A5028614244- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Atomic and Molecular Physics
- Advanced Thermodynamics and Statistical Mechanics
- High-pressure geophysics and materials
- Graphene research and applications
- Surface and Thin Film Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Nuclear Physics and Applications
- Quantum Electrodynamics and Casimir Effect
- Thermal Radiation and Cooling Technologies
- Electronic and Structural Properties of Oxides
- Quantum, superfluid, helium dynamics
- Quantum and electron transport phenomena
- Crystallography and Radiation Phenomena
- Ion-surface interactions and analysis
- X-ray Spectroscopy and Fluorescence Analysis
- Mechanical and Optical Resonators
- Boron and Carbon Nanomaterials Research
- Photonic Crystal and Fiber Optics
- Advanced X-ray Imaging Techniques
- nanoparticles nucleation surface interactions
- Topological Materials and Phenomena
- Advanced Electron Microscopy Techniques and Applications
- Quantum Information and Cryptography
Vienna Center for Quantum Science and Technology
2017-2024
University of Vienna
2017-2024
Université Paris-Saclay
2015-2023
Institut des Sciences Moléculaires d'Orsay
2013-2023
Centre National de la Recherche Scientifique
2013-2023
Austrian Academy of Sciences
2022
Centre Hospitalier d'Orsay
2021
Université Paris-Sud
2013-2020
Austrian Economics Center
2018-2019
Soil Science Research Unit
2014
Abstract Feedback control mechanisms are ubiquitous in science and technology, play an essential role regulating physical, biological engineering systems. The standard second law of thermodynamics does not hold the presence measurement feedback. Most studies so far have extended for discrete, Markovian feedback protocols; however, non-Markovian is omnipresent processes where signal applied with a non-negligible delay. Here, we experimentally investigate continuous, time-delayed using motion...
Fluctuation theorems are fundamental extensions of the second law thermodynamics for small nonequilibrium systems. While work and heat equally important forms energy exchange, fluctuation relations have not been experimentally assessed generic situation simultaneous mechanical thermal changes. Thermal driving is indeed generally slow more difficult to realize than driving. Here, we use feedback cooling techniques implement fast controlled temperature variations an underdamped levitated...
A grazing incidence fast atom diffraction (GIFAD or FAD) setup, installed on a molecular beam epitaxy chamber, has been used to characterize the ${\ensuremath{\beta}}_{2}(2\ifmmode\times\else\texttimes\fi{}4)$ reconstruction of GaAs(001) surface at $530{\phantom{\rule{0.16em}{0ex}}}^{\ensuremath{\circ}}\mathrm{C}$ under an ${\mathrm{As}}_{4}$ overpressure. Using 400-eV ${}^{4}\mathrm{He}$ beam, high-resolution patterns with up eighty well-resolved orders are observed simultaneously,...
Many experiments in the field of optical levitation with nanoparticles today are limited by available technologies for particle loading. Here, we introduce a loading method that solves main challenges, namely deterministic positioning particles and clean delivery at ultra-high vacuum levels as required quantum experiments. We demonstrate efficient loading, positioning, repositioning range 100–755 nm diameter into different lattice sites standing wave trap, well direct 143–365 vacuum, down to...
By controlling the variance of radiation pressure exerted on an optically trapped microsphere in real time, we engineer temperature protocols that shortcut thermal relaxation when transferring from one equilibrium state to another. We identify entropic footprint such accelerated transfers and derive optimal either minimize production entropy for a given transfer duration or accelerate cost as much possible. Optimizing trade-off yields time-entropy bounds put speed limits thermalization...
A Grazing Incidence Fast Atom Diffraction (GIFAD) system has been mounted on a commercial molecular beam epitaxy chamber and used to monitor GaAs growth in real-time. In contrast the conventionally Reflection High Energy Electron Diffraction, all GIFAD diffraction orders oscillate phase, with change intensity related diffuse scattering at step edges. We show that scattered integrated over Laue circle is robust method periodic surface roughness during layer-by-layer growth, oscillation phase...
We present a grazing incidence fast atom diffraction (GIFAD) study of monolayer graphene on 6H-SiC(0001). This system shows Moiré-like 13 × superlattice above the reconstructed carbon buffer layer. The averaging property GIFAD results in electronic and geometric corrugations that are well decoupled; honeycomb corrugation is only observed with incident beam parallel to zigzag direction while arising from revealed along armchair direction. Full-quantum calculations patterns show very high...
We report on the experimental observation and theoretical study of bound state resonances in fast atom diffraction at surfaces. In our studies, $^{4}\mathrm{He}$ beam has been scattered from a high-quality LiF(001) surface very small grazing incidence angles. this regime, reciprocal lattice vector exchange with allows transient trapping 0.3--0.5 keV projectiles into quasistationary states by attractive atom-surface potential well which is only 10 meV deep. Analysis linewidths calculated...
The diffraction of fast atoms at crystal surfaces is ideal for a detailed investigation the surface electronic density. However, instead sharp spots, most experiments show elongated streaks characteristic inelastic diffraction. This paper describes these profiles in terms individual collisions with taking place along projectile trajectory and leading to vibrational excitation local Debye oscillator. A quasielastic regime where only one event contributes identified as well mixed...
Causality is an important assumption underlying nonequilibrium generalizations of the second law thermodynamics known as fluctuation relations. We here experimentally study statistical properties work and entropy production for optically trapped, underdamped nanoparticle continuously subjected to a time-delayed feedback control. Whereas non-Markovian depends on past position particle forward trajectory, it its future time-reversed path, therefore acausal. In steady-state regime, we show that...
In the elastic regime, GIFAD is equivalent to TEAS with an effective energy <italic>E</italic><sub>⊥</sub> between 1 meV and eV providing a high sensitivity topology attractive forces. The inelastic regime merges classical limit still in development.
We study the diffraction of neutral hydrogen atoms through suspended single-layer graphene using molecular dynamics simulations based on density functional theory. Although have to overcome a transmission barrier, we find that de Broglie wave function for H at 80 eV has high probability be coherently transmitted about 18% area, contrary case He. propose an experiment realize natural hexagon lattice period 246 pm, leading more than 400-fold increase in beam separation split atomic compared...
Abstract The objective of the proposed macroscopic quantum resonators (MAQRO) mission is to harness space for achieving long free-fall times, extreme vacuum, nano-gravity, and cryogenic temperatures test foundations physics in experiments at interface with gravity. Developing necessary technologies, required sensitivities providing isolation systems from their environment will lay path developing novel sensors. Earlier studies showed that proposal feasible but several critical challenges...
For energetic atomic beams grazingly incident at the surface along low index directions, fast motion parallel to and slow perpendicular lead quantum diffraction pattern in scattered beam. In this experimental theoretical joint study we show that when beam is misaligned with respect an axial channel, characteristic deformation of reflects overall deflection from specular direction. The maximum for azimuthal misalignment angles close rainbow angle how effect can be explained detailed balance...
The semiclassical perturbation method developed by Henkel et al. [J. Phys. II 4, 1955 (1994)] to model cold-atom diffraction optical standing waves, is applied the of fast atoms on crystal surfaces at grazing incidence (GIFAD or FAD). We first show that interaction time and length embedded in obliquity factor well suited explain transition from three-dimensional two-dimensional (2D) diffraction. situation a slightly misaligned primary beam, corresponding oblique effective 2D system,...
Monolayer epitaxial graphene grown on 6H-SiC(0001) was recently investigated by grazing-incidence fast-atom diffraction and analyzed with an ab initio electronic density calculation exact atomic methods. With these results as a reference, the hard-corrugated-wall model (HCW) is used complementary analytic approach to link binary potentials observed corrugation. The main result that HCW reproduces macroscopic corrugation of moir\'e pattern quantitative level, suggesting soft-wall corrections...
Ne atoms with energies of ≤3 keV are diffracted under grazing angles incidence from a LiF(001) surface. For small momentum component the incident beam perpendicular to surface, we observe an increase in elastic rainbow angle together broadening inelastic scattering profile. We interpret these two effects as refraction atomic wave attractive part surface potential. use fast, rigorous dynamical diffraction calculation find projectile-surface potential model that enables quantitative...
Large deviation theory offers a powerful and general statistical framework to study the asymptotic dynamical properties of rare events. The application formalism concrete experimental situations is, however, often restricted by finite statistics. Data might not suffice reach regime or judge whether large estimators converge at all. We here experimentally stochastic work heat levitated nanoparticle subjected nonequilibrium feedback control. This setting allows us determine for each quantity...
Elastic diffraction of fast atoms at crystal surfaces under grazing incidence $\ensuremath{\theta}\ensuremath{\approx}1$\ifmmode^\circ\else\textdegree\fi{} has strong similarities with atomic thermal energies discovered almost hundred years ago. Here, we focus on the polar scattering profile, which does not exhibit features but shows well-defined elastic and inelastic components that are found to be essentially independent crystallographic axis. The width...
Grazing incidence fast-atom diffraction (GIFAD) uses keV atoms to probe the topmost layer of crystalline surfaces. The are scattered by potential energy landscape surface onto elastic spots located at Bragg angles and on Laue circle. However, transfer a significant momentum surface, giving rise possible phonon excitation. This causes inelastic intensity spread above below circle along direction normal. relative contribution is well fitted Debye-Waller model adapted GIFAD, but composite...
Photocleavable tags (PCTs) have the potential for excellent spatio-temporal control over release of subunits complex molecules.
We investigate the influence of temperature in Fast Atom Diffraction at surfaces. The inelastic profiles broaden rapidly while elastic one is constant but its intensity decreases with a Debye-Waller factor adapted to grazing incidences.
Charge reduction and neutralization of electro-sprayed peptides are realized by selective gas-phase photocleavage tailored covalent tags. The concept is demonstrated with four model in positive negative ion modes tagged insulin as the largest construct.