A5068894444- Cold Atom Physics and Bose-Einstein Condensates
- Quantum, superfluid, helium dynamics
- Quantum Information and Cryptography
- Atomic and Subatomic Physics Research
- Quantum optics and atomic interactions
- Diamond and Carbon-based Materials Research
- Advanced Thermodynamics and Statistical Mechanics
- Quantum Mechanics and Applications
- Advanced Frequency and Time Standards
- Advanced Fiber Laser Technologies
- Strong Light-Matter Interactions
- Spectroscopy and Laser Applications
- Quantum Computing Algorithms and Architecture
- Quantum many-body systems
- Spectroscopy and Quantum Chemical Studies
- High-pressure geophysics and materials
- Force Microscopy Techniques and Applications
- Mechanical and Optical Resonators
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Photonic and Optical Devices
- Nonlinear Optical Materials Studies
- Advanced MRI Techniques and Applications
- NMR spectroscopy and applications
- Electronic and Structural Properties of Oxides
University of Kaiserslautern
2016-2025
Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
2015-2024
University of Koblenz and Landau
2024
Fraunhofer Institute for Industrial Mathematics
2022
Daimler (Germany)
2015-2020
Schrodinger (United States)
2013
University of Bonn
2007-2011
Jeonbuk National University
2011
Quantum Design (Germany)
2005-2008
Institut für Technische und Angewandte Physik (Germany)
2008
The quantum walk is the analog of well-known random walk, which forms basis for models and applications in many realms science. Its properties are markedly different from classical counterpart might lead to extensive information In our experiment, we implemented a on line with single neutral atoms by deterministically delocalizing them over sites one-dimensional spin-dependent optical lattice. With use site-resolved fluorescence imaging, final wave function characterized local state...
We demonstrate the controlled coherent transport and splitting of atomic wave packets in spin-dependent optical lattice potentials. Such experiments open intriguing possibilities for quantum state engineering many body states. After first preparing localized functions an through a Mott insulating phase, we place each atom superposition two internal spin Then selective potentials are used to split function single corresponding opposite directions. Coherence between delocalized over up 7 sites...
Deviations from Brownian motion leading to anomalous diffusion are ubiquitously found in transport dynamics, playing a crucial role phenomena quantum physics life sciences. The detection and characterization of the measurement an individual trajectory challenging tasks, which traditionally rely on calculating mean squared displacement trajectory. However, this approach breaks down for cases important practical interest, e.g., short or noisy trajectories, ensembles heterogeneous non-ergodic...
We study experimentally interaction-driven spin oscillations in optical lattices the presence of an off-resonant microwave field. show that energy shift induced by this field can be used to control tuning system either into resonance achieve near-unity contrast or far away from suppress oscillations. Finally, we propose a scheme based on technique create flat sample with singly doubly occupied sites, starting inhomogeneous Mott insulator, where and sites coexist.
We report on the realization of a multiorbital system with ultracold atoms in excited bands 3D optical lattice by selectively controlling band population along given direction. The lifetime is found to be considerably longer (10-100 times) than characteristic time scale for intersite tunneling, thus opening path orbital selective many-body physics atoms. Upon exciting from an initial lowest Mott-insulating state higher lying bands, we observe dynamical emergence coherence 1D (and 2D),...
We report on the direct observation of transition from a compressible superfluid to an incompressible Mott insulator by recording in-trap density distribution Bosonic quantum gas in optical lattice. Using spatially selective microwave transitions and spin-changing collisions, we are able locally modify spin state trapped record spatial lattice sites with different filling factors. As system evolves insulator, observe formation distinct shell structure, good agreement theory.
We report on precision measurements of spin-dependent interaction-strengths in the 87Rb spin-1 and spin-2 hyperfine ground states. Our method is based recent observation coherence collisionally driven spin-dynamics ultracold atom pairs trapped optical lattices. Analysis Rabi-type oscillations between two spin states an pair allows a direct determination coupling parameters interaction Hamiltonian. deduce differences scattering lengths from our data that can directly be compared to...
We investigate the phase coherence properties of ultracold Bose gases in optical lattices, with special emphasis on Mott insulating phase. show that short length scales persists even deep phase, preserving a finite visibility interference pattern observed after free expansion. This behavior can be attributed to coherent admixture particle-hole pairs perfect state for small but tunneling. In addition, reproducible kinks are seen visibility, broad range atom numbers. interpret them as...
We report on controlled doping of an ultracold Rb gas with single neutral Cs impurity atoms. Elastic two-body collisions lead to a rapid thermalization the inside gas, representing first realization doped precisely known number atoms interacting via $s$-wave collisions. Inelastic interactions are restricted three-body recombination channel in highly and pure setting, which allows us determine Rb-Rb-Cs loss rate unprecedented precision. Our results pave way for coherently hybrid system...
Quantum probes are atomic sized devices mapping information of their environment to quantum-mechanical states. By improving measurements and at the same time minimizing perturbation environment, they form a central asset for quantum technologies. We realize spin-based by immersing individual Cs atoms into an ultracold Rb bath. Controlling inelastic spin-exchange processes between probe bath allows us map motional thermal onto quantum-spin show that steady-state spin population is well suited...
We report on the observation of coherent, purely collisionally driven spin dynamics neutral atoms in an optical lattice. For high lattice depths, atom pairs confined to same site show weakly damped Rabi-type oscillations between two-particle Zeeman states equal magnetization, induced by changing collisions. This paves way towards efficient creation robust entangled Moreover, measurement oscillation frequency allows for precise determination spin-changing collisional coupling strengths, which...
We analyze theoretically the experiment reported in [F. Gerbier et al., Phys. Rev. Lett. 95, 050404 (2005)]. There, interference pattern produced by an expanding atomic cloud Mott insulator regime was observed, indicative of short-range coherence system. The latter traced back to presence a small amount particle-hole pairs insulating phase for finite lattice depths. influence these on using random approximation, and derive corresponding visibility. also account inhomogeneity inherent atom...
We demonstrate quantum control over both internal and external degrees of freedom in a high number identical "chemical reactions," carried out an array microtraps 3D optical lattice. Starting from Mott insulating phase ultracold atomic gas, we use two-photon Raman transitions to create molecules on lattice sites occupied by two atoms. In the atom-molecule conversion process, can rovibronic center mass state molecules. The isolates microscopic chemical reactions each other, thereby allowing...
We report on a matter wave interferometer realized with entangled pairs of trapped 87Rb atoms. Each pair atoms is confined at single site an optical lattice potential. The by first creating coherent spin superposition the two and then tuning interstate scattering length via Feshbach resonance. selective change leads to entanglement dynamics two-particle state that can be detected in Ramsey interference experiment. This employed for precision measurement atomic interaction parameters....
We report on the observation of many-body spin dynamics interacting, one-dimensional (1D) ultracold bosonic gases with two states. By controlling nonlinear atomic interactions close to a Feshbach resonance we are able induce phase diffusive relative between components. monitor this dynamical evolution by Ramsey interferometry, supplemented novel, echo technique, which unveils role quantum fluctuations in 1D. find that time system is well described Luttinger liquid initially prepared...
We analyze the interference pattern produced by ultracold atoms released from an optical lattice, commonly interpreted as momentum distributions of trapped quantum gas. show that for finite times flight resulting density distribution can, however, be significantly altered, similar to a near-field diffraction regime in optics. illustrate our findings with simple model and realistic Monte Carlo simulations bosonic compare latter experiments.
We overcome the diffraction limit in fluorescence imaging of neutral atoms a sparsely filled one-dimensional optical lattice. At periodicity 433 nm, we reliably infer separation two down to nearest neighbors. observe light induced losses occupying same lattice site, while for adjacent sites, no due interactions occur. Our method points towards characterization correlated quantum states systems with filling factors up one atom per site.
We experimentally demonstrate the elementary case of electromagnetically induced transparency (EIT) with a single atom inside an optical cavity probed by weak field. observe modification dispersive and absorptive properties changing frequency control light Moreover, strong cooling effect has been observed at two-photon resonance, increasing storage time our atoms twenty-fold to about 16 seconds. Our result points towards all-optical switching photons.
We report on image processing techniques and experimental procedures to determine the lattice-site positions of single atoms in an optical lattice with high reliability, even for limited acquisition time or resolution. Determining beyond diffraction limit relies parametric deconvolution close analogy methods employed super-resolution microscopy. develop a method that makes effective use prior knowledge transfer function, noise properties, discreteness lattice. show accurate formation process...