A5004034712- Atomic and Subatomic Physics Research
- Cold Atom Physics and Bose-Einstein Condensates
- Advanced Frequency and Time Standards
- Quantum optics and atomic interactions
- Atomic and Molecular Physics
- Spectroscopy and Laser Applications
- Nuclear physics research studies
- Scientific Measurement and Uncertainty Evaluation
- Radiation Detection and Scintillator Technologies
- Advanced Fiber Laser Technologies
- Nuclear Physics and Applications
- Muon and positron interactions and applications
- Advanced MRI Techniques and Applications
- Laser-Matter Interactions and Applications
- Inorganic Fluorides and Related Compounds
- Luminescence Properties of Advanced Materials
- Crystallography and Radiation Phenomena
- advanced mathematical theories
- Global Political and Economic Relations
- Superconducting Materials and Applications
- Particle physics theoretical and experimental studies
- Neutrino Physics Research
- Microbial Metabolic Engineering and Bioproduction
- Photonic and Optical Devices
- Advanced Chemical Physics Studies
TU Wien
2015-2025
Timiryazev Institute of Plant Physiology
2025
Vienna Center for Quantum Science and Technology
2013-2024
Physikalisch-Technische Bundesanstalt
2024
Institute of Physics
2022
Nicolaus Copernicus University
2022
Peter the Great St. Petersburg Polytechnic University
2005-2021
Wolfgang Pauli Institute
2011-2020
University of Vienna
2011-2018
Centre National de Recherches Météorologiques
2005
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 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...
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 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...
The <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mn>8</a:mn><a:mtext>−</a:mtext><a:mi>eV</a:mi></a:mrow></a:math> first nuclear excited state in <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mmultiscripts><b:mi>Th</b:mi><b:mprescripts/><b:none/><b:mn>229</b:mn></b:mmultiscripts></b:math> is a candidate for implementing clock. Doping <c:math...
The (229)thorium isotope presents an extremely low-energy isomer state of the nucleus which is expected around 7.8 eV, in vacuum ultraviolet (VUV) regime. This unique system may bridge between atomic and nuclear physics, enabling coherent manipulation precision spectroscopy quantum states using laser light. It has been proposed to implant into VUV transparent crystal matrices facilitate possibly realize a solid-state clock. In this work, we validate feasibility approach by computer modelling...
We aim to perform direct optical spectroscopy of the Th-229 nuclear isomer measure its energy and lifetime, demonstrate coupling nucleus. To this end, we develop Th-doped CaF2 crystals, which are transparent at anticipated wavelength. Such crystals illuminated by tunable VUV undulator radiation for excitation isomer. scan a 5 sigma region around assumed 7.8(5) eV vary time in sequential scans between 30 600 seconds. Suffering from an unforeseen strong photoluminescence crystal, experiment is...
Direct laser excitation of the lowest known nuclear excited state in $^{229}\mathrm{Th}$ has been a long-standing objective. It is generally assumed that reaching this goal would require considerably reduced uncertainty isomer's energy compared to presently adopted value $(7.8\ifmmode\pm\else\textpm\fi{}0.5)\text{ }\text{ }\mathrm{eV}$. Here we present direct scheme for $^{229m}\mathrm{Th}$, which circumvents requirement. The proposed makes use already existing technology and therefore paves...
Optical atomic clocks$^{1,2}$ use electronic energy levels to precisely keep track of time. A clock based on nuclear promises a next-generation platform for precision metrology and fundamental physics studies. Thorium-229 nuclei exhibit uniquely low transition within reach state-of-the-art vacuum ultraviolet (VUV) laser light sources have therefore been proposed construction the first clock$^{3,4}$. However, quantum state-resolved spectroscopy $^{229m}$Th isomer determine underlying...
Continuous superradiance using a narrow optical transition has the potential to improve short-term stability of state-of-the-art clocks. Even though pulsed superradiant emission on <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mi>mHz</a:mi></a:math> linewidth clock been shown, true continuous operation, without Fourier limitation, turned out be extremely challenging. The trade-off between maintaining high atomic flux while minimizing decoherence effects presents significant...
Recently, several theoretical proposals addressed the generation of an active optical frequency standard based on atomic ensembles trapped in lattice potential inside resonator. Using atoms with a narrow linewidth transition and population inversion together ``bad'' cavity allows us to realize super-radiant photon emission regime. These schemes reduce influence mechanical or thermal vibrations mirrors emitted frequency, overcoming current limitation passive standards. The coherence time...
We report on light shift and broadening in the atomic-motion-induced Ramsey narrowing of dark resonances prepared alkali-metal vapors contained wall-coated cells without buffer gas. The is due to free motion polarized atomic spins out optical interaction region before spin relaxation. As a consequence this effect, we observe resonance linewidth as well reduction ground states' when volume decreases at constant intensity. results can be intuitively interpreted dilution intensity effect...
We propose an approach to all-optical frequency standard design, based on a counterintuitive combination of the coherent population trapping effect and signal discrimination at maximum absorption for probe radiation. The short-term stability such can achieve level ${10}^{\ensuremath{-}14}∕\sqrt{\ensuremath{\tau}}$. physics beyond this is dark resonance splitting caused by interaction nuclear magnetic moment with external field.
We propose a simple approach to measure the energy of few-eV isomeric state in $^{229}\mathrm{Th}$. To this end, $^{233}\mathrm{U}$ nuclei are doped into VUV-transparent crystals, where they undergo $\ensuremath{\alpha}$ decay $^{229}\mathrm{Th}$, and, with probability 2%, populate state. These $^{229\mathrm{m}}\mathrm{Th}$ may nuclear ground under emission sought-after VUV $\ensuremath{\gamma}$ ray, whose wavelength can be determined spectrometer. Based on measurements optical transmission...
The Thorium-229 isotope features a nuclear isomer state with an extremely low energy. currently most accepted energy value, 7.8 +- 0.5 eV, was obtained from indirect measurement using NASA x-ray microcalorimeter instrumental resolution 26 eV. We study, how state-of-the-art magnetic metallic microcalorimeters down to few eV can be used measure the In particular, resolving 29.18 keV doublet in \gamma-spectrum following \alpha-decay of Uranium-233, corresponding decay into ground and state,...
It has been proposed to use magnetically trapped atomic ensembles enhance the interrogation time in microwave clocks. To mitigate perturbing effects of magnetic trap, near-magic-field configurations are employed, where involved clock transition becomes independent atom's potential energy first order. Still, higher order a dominating source for dephasing, limiting performance this approach. Here we propose simple method cancel dependence both and second order, using weak radio-frequency...
We investigate experimentally and theoretically the Coherent Population Trapping (CPT) effect occurring in 87Rb D1 line due to interaction with linearly polarized laser light (lin||lin CPT). In this configuration coherence has a quadrupol like nature is strongly influenced by hyperfine structure of excited state; consequently quantum interference between CPT states an essential feature scheme. study lin||lin signal as function optical detuning. The comparison experimental theoretical results...
We consider various approaches to the creation of a high-stability active optical frequency standard, where atomic ensemble itself produces highly stable and accurate signal. The short-time stability such standards may overcome lasers stabilized macroscopic cavities which are used as local oscillators in modern standard systems. main idea is create "superradiant" laser operating deep bad cavity regime, decay rate field significantly exceeds decoherence lasing transition. Two towards...
We studied theoretically a coherent population trapping resonance formation in cylindrical cell without buffer gas irradiated by narrow laser beam. take into account non-zero probabilities of elastic ("specular") and inelastic ("sticking") collision between the atom wall. have developed theoretical model based on averaging over random Ramsey pulse sequences times that spent out It is shown shape line depends probability collision.
Superradiant active clocks operating on narrow linewidth clock transitions are predicted to achieve precision orders of magnitude higher than any currently existing optical atomic clocks. We introduce a theory superradiant lasing and implement it for the example 40Ca atoms. The presented model, however, is valid two- or three-level system in an lattice. perform feasibility analysis suggest set parameters experimental fulfillment Ca. Moreover, we present overview different magic wavelengths...
A suitable scheme to continuously create inversion on an optical clock transition with negligible perturbation is a key missing ingredient required build active atomic clock. Repumping of the atoms narrow typically needs several pump lasers in multi step process involving auxiliary levels. In general this creates large effective level shifts and line broadening, strongly limiting accuracy. Here we present extensive theoretical study for realistic multi-level implementation search parameter...