A5001546561- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Subatomic Physics Research
- Advanced Frequency and Time Standards
- Quantum Information and Cryptography
- Quantum, superfluid, helium dynamics
- Laser-Matter Interactions and Applications
- Strong Light-Matter Interactions
- Advanced Fiber Laser Technologies
- Nuclear physics research studies
- Atomic and Molecular Physics
- Quantum optics and atomic interactions
- Nuclear Physics and Applications
- Inorganic Fluorides and Related Compounds
- Scientific Measurement and Uncertainty Evaluation
- Radiation Detection and Scintillator Technologies
- Mass Spectrometry Techniques and Applications
- Advanced NMR Techniques and Applications
- Spectroscopy and Laser Applications
- Quantum Mechanics and Applications
- Radioactive Decay and Measurement Techniques
- Quantum many-body systems
- Spectroscopy and Quantum Chemical Studies
- Advanced Thermodynamics and Statistical Mechanics
- Quantum and electron transport phenomena
- Advanced Semiconductor Detectors and Materials
TU Wien
2016-2025
Vienna Center for Quantum Science and Technology
2013-2025
Physikalisch-Technische Bundesanstalt
2024
Osaka University
2023
Wolfgang Pauli Institute
2009-2014
University of Vienna
2009-2014
Heidelberg University
2003-2009
University of Toronto
2006-2008
Laboratoire Charles Fabry
2004-2006
Centre National de la Recherche Scientifique
2005-2006
Particle-wave duality enables the construction of interferometers for matter waves, which complement optical in precision measurement devices. This requires development atom-optics analogues to beam splitters, phase shifters and recombiners. Integrating these elements into a single device has been long-standing goal. Here we demonstrate full Mach–Zehnder sequence with trapped Bose–Einstein condensates confined on an atom chip. Particle interactions our condensate waves lead nonlinearity,...
Abstract The low-energy, long-lived isomer in 229 Th, first studied the 1970s as an exotic feature nuclear physics, continues to inspire a multidisciplinary community of physicists. It has stimulated innovative ideas and studies that expand understanding atomic structure heavy elements interaction nuclei with bound electrons coherent light. Using resonance frequency, determined by strong electromagnetic interactions inside nucleus, it is possible build highly precise clock will be...
The 8.4 eV nuclear isomer state in Th-229 is resonantly excited Th-doped <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>CaF</a:mi></a:mrow><a:mrow><a:mn>2</a:mn></a:mrow></a:msub></a:mrow></a:math> crystals using a tabletop tunable laser system. A resonance fluorescence signal observed two with different dopant concentrations, while it absent control experiment Th-232. for the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"...
We report in situ measurements of density fluctuations a quasi-one-dimensional $^{87}\mathrm{Rb}$ Bose gas at thermal equilibrium an elongated harmonic trap. observe excess compared to the shot-noise level expected for uncorrelated atoms. At low atomic density, measured is good agreement with ``bunching'' ideal gas. high are strongly reduced case. attribute this reduction repulsive interatomic interactions. The data calculation interacting quasicondensate regime.
We present an experimental study on the nonequilibrium tunnel dynamics of two coupled one-dimensional Bose-Einstein quasicondensates deep in Josephson regime. oscillations are initiated by splitting a single condensate and imprinting relative phase between superfluids. Regardless initial state parameters, atom number imbalance shows relaxation to phase-locked steady state. The latter is characterized high coherence reduced fluctuations with respect propose empirical model based analogy...
We present a measurement of the low-energy (0–60 keV) γ-ray spectrum produced in α decay U233 using dedicated cryogenic magnetic microcalorimeter. The energy resolution ∼10 eV, together with exceptional gain linearity, allows us to determine low-lying isomeric state Th229 four complementary evaluation schemes. most precise scheme determines isomer be 8.10(17) corresponding 153.1(32) nm, superseding precision previous values based on γ spectroscopy, and agreeing recent internal conversion...
Abstract We have grown $$^{232}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow/> <mml:mn>232</mml:mn> </mml:msup> </mml:math> Th:CaF $$_2$$ <mml:msub> <mml:mn>2</mml:mn> </mml:msub> and $$^{229}$$ <mml:mn>229</mml:mn> single crystals for investigations on the VUV laser-accessible first nuclear excited state of Th, with aim building a solid-state clock. To reach high doping concentrations despite extreme scarcity (and radioactivity) we scaled down crystal...
A comparative vacuum ultraviolet spectroscopy study conducted at ISOLDE-CERN of the radiative decay <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mmultiscripts><a:mi>Th</a:mi><a:mprescripts/><a:none/><a:mrow><a:mn>229</a:mn><a:mi>m</a:mi></a:mrow></a:mmultiscripts></a:math> nuclear clock isomer embedded in different host materials is reported. The ratio number photons and <b:math...
Adiabatic dressed state potentials are created when magnetic substates of trapped atoms coupled by a radio-frequency field. We discuss their theoretical foundations and point out fundamental advantages over purely based on static fields. The enhanced flexibility enables one to implement numerous configurations, including double wells, Mach-Zehnder, Sagnac interferometers which even allows for internal state-dependent atom manipulation. These can be realized using simple highly integrated...
We present a quantitative study of roughness in the magnitude magnetic fieldproduced by current carrying microwire, i.e. trapping potential for paramagnetic atoms.We show that this arises from deviations wire flow due to geometric fluctuations edges : measurement potentialusing cold trapped atoms agrees with computed edge scanning electronmicroscope.
We demonstrate that virtual excitations of higher radial modes in an atomic Bose gas a tightly confining waveguide result effective three-body collisions violate integrability this quasi-one-dimensional quantum system and give rise to thermalization. The estimated thermalization rates are consistent with recent experimental results quasi-1D dynamics ultracold atoms.
We measure the two-point density correlation function of freely expanding quasicondensates in weakly interacting quasi-one-dimensional (1D) regime. While initially suppressed trap, fluctuations emerge gradually during expansion as a result initial phase present trapped quasicondensate. Asymptotically, they are governed by thermal coherence length system. Our measurements take place an intermediate regime where correlations related to near-field diffraction effects and anomalous play...
The 7.8 eV nuclear isomer transition in 229 Thorium has been suggested as an etalon a new type of optical frequency standard. Here we discuss the construction "solid-state clock" from nuclei implanted into single crystals transparent vacuum ultraviolet range. We investigate crystal-induced line shifts and broadening effects for specific system Calcium fluoride. At liquid Nitrogen temperatures, clock performance will be limited by decoherence due to magnetic coupling nucleus neighboring...
We investigate theoretically the evolution of two-point density correlation function a low-dimensional ultracold Bose gas after release from tight transverse confinement. In course expansion thermal and quantum fluctuations present in trapped systems transform into fluctuations. For case free ballistic relevant to current experiments, we simple analytical relations between spectrum ``density ripples'' functions original confined systems. analyze several physical regimes, including weakly...
Abstract The Ramsey interferometer is a prime example of precise control at the quantum level. It usually implemented using internal states atoms, molecules or ions, for which powerful manipulation procedures are now available. Whether it possible to external degrees freedom more complex, interacting many-body systems this level remained an open question. Here we demonstrate two-pulse Ramsey-type non-classical motional Bose–Einstein condensate in anharmonic trap. sequences used manipulate...
We realize a one-dimensional Josephson junction using quantum degenerate Bose gases in tunable double well potential on an atom chip. Matter wave interferometry gives direct access to the relative phase field, which reflects interplay of thermally driven fluctuations and locking due tunneling. The thermal equilibrium state is characterized by probing full statistical distribution function two-point correlation. Comparison stochastic model allows us measure coupling strength temperature hence...