity and can be described by single macroscopic function. We combine these two topics report preparation observation condensate during fall 146-meter-tall evacuated drop tower. During expansion over...
The theory of general relativity describes macroscopic phenomena driven by the influence gravity while quantum mechanics brilliantly accounts for microscopic effects.Despite their tremendous individual success, a complete unification fundamental interactions is missing and remains one most challenging important quests in modern theoretical physics.The STE-QUEST satellite mission, proposed as medium-size mission within Cosmic Vision program European Space Agency (ESA), aims testing with high...
The occurrence of phase fluctuations due to thermal excitations in Bose-Einstein condensates (BECs) is studied for a variety temperatures and trap geometries. We observe the statistical nature appearance characterize dependence their average value on temperature, number particles, trapping potential. find pronounced very elongated traps broad temperature range. results are great importance realization BEC quasi-1D geometries, matter wave interferometry with BECs, as well coherence properties...
We investigate, both experimentally and theoretically, possible routes towards Anderson-like localization of Bose-Einstein condensates in disordered potentials. The dependence this quantum interference effect on the nonlinear interactions shape disorder potential is investigated. Experiments with an optical lattice a superimposed reveal lack Anderson localization. A theoretical analysis shows that absence due to large length scale as well its screening by interactions. Further...
We realize beam splitters and mirrors for atom waves by employing a sequence of light pulses rather than individual ones. In this way we can tailor interferometers with improved sensitivity accuracy. demonstrate our method composite creating symmetric matter-wave interferometer which combines the advantages conventional Bragg- Raman-type concepts. This feature leads to an high immunity technical noise allowing us devise large-area Sagnac gyroscope yielding phase shift 6.5 rad due Earth's...
We demonstrate a quantum gravimeter by combining the advantages of an atom chip for generation, delta-kick collimation, and coherent manipulation freely falling Bose-Einstein condensates (BECs) with innovative launch mechanism based on Bloch oscillations double Bragg diffraction. Our high-contrast BEC interferometer realizes tens milliseconds free fall in volume as little one centimeter cube paves way measurements sub-μGal accuracies miniaturized, robust devices.Received 13 May...
Do the laws of quantum physics still hold for macroscopic objects - this is at heart Schrödinger's cat paradox or do gravitation yet unknown effects set a limit massive particles? What fundamental relation between and gravity? Ground-based experiments addressing these questions may soon face limitations due to limited free-fall times quality vacuum microgravity. The proposed mission Macroscopic Quantum Resonators (MAQRO) overcome allow such questions. MAQRO harnesses recent developments in...
Abstract In 1935, Einstein, Podolsky and Rosen (EPR) questioned the completeness of quantum mechanics by devising a state two massive particles with maximally correlated space momentum coordinates. The EPR criterion qualifies such continuous-variable entangled states, where measurement one subsystem seemingly allows for prediction second beyond Heisenberg uncertainty relation. Up to now, correlations have only been created photons, while demonstration strongly states is still outstanding....
We propose a terrestrial detector for gravitational waves with frequencies between 0.3 and 5 Hz based on atom interferometry. As key elements, we discuss two symmetric matter-wave interferometers, the first one single loop second featuring folded triple-loop geometry. The latter eliminates need atomic ensembles at femtokelvin energies imposed by Sagnac effect in other interferometric detectors. geometry also combines several advantages of current vertical horizontal matter wave antennas...
We report on the creation of Bose-Einstein condensates $^{87}$Rb in a specially designed hybrid, dipole and magnetic trap. This trap naturally allows coherent transfer matter waves into pure potential waveguide based doughnut beam. Specifically, we present studies coherence ensemble hybrid during evolution by means an autocorrelation interferometer scheme. By monitoring expansion observe mean field dominated acceleration much longer time scale than free 3D expansion. Both interference...
We investigate the evolution of Bose-Einstein condensates falling under gravity and bouncing off a mirror formed by far-detuned sheet light. After reflection, atomic density profile develops splitting interference structures which depend on drop height, strength light sheet, as well initial mean field energy size condensate. compare experimental results with simulations Gross-Pitaevski equation. A comparison behavior thermal clouds allows us to identify quantum features specific for...
Ultracold atoms at temperatures close to the recoil limit have been achieved by extending Doppler cooling forbidden transitions. A cloud of ^40Ca has cooled and trapped a temperature as low 6 \mu K operating magneto-optical trap on spin-forbidden intercombination transition. Quenching long-lived excited state with an additional laser enhanced scattering rate factor 15, while high selectivity in velocity was preserved. With this method more than 10% pre-cooled from standard transferred...
We measure the intensity correlation function of two interfering spatially displaced copies a phase fluctuating Bose-Einstein Condensate (BEC). It is shown that this corresponds to measurement properties initial condensate. Analogous method used in stellar interferometer experiment Hanbury Brown and Twiss, we use spatial correlations determine coherence lengths elongated BECs. find good agreement with our prediction confirm expected length.
Three-level atom optics is introduced as a simple, efficient, and robust method to coherently manipulate transport neutral atoms. The tunneling interaction among three trapped states allows us realize the spatial analog of stimulated Raman adiabatic passage, coherent population trapping, electromagnetically induced transparency techniques offers wide range possible applications. We investigate an implementation in optical microtrap arrays show that under realistic parameters manipulation...