296 results on '"Ulbricht H"'
Search Results
102. Bedeutung der Sporenbildung bei humanpathogen Pilzen.
- Author
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Ulbricht, H. M.
- Published
- 2003
103. Häufigkeit von FuBmykosen bei Typ-1 Diabetikern.
- Author
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Hensel, J., Mayser, P., Thoma, W., Podobinska, M., Geiger, M., Ulbricht, H., and Haak, T.
- Published
- 2003
104. ChemInform Abstract: 2-Amino Oxazoles as Potential H-Bonding Agents in the Virus Chemotherapy Research. Part 4. Pharmacokinetics, Pharmacological, and Toxicological Properties of 2-Guanidino-4,5-dipropyloxazole Hydrochloride.
- Author
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HOFFMANN, H., HILLESHEIM, H. G., AMLACHER, R., KIRCHNER, E., HAERTL, A., HORN, U., GUETTNER, J., KNAPPE, H., and ULBRICHT, H.
- Published
- 1994
- Full Text
- View/download PDF
105. Handbuch für die gesamte Holzindustrie.
- Author
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Ulbricht, H. J.
- Published
- 1955
106. A way forward for fundamental physics in space
- Author
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A. Bassi, L. Cacciapuoti, S. Capozziello, S. Dell’Agnello, E. Diamanti, D. Giulini, L. Iess, P. Jetzer, S. K. Joshi, A. Landragin, C. Le Poncin-Lafitte, E. Rasel, A. Roura, C. Salomon, H. Ulbricht, Bassi, A, Cacciapuoti, L, Capozziello, S, Dell'Agnello, S, Diamanti, E, Giulini, D, Iess, L, Jetzer, P, Joshi, S K, Landragin, A, Poncin-Lafitte, C Le, Rasel, E, Roura, A, Salomon, C, and Ulbricht, H
- Subjects
tests of the equivalence principle ,fundamental physics in space ,Physics and Astronomy (miscellaneous) ,atomic clocks ,tests of quantum mechanics ,Materials Science (miscellaneous) ,optical links in space ,matter-wave interferometry ,Medicine (miscellaneous) ,dark-matter and dark-energy searches ,cold atoms ,Experiments in space ,Agricultural and Biological Sciences (miscellaneous) ,Biochemistry, Genetics and Molecular Biology (miscellaneous) ,Energy decoherence ,tests of general relativity ,Space and Planetary Science ,Dark energy ,Dark matter ,atom interferometry ,ddc:530 ,Cold atoms ,Dewey Decimal Classification::500 | Naturwissenschaften::530 | Physik ,Equivalence principles - Abstract
Space-based research can provide a major leap forward in the study of key open questions in the fundamental physics domain. They include the validity of Einstein’s Equivalence principle, the origin and the nature of dark matter and dark energy, decoherence and collapse models in quantum mechanics, and the physics of quantum many-body systems. Cold-atom sensors and quantum technologies have drastically changed the approach to precision measurements. Atomic clocks and atom interferometers as well as classical and quantum links can be used to measure tiny variations of the space-time metric, elusive accelerations, and faint forces to test our knowledge of the physical laws ruling the Universe. In space, such instruments can benefit from unique conditions that allow improving both their precision and the signal to be measured. In this paper, we discuss the scientific priorities of a space-based research program in fundamental physics.
- Published
- 2022
107. Present status and future challenges of non-interferometric tests of collapse models
- Author
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Matteo Carlesso, Sandro Donadi, Luca Ferialdi, Mauro Paternostro, Hendrik Ulbricht, Angelo Bassi, Carlesso, M., Donadi, S., Ferialdi, L., Paternostro, M., Ulbricht, H., and Bassi, A.
- Subjects
Quantum Physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Atomic Physics (physics.atom-ph) ,FOS: Physical sciences ,General Physics and Astronomy ,General Relativity and Quantum Cosmology (gr-qc) ,Physics and Astronomy(all) ,General Relativity and Quantum Cosmology ,High Energy Physics - Experiment ,Physics - Atomic Physics ,High Energy Physics - Experiment (hep-ex) ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,Quantum Physics (quant-ph) ,Quantum foundations - Abstract
The superposition principle is the cornerstone of quantum mechanics, leading to a variety of genuinely quantum effects. Whether the principle applies also to macroscopic systems or, instead, there is a progressive breakdown when moving to larger scales, is a fundamental and still open question. Spontaneous wavefunction collapse models predict the latter option, thus questioning the universality of quantum mechanics. Technological advances allow to challenge collapse models and the quantum superposition principle more and more with a variety of different experiments. Among them, non-interferometric experiments proved to be the most effective in testing these models. We provide an overview of such experiments, including cold atoms, optomechanical systems, X-rays detection, bulk heating as well as comparisons with cosmological observations. We also discuss avenues for future dedicated experiments, which aim at further testing collapse models and the validity of quantum mechanics.
- Published
- 2022
108. Quantum Physics in Space
- Author
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Belenchia, Alessio, Carlesso, Matteo, Bayraktar, Ömer, Dequal, Daniele, Derkach, Ivan, Gasbarri, Giulio, Herr, Waldemar, Li, Ying Lia, Rademacher, Markus, Sidhu, Jasminder, Oi, Daniel K.L., Seidel, Stephan T., Kaltenbaek, Rainer, Marquardt, Christoph, Ulbricht, Hendrik, Usenko, Vladyslav C., Wörner, Lisa, Xuereb, André, Paternostro, Mauro, Bassi, Angelo, Belenchia, A., Carlesso, M., Bayraktar, O., Dequal, D., Derkach, I., Gasbarri, G., Herr, W., Li, Y. L., Rademacher, M., Sidhu, J., Oi, D. K. L., Seidel, S. T., Kaltenbaek, R., Marquardt, C., Ulbricht, H., Usenko, V. C., Worner, L., Xuereb, A., Paternostro, M., and Bassi, A.
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Quantum physic ,Quantum Physics ,FOS: Physical sciences ,General Physics and Astronomy ,Space ,General Relativity and Quantum Cosmology (gr-qc) ,Quantum computing ,Space Physics (physics.space-ph) ,General Relativity and Quantum Cosmology ,Quantum technology ,High Energy Physics - Experiment ,High Energy Physics - Experiment (hep-ex) ,Physics - Space Physics ,Quantum Gases (cond-mat.quant-gas) ,Quantum physics ,Quantum theory ,Quantum Physics (quant-ph) ,Condensed Matter - Quantum Gases ,QC - Abstract
Advances in quantum technologies are giving rise to a revolution in the way fundamental physics questions are explored at the empirical level. At the same time, they are the seeds for future disruptive technological applications of quantum physics. Remarkably, a space-based environment may open many new avenues for exploring and employing quantum physics and technologies. Recently, space missions employing quantum technologies for fundamental or applied studies have been proposed and implemented with stunning results. The combination of quantum physics and its space application is the focus of this review: we cover both the fundamental scientific questions that can be tackled with quantum technologies in space and the possible implementation of these technologies for a variety of academic and commercial purposes., peer-reviewed
- Published
- 2021
109. Gravitational Decoherence and the Possibility of Its Interferometric Detection
- Author
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Angelo Bassi, Lorenzo Asprea, Giulio Gasbarri, Hendrik Ulbricht, Asprea, L., Bassi, A., Ulbricht, H., and Gasbarri, G.
- Subjects
Physics ,Quantum decoherence ,Quantum dynamics ,Scalar (physics) ,General Physics and Astronomy ,Energy–momentum relation ,Quantum Mechanic ,01 natural sciences ,Gravitation ,Classical mechanics ,Gravitational field ,Quantum Mechanics ,Gravitational Decoherence ,0103 physical sciences ,Master equation ,Bosonic field ,010306 general physics - Abstract
We present a general master equation describing the quantum dynamics of a scalar bosonic field interacting with an external weak and stochastic gravitational field. The dynamics predicts decoherence both in position and in energy momentum. We show how the master equation reproduces, thus generalizing, the previous results in the literature by taking appropriate limits. We estimate the effect of gravitational decoherence in atom interferometers, providing also a straightforward way to assess the magnitude of the effect.
- Published
- 2021
110. Smoothly breaking unitarity : studying spontaneous collapse using two entangled, tuneable, coherent amplifiers
- Author
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Reep, T.H.A. van der, Oosterkamp, T.H., Ulbricht, H., Steele, G.A., Eliel, E.R., Orrit, M.A.G.J., Dood, M.J.A. de, and Leiden University
- Subjects
TWPA ,Superconducting quantum optics ,Wavefunction collapse ,Quantum-to-classical transition ,Spontaneous collapse ,Quantum measurement problem ,Single-photon interferometer ,Microwave optics ,Travelling-wave parametric amplifier ,Non-linear waveguide - Abstract
The Copenhagen interpretation of quantum mechanics states that a measurement collapses a wavefunction onto an eigenstate of the corresponding measurement operator. This causes a quantum mechanical wavefunction to break its unitary evolution described by the Schrödinger equation and is the source of the quantum measurement problem. In this thesis we take the first steps to an experiment that might shed light on this century-old problem. We envision a single-microwave-photon interferometer that has a travelling-wave parametric amplifier (TWPA) added to each of its arms. We wonder if the process of amplification of the quantum state causes the wavefunction to collapse, as it might turn into a detector while smoothly increasing the amplifier's gain. To this end we introduce necessary concepts from the field of microwave engineering. Then, we develop a quantum theory to describe TWPAs. This is followed by preliminary calculations on the expected interference visibility of the envisioned interferometer as a function of amplifier gain and losses. Furthermore, we describe how wavefunction collapse might reveal itself in the experimental results. Finally, the thesis describes our efforts to develop a low-loss TWPA based on Josephson junctions.
- Published
- 2019
111. Antiphytovirale Verbindungen mit nichtzyklischer Azin-Struktur.
- Author
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Schuster, G., Heinisch, L., Schulze, W., Ulbricht, H., and Willitzer, H.
- Published
- 1984
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112. Quantum-limited estimation of continuous spontaneous localization
- Author
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Matteo Carlesso, Mauro Paternostro, Angelo Bassi, S. McMillen, Matteo Brunelli, Hendrik Ulbricht, Matteo G. A. Paris, Mcmillen, S., Brunelli, M., Carlesso, Matteo, Bassi, Angelo, Ulbricht, H., Paris, M. G. A., and Paternostro, M.
- Subjects
Electromagnetic field ,Physics ,Quantum Physics ,Estimation theory ,Collapse models ,FOS: Physical sciences ,Physics::Optics ,Opto-mechanics ,01 natural sciences ,010305 fluids & plasmas ,Resonator ,Formalism (philosophy of mathematics) ,Direct-conversion receiver ,Collapse model ,Quantum mechanics ,0103 physical sciences ,Statistical physics ,Quantum Physics (quant-ph) ,010306 general physics ,Quantum - Abstract
We apply the formalism of quantum estimation theory to extract information about potential collapse mechanisms of the continuous spontaneous localisation (CSL) form. In order to estimate the strength with which the field responsible for the CSL mechanism couples to massive systems, we consider the optomechanical interaction between a mechanical resonator and a cavity field. Our estimation strategy passes through the probing of either the state of the oscillator or that of the electromagnetic field that drives its motion. In particular, we concentrate on all-optical measurements, such as homodyne and heterodyne measurements. We also compare the performances of such strategies with those of a spin-assisted optomechanical system, where the estimation of the CSL parameter is performed through time-gated spin-like measurements., 8 pages, 3 figures, RevTeX4-1; accepted for publication in Phys. Rev. A
- Published
- 2017
113. Proposal for a Noninterferometric Test of Collapse Models in Optomechanical Systems
- Author
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Angelo Bassi, Mauro Paternostro, Mohammad Bahrami, Hendrik Ulbricht, Bahrami, Mohammad, Paternostro, M., Bassi, Angelo, and Ulbricht, H.
- Subjects
Physics ,Quantum Physics ,medicine.medical_specialty ,Quantum dynamics ,Physics, Quantum Physics ,Quantum superposition ,General Physics and Astronomy ,Physics and Astronomy(all) ,Open quantum system ,Quantum probability ,Theoretical physics ,Quantum nanoscience ,medicine ,Statistical physics ,Quantum information science ,Wave function collapse ,Quantum - Abstract
The test of modifications to quantum mechanics aimed at identifying the fundamental reasons behind the unobservability of quantum mechanical superpositions at the macroscale is a crucial goal of modern quantum mechanics. Within the context of collapse models, current proposals based on interferometric techniques for their falsification are far from the experimental state of the art. Here we discuss an alternative approach to the testing of quantum collapse models that, by bypassing the need for the preparation of quantum superposition states might help us addressing nonlinear stochastic mechanisms such as the one at the basis of the continuous spontaneous localization model.
- Published
- 2014
114. Testing the quantum superposition principle in the frequency domain
- Author
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Hendrik Ulbricht, Angelo Bassi, Mohammad Bahrami, Bahrami, Mohammad, Bassi, Angelo, and Ulbricht, H.
- Subjects
Chemical Physics (physics.chem-ph) ,Physics ,Quantum Physics ,Quantum decoherence ,Atomic Physics (physics.atom-ph) ,Quantum superposition ,FOS: Physical sciences ,Equations of motion ,Collapse (topology) ,Magnitude (mathematics) ,Atomic and Molecular Physics, and Optics ,Physics - Atomic Physics ,Superposition principle ,Classical mechanics ,Physics - Chemical Physics ,Atomic and Molecular Physics ,Frequency domain ,Physics - Atomic and Molecular Clusters ,and Optics ,Quantum Physics (quant-ph) ,Atomic and Molecular Clusters (physics.atm-clus) ,Spectroscopy - Abstract
New technological developments allow to explore the quantum properties of very complex systems, bringing the question of whether also macroscopic systems share such features, within experimental reach. The interest in this question is increased by the fact that, on the theory side, many suggest that the quantum superposition principle is not exact, departures from it being the larger, the more macroscopic the system. Here we propose a novel way to test the possible violation of the superposition principle, by analyzing its effect on the spectral properties of a generic two-level system. We will show that spectral lines shapes are modified, if the superposition principle is violated, and we quantify the magnitude of the violation. We show how this effect can be distinguished from that of standard environmental noises. We argue that accurate enough spectroscopic experiments are within reach, with current technology., comments are welcome!
- Published
- 2014
115. Narrowing the Parameter Space of Collapse Models with Ultracold Layered Force Sensors
- Author
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Andrea Chiasera, Sandro Varas, Hendrik Ulbricht, Angelo Bassi, Paolo Falferi, Rodolfo Mezzena, Basin Margesin, Matteo Carlesso, Andrea Vinante, Vinante, A., Carlesso, M., Bassi, A., Chiasera, A., Varas, S., Falferi, P., Margesin, B., Mezzena, R., and Ulbricht, H.
- Subjects
Physics ,Quantum Physics ,Reduction (recursion theory) ,Characteristic length ,foundations quantum mechanics ,quantum-to-classical transition ,collapse models ,FOS: Physical sciences ,General Physics and Astronomy ,Collapse (topology) ,foundations quantum mechanic ,Parameter space ,SQUID ,01 natural sciences ,Noise (electronics) ,Quantum technology ,Quality (physics) ,Quantum mechanics ,0103 physical sciences ,Quantum Physics (quant-ph) ,microcantilever ,010306 general physics ,Order of magnitude - Abstract
Despite the unquestionable empirical success of quantum theory, witnessed by the recent uprising of quantum technologies, the debate on how to reconcile the theory with the macroscopic classical world is still open. Spontaneous collapse models are one of the few testable solutions so far proposed. In particular, the continuous spontaneous localization (CSL) model has become subject of an intense experimental research. Experiments looking for the universal force noise predicted by CSL in ultrasensitive mechanical resonators have recently set the strongest unambiguous bounds on CSL; further improving these experiments by direct reduction of mechanical noise is technically challenging. Here, we implement a recently proposed alternative strategy, that aims at enhancing the CSL noise by exploiting a multilayer test mass attached on a high quality factor microcantilever. The test mass is specifically designed to enhance the effect of CSL noise at the characteristic length $r_c=10^{-7}$ m. The measurements are in good agreement with pure thermal motion for temperatures down to 100 mK. From the absence of excess noise we infer a new bound on the collapse rate at the characteristic length $r_c=10^{-7}$ m, which improves over previous mechanical experiments by more than one order of magnitude. Our results are explicitly challenging a well-motivated region of the CSL parameter space proposed by Adler., Comment: 9 pages, 7 figures
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116. Testing the gravitational field generated by a quantum superposition
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Hendrik Ulbricht, Mauro Paternostro, Angelo Bassi, Matteo Carlesso, Carlesso, M, Bassi, A, Paternostro, M, and Ulbricht, H
- Subjects
Quantum decoherence ,Quantum superposition ,Gravity ,General Physics and Astronomy ,FOS: Physical sciences ,General Relativity and Quantum Cosmology (gr-qc) ,Physics and Astronomy(all) ,01 natural sciences ,General Relativity and Quantum Cosmology ,010305 fluids & plasmas ,Gravitation ,Superposition principle ,Gravitational field ,0103 physical sciences ,Quantum system ,010306 general physics ,Quantum ,Physics ,Quantum Physics ,Quantum gravity ,classical gravity ,Optomechanics ,optomechanics ,Classical mechanics ,quantum gravity ,Quantum Physics (quant-ph) - Abstract
What gravitational field is generated by a massive quantum system in a spatial superposition? Despite decades of intensive theoretical and experimental research, we still do not know the answer. On the experimental side, the difficulty lies in the fact that gravity is weak and requires large masses to be detectable. However, it becomes increasingly difficult to generate spatial quantum superpositions for increasingly large masses, in light of the stronger environmental effects on such systems. Clearly, a delicate balance between the need for strong gravitational effects and weak decoherence should be found. We show that such a trade off could be achieved in an optomechanics scenario that allows to determine whether the gravitational field generated by a quantum system in a spatial superposition is in a coherent superposition or not. We estimate the magnitude of the effect and show that it offers perspectives for observability., Comment: This manuscript supersedes arXiv:1507.05733, upon which it builds. However. we decided to leave the latter on the arXiv in light of its own merits
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117. Amplification of electromagnetic fields by a rotating body.
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Braidotti MC, Vinante A, Cromb M, Sandakumar A, Faccio D, and Ulbricht H
- Abstract
In 1971, Zel'dovich predicted the amplification of electromagnetic (EM) waves scattered by a rotating metallic cylinder, gaining mechanical rotational energy from the body. This phenomenon was believed to be unobservable with electromagnetic fields due to technological difficulties in meeting the condition of amplification that is, the cylinder must rotate faster than the frequency of the incoming radiation. Here, we measure the amplification of an electromagnetic field, generated by a toroid LC-circuit, scattered by an aluminium cylinder spinning in the toroid gap. We show that when the Zel'dovich condition is met, the resistance induced by the cylinder becomes negative implying amplification of the incoming EM fields. These results reveal the connection between the concept of induction generators and the physics of this fundamental physics effect and open new prospects towards testing the Zel'dovich mechanism in the quantum regime, as well as related quantum friction effects., (© 2024. The Author(s).)
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- 2024
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118. Measuring gravity with milligram levitated masses.
- Author
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Fuchs TM, Uitenbroek DG, Plugge J, van Halteren N, van Soest JP, Vinante A, Ulbricht H, and Oosterkamp TH
- Abstract
Gravity differs from all other known fundamental forces because it is best described as a curvature of space-time. For that reason, it remains resistant to unifications with quantum theory. Gravitational interaction is fundamentally weak and becomes prominent only at macroscopic scales. This means, we do not know what happens to gravity in the microscopic regime where quantum effects dominate and whether quantum coherent effects of gravity become apparent. Levitated mechanical systems of mesoscopic size offer a probe of gravity, while still allowing quantum control over their motional state. This regime opens the possibility of table-top testing of quantum superposition and entanglement in gravitating systems. Here, we show gravitational coupling between a levitated submillimeter-scale magnetic particle inside a type I superconducting trap and kilogram source masses, placed approximately half a meter away. Our results extend gravity measurements to low gravitational forces of attonewton and underline the importance of levitated mechanical sensors.
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- 2024
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119. Mass-Independent Scheme to Test the Quantumness of a Massive Object.
- Author
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Das D, Home D, Ulbricht H, and Bose S
- Abstract
The search for empirical schemes to evidence the nonclassicality of large masses is a central quest of current research. However, practical schemes to witness the irreducible quantumness of an arbitrarily large mass are still lacking. To this end, we incorporate crucial modifications to the standard tools for probing the quantum violation of the pivotal classical notion of macrorealism (MR): while usual tests use the same measurement arrangement at successive times, here we use two different measurement arrangements. This yields a striking result: a mass-independent violation of MR is possible for harmonic oscillator systems. In fact, our adaptation enables probing quantum violations for literally any mass, momentum, and frequency. Moreover, coarse-grained position measurements at an accuracy much worse than the standard quantum limit, as well as knowing the relevant parameters only to this precision, without requiring them to be tuned, suffice for our proposal. These should drastically simplify the experimental effort in testing the nonclassicality of massive objects ranging from atomic ions to macroscopic mirrors in LIGO.
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- 2024
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120. Collapse Models: A Theoretical, Experimental and Philosophical Review.
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Bassi A, Dorato M, and Ulbricht H
- Abstract
In this paper, we review and connect the three essential conditions needed by the collapse model to achieve a complete and exact formulation, namely the theoretical, the experimental, and the ontological ones. These features correspond to the three parts of the paper. In any empirical science, the first two features are obviously connected but, as is well known, among the different formulations and interpretations of non-relativistic quantum mechanics, only collapse models, as the paper well illustrates with a richness of details, have experimental consequences. Finally, we show that a clarification of the ontological intimations of collapse models is needed for at least three reasons: (1) to respond to the indispensable task of answering the question 'what are collapse models (and in general any physical theory) about?'; (2) to achieve a deeper understanding of their different formulations; (3) to enlarge the panorama of possible readings of a theory, which historically has often played a fundamental heuristic role.
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- 2023
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121. Fascia training in patients undergoing allogeneic hematopoietic cell transplantation-a pilot study.
- Author
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Weigmann-Faßbender S, Ulbricht H, de Schultz M, Pawandenat C, Kunadt D, Wolff M, Giesemann N, Prate K, Schetelig J, Bornhäuser M, Stölzel F, Knauthe N, and Stölzel F
- Subjects
- Humans, Pilot Projects, Back Pain, Fascia, Quality of Life, Hematopoietic Stem Cell Transplantation
- Abstract
Purpose: Patients undergoing allogeneic hematopoietic cell transplantation (alloHCT) spend many weeks of treatment in an isolated environment with little room for exercise. Feasibility of a daily-performed, unassisted fascia-training program and its effects on back and foot pain, back flexibility, and quality of life were investigated., Methods: Eighteen patients receiving alloHCT were randomized to an intervention (IG: n = 9; 60.7 ± 9.2 years) or control group (CG: n = 9; 54.0 ± 15.5 years) and assessed from 1 week before to 3 weeks after transplantation (t0-t3). CG received standard care physical therapy, IG performed additionally fascia training for the back and feet twice daily. Back and foot pain, back flexibility, muscle tone, and quality of life were assessed for both IG and CG at baseline and three timepoints after alloHCT., Results: Fascia-training program was well accepted. No increase in hematoma formation was observed. IG reported a trend towards reduction in back pain from pre- to post-intervention (p = .074), whereas CG showed a slight increase in back pain at t3 (p = .257). IG also improved back flexibility (- 1.79 ± 5.5 cm; p = .397) while CG declined (+ 2.71 ± 5.6 cm; p = .167). No differences between groups were found for muscle tone and no significant improvements in quality of life were reported at t3., Conclusion: Unassisted fascia training is feasible and safe for patients undergoing alloHCT. This pilot study suggests that fascia training has the potential to improve back flexibility and reduce back pain, and might be a valuable component for physical therapy in patients receiving alloHCT., (© 2022. The Author(s).)
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- 2022
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122. Levitated Micromagnets in Superconducting Traps: A New Platform for Tabletop Fundamental Physics Experiments.
- Author
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Vinante A, Timberlake C, and Ulbricht H
- Abstract
Magnetically levitated microparticles have been proposed as mechanical sensors with extreme sensitivity. In particular, micromagnets levitated above a superconductor can achieve very low levels of dissipation and thermal noise. In this paper, we review recent initial experiments and discuss the potential for using these systems as sensors of magnetic fields and rotational motion, as well as possible applications to fundamental physics.
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- 2022
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123. A way forward for fundamental physics in space.
- Author
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Bassi A, Cacciapuoti L, Capozziello S, Dell'Agnello S, Diamanti E, Giulini D, Iess L, Jetzer P, Joshi SK, Landragin A, Poncin-Lafitte CL, Rasel E, Roura A, Salomon C, and Ulbricht H
- Abstract
Space-based research can provide a major leap forward in the study of key open questions in the fundamental physics domain. They include the validity of Einstein's Equivalence principle, the origin and the nature of dark matter and dark energy, decoherence and collapse models in quantum mechanics, and the physics of quantum many-body systems. Cold-atom sensors and quantum technologies have drastically changed the approach to precision measurements. Atomic clocks and atom interferometers as well as classical and quantum links can be used to measure tiny variations of the space-time metric, elusive accelerations, and faint forces to test our knowledge of the physical laws ruling the Universe. In space, such instruments can benefit from unique conditions that allow improving both their precision and the signal to be measured. In this paper, we discuss the scientific priorities of a space-based research program in fundamental physics., (© 2022. The Author(s).)
- Published
- 2022
- Full Text
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124. Surpassing the Energy Resolution Limit with Ferromagnetic Torque Sensors.
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Vinante A, Timberlake C, Budker D, Kimball DFJ, Sushkov AO, and Ulbricht H
- Abstract
We discuss the fundamental noise limitations of a ferromagnetic torque sensor based on a levitated magnet in the tipping regime. We evaluate the optimal magnetic field resolution taking into account the thermomechanical noise and the mechanical detection noise at the standard quantum limit. We find that the energy resolution limit, pointed out in recent literature as a relevant benchmark for most classes of magnetometers, can be surpassed by many orders of magnitude. Moreover, similarly to the case of a ferromagnetic gyroscope, it is also possible to surpass the standard quantum limit for magnetometry with independent spins, arising from spin-projection noise. Our finding indicates that magnetomechanical systems optimized for magnetometry can achieve a magnetic field resolution per unit volume several orders of magnitude better than any conventional magnetometer. We discuss possible implications, focusing on fundamental physics problems such as the search for exotic interactions beyond the standard model.
- Published
- 2021
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125. Test quantum mechanics in space - invest US$1 billion.
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Belenchia A, Carlesso M, Donadi S, Gasbarri G, Ulbricht H, Bassi A, and Paternostro M
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- 2021
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126. Quantum technologies in space.
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Kaltenbaek R, Acin A, Bacsardi L, Bianco P, Bouyer P, Diamanti E, Marquardt C, Omar Y, Pruneri V, Rasel E, Sang B, Seidel S, Ulbricht H, Ursin R, Villoresi P, van den Bossche M, von Klitzing W, Zbinden H, Paternostro M, and Bassi A
- Abstract
Recently, the European Commission supported by many European countries has announced large investments towards the commercialization of quantum technology (QT) to address and mitigate some of the biggest challenges facing today's digital era - e.g. secure communication and computing power. For more than two decades the QT community has been working on the development of QTs, which promise landmark breakthroughs leading to commercialization in various areas. The ambitious goals of the QT community and expectations of EU authorities cannot be met solely by individual initiatives of single countries, and therefore, require a combined European effort of large and unprecedented dimensions comparable only to the Galileo or Copernicus programs. Strong international competition calls for a coordinated European effort towards the development of QT in and for space, including research and development of technology in the areas of communication and sensing. Here, we aim at summarizing the state of the art in the development of quantum technologies which have an impact in the field of space applications. Our goal is to outline a complete framework for the design, development, implementation, and exploitation of quantum technology in space., (© The Author(s) 2021.)
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- 2021
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127. Detecting Acceleration-Enhanced Vacuum Fluctuations with Atoms Inside a Cavity.
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Lochan K, Ulbricht H, Vinante A, and Goyal SK
- Abstract
Some of the most prominent theoretical predictions of modern times, e.g., the Unruh effect, Hawking radiation, and gravity-assisted particle creation, are supported by from the fact that various quantum constructs like particle content and vacuum fluctuations of a quantum field are observer-dependent. Despite being fundamental in nature, these predictions have not yet been experimentally verified because one needs extremely strong gravity (or acceleration) to bring them within the existing experimental resolution. In this Letter, we demonstrate that a post-Newtonian rotating atom inside a far-detuned cavity experiences strongly modified quantum fluctuations in the inertial vacuum. As a result, the emission rate of an excited atom gets enhanced significantly along with a shift in the emission spectrum due to the change in the quantum correlation under rotation. We propose an optomechanical setup that is capable of realizing such acceleration-induced particle creation with current technology. This provides a novel and potentially feasible experimental proposal for the direct detection of noninertial quantum field theoretic effects.
- Published
- 2020
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128. The Effect of Correction Algorithms on Knee Kinematics and Kinetics during Gait of Patients with Knee Osteoarthritis.
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Ulbricht H, Hou M, Wang X, He J, and Zhang Y
- Abstract
In gait analysis, the accuracy of knee joint angles and moments is critical for clinical decision-making. The purpose of this study was to determine the efficacy of two existing algorithms for knee joint axis correction under pathological conditions. Gait data from 20 healthy participants and 20 patients with knee osteoarthritis (OA) were collected using a motion capture system. An algorithm based on Principal Component Analysis (PCA) and a functional joint-based algorithm (FJA) were used to define the knee joint flexion axis. The results show that PCA decreased crosstalk for both groups, and FJA reduced crosstalk in patients with knee OA only. PCA decreased the range of motions of patients with knee OA in the direction of abduction/adduction significantly. There was a significant increase in the maximum knee flexion moment of patients with knee OA by FJA. The results indicate that both algorithms can efficiently reduce crosstalk for gait from patients with knee OA, which can further influence the results of knee joint angles and moments. We recommend that the correction algorithms be applied in clinical gait analysis with patients with knee OA., Competing Interests: We declare that we have no proprietary, financial, professional, or other personal interest of any nature or kind in any product, service, and/or company that could be construed as influencing the position presented in the manuscript., (Copyright © 2020 Hanna Ulbricht et al.)
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- 2020
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129. Zel'dovich Amplification in a Superconducting Circuit.
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Braidotti MC, Vinante A, Gasbarri G, Faccio D, and Ulbricht H
- Abstract
Zel'dovich proposed that electromagnetic (EM) waves with angular momentum reflected from a rotating metallic, lossy cylinder will be amplified. However, we are still lacking a direct experimental EM-wave verification of this fifty-year-old prediction due to the challenging conditions in which the phenomenon manifests itself: the mechanical rotation frequency of the cylinder must be comparable with the EM oscillation frequency. Here, we propose an experimental approach that solves this issue and is predicted to lead to a measurable Zel'dovich amplification with existing superconducting circuit technology. We design a superconducting circuit with low frequency EM modes that couple through free space to a magnetically levitated and spinning microsphere placed at the center of the circuit. We theoretically estimate the circuit EM mode gain and show that rotation of the microsphere can lead to experimentally observable amplification, thus paving the way for the first EM-field experimental demonstration of Zel'dovich amplification.
- Published
- 2020
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130. Photon Bunching in a Rotating Reference Frame.
- Author
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Restuccia S, Toroš M, Gibson GM, Ulbricht H, Faccio D, and Padgett MJ
- Abstract
Although quantum physics is well understood in inertial reference frames (flat spacetime), a current challenge is the search for experimental evidence of nontrivial or unexpected behavior of quantum systems in noninertial frames. Here, we present a novel test of quantum mechanics in a noninertial reference frame: we consider Hong-Ou-Mandel (HOM) interference on a rotating platform and study the effect of uniform rotation on the distinguishability of the photons. Both theory and experiments show that the rotational motion induces a relative delay in the photon arrival times at the exit beam splitter and that this delay is observed as a shift in the position of the HOM dip. This experiment can be extended to a full general relativistic test of quantum physics using satellites in Earth's orbit and indicates a new route toward the use of photonic technologies for investigating quantum mechanics at the interface with relativity.
- Published
- 2019
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131. Precession Motion in Levitated Optomechanics.
- Author
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Rashid M, Toroš M, Setter A, and Ulbricht H
- Abstract
We investigate experimentally the dynamics of a nonspherical levitated nanoparticle in a vacuum. In addition to translation and rotation motion, we observe the light torque-induced precession and nutation of the trapped particle. We provide a theoretical model, which we numerically simulate and from which we derive approximate expressions for the motional frequencies. Both the simulation and approximate expressions we find in good agreement with experiments. We measure a torque of 1.9±0.5×10^{-23} N m at 1×10^{-1} mbar, with an estimated torque sensitivity of 3.6±1.1×10^{-31} N m/sqrt[Hz] at 1×10^{-7} mbar.
- Published
- 2018
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132. Spin Entanglement Witness for Quantum Gravity.
- Author
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Bose S, Mazumdar A, Morley GW, Ulbricht H, Toroš M, Paternostro M, Geraci AA, Barker PF, Kim MS, and Milburn G
- Abstract
Understanding gravity in the framework of quantum mechanics is one of the great challenges in modern physics. However, the lack of empirical evidence has lead to a debate on whether gravity is a quantum entity. Despite varied proposed probes for quantum gravity, it is fair to say that there are no feasible ideas yet to test its quantum coherent behavior directly in a laboratory experiment. Here, we introduce an idea for such a test based on the principle that two objects cannot be entangled without a quantum mediator. We show that despite the weakness of gravity, the phase evolution induced by the gravitational interaction of two micron size test masses in adjacent matter-wave interferometers can detectably entangle them even when they are placed far apart enough to keep Casimir-Polder forces at bay. We provide a prescription for witnessing this entanglement, which certifies gravity as a quantum coherent mediator, through simple spin correlation measurements.
- Published
- 2017
- Full Text
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133. Experimental Realization of a Thermal Squeezed State of Levitated Optomechanics.
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Rashid M, Tufarelli T, Bateman J, Vovrosh J, Hempston D, Kim MS, and Ulbricht H
- Abstract
We experimentally squeeze the thermal motional state of an optically levitated nanosphere by fast switching between two trapping frequencies. The measured phase-space distribution of the center of mass of our particle shows the typical shape of a squeezed thermal state, from which we infer up to 2.7 dB of squeezing along one motional direction. In these experiments the average thermal occupancy is high and, even after squeezing, the motional state remains in the remit of classical statistical mechanics. Nevertheless, we argue that the manipulation scheme described here could be used to achieve squeezing in the quantum regime if preceded by cooling of the levitated mechanical oscillator. Additionally, a higher degree of squeezing could, in principle, be achieved by repeating the frequency-switching protocol multiple times.
- Published
- 2016
- Full Text
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134. Effects of Newtonian gravitational self-interaction in harmonically trapped quantum systems.
- Author
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Großardt A, Bateman J, Ulbricht H, and Bassi A
- Abstract
The Schrödinger-Newton equation has gained attention in the recent past as a nonlinear modification of the Schrödinger equation due to a gravitational self-interaction. Such a modification is expected from a fundamentally semi-classical theory of gravity and can, therefore, be considered a test case for the necessity of the quantisation of the gravitational field. Here we provide a thorough study of the effects of the Schrödinger-Newton equation for a micron-sized sphere trapped in a harmonic oscillator potential. We discuss both the effect on the energy eigenstates and the dynamical behaviour of squeezed states, covering the experimentally relevant parameter regimes.
- Published
- 2016
- Full Text
- View/download PDF
135. Visualisation of quantum evolution in the Stern-Gerlach and Rabi experiments.
- Author
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Utz M, Levitt MH, Cooper N, and Ulbricht H
- Abstract
The Stern-Gerlach experiment is a seminal experiment in quantum physics, involving the interaction between a particle with spin and an applied magnetic field gradient. A recent article [Wennerström et al., Phys. Chem. Chem. Phys., 2012, 14, 1677-1684] claimed that a full understanding of the Stern-Gerlach experiment can only be attained if transverse spin relaxation is taken into account, generated by fluctuating magnetic fields originating in the magnetic materials which generate the field gradient. This interpretation is contrary to the standard quantum description of the Stern-Gerlach experiment, which requires no dissipative effects. We present simulations of conventional quantum dynamics in the Stern-Gerlach experiment, using extended Wigner functions to describe the propagation of the quantum state in space and time. No relaxation effects are required to reproduce the qualitative experimental behaviour. We also present simulations of quantum dynamics in the Rabi experiment, in which an applied radiofrequency field induces spin transitions in the particle wave.
- Published
- 2015
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136. On the existence of low-mass dark matter and its direct detection.
- Author
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Bateman J, McHardy I, Merle A, Morris TR, and Ulbricht H
- Abstract
Dark Matter (DM) is an elusive form of matter which has been postulated to explain astronomical observations through its gravitational effects on stars and galaxies, gravitational lensing of light around these, and through its imprint on the Cosmic Microwave Background (CMB). This indirect evidence implies that DM accounts for as much as 84.5% of all matter in our Universe, yet it has so far evaded all attempts at direct detection, leaving such confirmation and the consequent discovery of its nature as one of the biggest challenges in modern physics. Here we present a novel form of low-mass DM χ that would have been missed by all experiments so far. While its large interaction strength might at first seem unlikely, neither constraints from particle physics nor cosmological/astronomical observations are sufficient to rule out this type of DM, and it motivates our proposal for direct detection by optomechanics technology which should soon be within reach, namely, through the precise position measurement of a levitated mesoscopic particle which will be perturbed by elastic collisions with χ particles. We show that a recently proposed nanoparticle matter-wave interferometer, originally conceived for tests of the quantum superposition principle, is sensitive to these collisions, too.
- Published
- 2015
- Full Text
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137. A proposal for the experimental detection of CSL induced random walk.
- Author
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Bera S, Motwani B, Singh TP, and Ulbricht H
- Abstract
Continuous Spontaneous Localization (CSL) is one possible explanation for dynamically induced collapse of the wave-function during a quantum measurement. The collapse is mediated by a stochastic non-linear modification of the Schrödinger equation. A consequence of the CSL mechanism is an extremely tiny violation of energy-momentum conservation, which can, in principle, be detected in the laboratory via the random diffusion of a particle induced by the stochastic collapse mechanism. In a paper in 2003, Collett and Pearle investigated the translational CSL diffusion of a sphere, and the rotational CSL diffusion of a disc, and showed that this effect dominates over the ambient environmental noise at low temperatures and extremely low pressures (about ten-thousandth of a pico-Torr). In the present paper, we revisit their analysis and argue that this stringent condition on pressure can be relaxed, and that the CSL effect can be seen at the pressure of about a pico-Torr. A similar analysis is provided for diffusion produced by gravity-induced decoherence, where the effect is typically much weaker than CSL. We also discuss the CSL induced random displacement of a quantum oscillator. Lastly, we propose possible experimental set-ups justifying that CSL diffusion is indeed measurable with the current technology.
- Published
- 2015
- Full Text
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138. Near-field interferometry of a free-falling nanoparticle from a point-like source.
- Author
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Bateman J, Nimmrichter S, Hornberger K, and Ulbricht H
- Abstract
Matter-wave interferometry performed with massive objects elucidates their wave nature and thus tests the quantum superposition principle at large scales. Whereas standard quantum theory places no limit on particle size, alternative, yet untested theories--conceived to explain the apparent quantum to classical transition--forbid macroscopic superpositions. Here we propose an interferometer with a levitated, optically cooled and then free-falling silicon nanoparticle in the mass range of one million atomic mass units, delocalized over >150 nm. The scheme employs the near-field Talbot effect with a single standing-wave laser pulse as a phase grating. Our analysis, which accounts for all relevant sources of decoherence, indicates that this is a viable route towards macroscopic high-mass superpositions using available technology.
- Published
- 2014
- Full Text
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139. Optomechanical interface for probing matter-wave coherence.
- Author
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Xuereb A, Ulbricht H, and Paternostro M
- Abstract
We combine matter-wave interferometry and cavity optomechanics to propose a coherent matter-light interface based on mechanical motion at the quantum level. We demonstrate a mechanism that is able to transfer non-classical features imprinted on the state of a matter-wave system to an optomechanical device, transducing them into distinctive interference fringes. This provides a reliable tool for the inference of quantum coherence in the particle beam. Moreover, we discuss how our system allows for intriguing perspectives, paving the way to the construction of a device for the encoding of quantum information in matter-wave systems. Our proposal, which highlights previously unforeseen possibilities for the synergistic exploitation of these two experimental platforms, is explicitly based on existing technology, available and widely used in current cutting-edge experiments.
- Published
- 2013
- Full Text
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140. Experimental methods of molecular matter-wave optics.
- Author
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Juffmann T, Ulbricht H, and Arndt M
- Subjects
- Interferometry, Motion, Nanoparticles, Optical Phenomena, Quantum Theory, Optics and Photonics methods
- Abstract
We describe the state of the art in preparing, manipulating and detecting coherent molecular matter. We focus on experimental methods for handling the quantum motion of compound systems from diatomic molecules to clusters or biomolecules.Molecular quantum optics offers many challenges and innovative prospects: already the combination of two atoms into one molecule takes several well-established methods from atomic physics, such as for instance laser cooling, to their limits. The enormous internal complexity that arises when hundreds or thousands of atoms are bound in a single organic molecule, cluster or nanocrystal provides a richness that can only be tackled by combining methods from atomic physics, chemistry, cluster physics, nanotechnology and the life sciences.We review various molecular beam sources and their suitability for matter-wave experiments. We discuss numerous molecular detection schemes and give an overview over diffraction and interference experiments that have already been performed with molecules or clusters.Applications of de Broglie studies with composite systems range from fundamental tests of physics up to quantum-enhanced metrology in physical chemistry, biophysics and the surface sciences.Nanoparticle quantum optics is a growing field, which will intrigue researchers still for many years to come. This review can, therefore, only be a snapshot of a very dynamical process.
- Published
- 2013
- Full Text
- View/download PDF
141. Coherent control of the motion of complex molecules and the coupling to internal state dynamics.
- Author
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Venn P and Ulbricht H
- Subjects
- Models, Molecular, Molecular Conformation, Stereoisomerism, Azo Compounds chemistry, Quantum Theory
- Abstract
We discuss coherent control of the centre of mass motion of complex molecules by de Broglie interferometry. We describe an experiment to couple the dynamics of internal state population of complex molecules to their centre of mass motion. We discuss how this can be used to probe state population and transition, especially the photo-switching of flourinated di-azobenzene molecules between their cis- and trans-configuration. We propose an experiment to photo-isomerise complex di-azobenzene molecules in the gas-phase, including the selective detection of molecules in different conformations. In addition we discuss possible ways of optimising the conformation detection through cooling, and optical techiques.
- Published
- 2011
- Full Text
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142. Note: A helical velocity selector for continuous molecular beams.
- Author
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Szewc C, Collier JD, and Ulbricht H
- Abstract
We report on a modern realization of the classic helical velocity selector for gas phase particle beams. The device operates stably under high vacuum conditions at rotational frequencies limited only by commercial dc motor capabilities. Tuning the rotational frequency allows selective scanning over a broad velocity band. The width of the selected velocity distributions at full-width-half-maximum is as narrow as a few percent of the selected mean velocity and independent of the rotational speed of the selector. The selector generates low vibrational noise amplitudes comparable to mechanically damped state-of-the-art turbo-molecular pumps and is therefore compatible with vibration sensitive experiments like molecule interferometry.
- Published
- 2010
- Full Text
- View/download PDF
143. Oral peanut immunotherapy in children with peanut anaphylaxis.
- Author
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Blumchen K, Ulbricht H, Staden U, Dobberstein K, Beschorner J, de Oliveira LC, Shreffler WG, Sampson HA, Niggemann B, Wahn U, and Beyer K
- Subjects
- Administration, Oral, Adolescent, Child, Child, Preschool, Desensitization, Immunologic adverse effects, Double-Blind Method, Female, Humans, Interleukin-4 biosynthesis, Interleukin-5 biosynthesis, Male, Peanut Hypersensitivity immunology, Desensitization, Immunologic methods, Peanut Hypersensitivity therapy
- Abstract
Background: The only treatment option for peanut allergy is strict avoidance., Objective: To investigate efficacy and safety of oral immunotherapy (OIT) in peanut allergy., Methods: Twenty-three children (age, 3.2-14.3 years) with IgE-mediated peanut allergy confirmed by positive double-blind, placebo-controlled food challenge (DBPCFC) received OIT following a rush protocol with roasted peanut for 7 days. If a protective dose of at least 0.5 g peanut was not achieved, patients continued with a long-term buildup protocol using biweekly dose increases up to at least 0.5 g peanut. A maintenance phase for 8 weeks was followed by 2 weeks of peanut avoidance and a final DBPCFC. Immunologic parameters were determined., Results: After OIT using the rush protocol, patients tolerated a median dose of only 0.15 g peanut. Twenty-two of 23 patients continued with the long-term protocol. After a median of 7 months, 14 patients reached the protective dose. At the final DBPCFC, patients tolerated a median of 1 g (range, 0.25-4 g) in comparison with 0.19 g peanut at the DBPCFC before OIT (range, 0.02-1 g). In 2.6% of 6137 total daily doses, mild to moderate side effects were observed; in 1.3%, symptoms of pulmonary obstruction were detected. OIT was discontinued in 4 of 22 patients because of adverse events. There was a significant increase in peanut-specific serum IgG(4) and a decrease in peanut-specific IL-5, IL-4, and IL-2 production by PBMCs after OIT., Conclusion: Long-term OIT appears to be safe and of some benefit in many patients with peanut allergy. With an increase in threshold levels and a reduction of peanut-specific T(H)2 cytokine production, the induction of tolerance may be feasible in some patients., (Copyright 2010 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.)
- Published
- 2010
- Full Text
- View/download PDF
144. Wave and particle in molecular interference lithography.
- Author
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Juffmann T, Truppe S, Geyer P, Major AG, Deachapunya S, Ulbricht H, and Arndt M
- Abstract
The wave-particle duality of massive objects is a cornerstone of quantum physics and a key property of many modern tools such as electron microscopy, neutron diffraction or atom interferometry. Here we report on the first experimental demonstration of quantum interference lithography with complex molecules. Molecular matter-wave interference patterns are deposited onto a reconstructed Si(111) 7x7 surface and imaged using scanning tunneling microscopy. Thereby both the particle and the quantum wave character of the molecules can be visualized in one and the same image. This new approach to nanolithography therefore also represents a sensitive new detection scheme for quantum interference experiments.
- Published
- 2009
- Full Text
- View/download PDF
145. A superconducting NbN detector for neutral nanoparticles.
- Author
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Marksteiner M, Divochiy A, Sclafani M, Haslinger P, Ulbricht H, Korneev A, Semenov A, Gol'tsman G, and Arndt M
- Subjects
- Microscopy, Electron, Scanning, Nanoparticles ultrastructure, Electric Conductivity, Nanoparticles chemistry, Nanotechnology methods, Photons
- Abstract
We present a proof-of-principle study of superconducting single photon detectors (SSPD) for the detection of individual neutral molecules/nanoparticles at low energies. The new detector is applied to characterize a laser desorption source for biomolecules and allows retrieval of the arrival time distribution of a pulsed molecular beam containing the amino acid tryptophan, the polypeptide gramicidin as well as insulin, myoglobin and hemoglobin. We discuss the experimental evidence that the detector is actually sensitive to isolated neutral particles.
- Published
- 2009
- Full Text
- View/download PDF
146. UV and VUV ionization of organic molecules, clusters, and complexes.
- Author
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Marksteiner M, Haslinger P, Sclafani M, Ulbricht H, and Arndt M
- Subjects
- Amino Acids chemistry, Anti-Bacterial Agents chemistry, Gramicidin chemistry, Ions chemistry, Light, Metals chemistry, Molecular Structure, Organometallic Compounds chemistry, Peptides chemistry, Photons, Thermodynamics, Vacuum, Organic Chemicals chemistry, Photochemical Processes, Spectrophotometry, Ultraviolet, Ultraviolet Rays
- Abstract
The generation of organic particle beams is studied in combination with photoionization using UV radiation at 266 nm and vacuum ultraviolet (VUV) light at 157 nm. Single-photon ionization with pulsed VUV light turns out to be sensitive enough to detect various large neutral biomolecular complexes ranging from metal-amino acid complexes to nucleotide clusters and aggregates of polypeptides. Different biomolecular clusters are shown to exhibit rather specific binding characteristics with regard to the various metals that are codesorbed in the source. We also find that the ion signal of gramicidin can be increased by a factor of 15 when the photon energy is increased from 4.66 to 7.9 eV.
- Published
- 2009
- Full Text
- View/download PDF
147. In situ non-invasive investigation on the painting techniques of early Meissen Stoneware.
- Author
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Miliani C, Doherty B, Daveri A, Loesch A, Ulbricht H, Brunetti BG, and Sgamellotti A
- Subjects
- Iron analysis, Lead analysis, Manganese analysis, Multivariate Analysis, Coloring Agents analysis, Oxalates analysis, Paint analysis, Spectrometry, X-Ray Emission methods, Spectroscopy, Fourier Transform Infrared methods
- Abstract
In situ, non-invasive investigations by means of portable X-ray fluorescence and fibre optic reflectance mid-infrared (mid-FTIR) spectroscopy of painted Böttger Stoneware objects have been carried out through the MOLAB transnational access to the Porcelain Collection of the Staatliche Kunstsammlungen in Dresden. It has been possible to gather information regarding the composition of the black glaze by applying a principal component analysis to the elemental analysis to distinguish between the variations of lead, iron and manganese compositions of each glaze. It has been furthermore feasible to combine molecular spectroscopy for characterization of the constituent painting materials, namely lead white as cerusite and hydrocerusite, the use of cinnabar, azurite and Prussian blue leading to a better knowledge of the state of conservation and utility of certain pigments that may give rise to chronology of the decorative artwork. The identification of oxalates namely whedellite and moolooite are assigned as degradation products relative to the decorative areas.
- Published
- 2009
- Full Text
- View/download PDF
148. Rush oral immunotherapy in children with persistent cow's milk allergy.
- Author
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Staden U, Blumchen K, Blankenstein N, Dannenberg N, Ulbricht H, Dobberstein K, Ziegert M, Niggemann B, Wahn U, and Beyer K
- Subjects
- Administration, Oral, Adolescent, Animals, Child, Child, Preschool, Desensitization, Immunologic adverse effects, Female, Humans, Male, Milk Hypersensitivity immunology, Desensitization, Immunologic methods, Milk Hypersensitivity therapy
- Published
- 2008
- Full Text
- View/download PDF
149. Gas-phase formation of large neutral alkaline-earth metal tryptophan complexes.
- Author
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Marksteiner M, Haslinger P, Ulbricht H, Sclafani M, Oberhofer H, Dellago C, and Arndt M
- Abstract
We report on the first observation of isolated large neutral metal amino acid complexes such as Trp(n)Me(k), with Me=Ca, Ba, Sr, cluster combinations covering n=1...33, k=0..2 and masses beyond 6500 u. The cluster beam is generated using UV laser desorption from a mixed powder of alkaline-earth metal salts and tryptophan inside a cluster mixing channel. The particles are detected using VUV photoionization followed by time-of-flight mass spectroscopy. The enhanced stability of metal amino acid clusters over pure amino acid clusters is substantiated in molecular dynamics simulations by determining the gain in binding energy related to the inclusion of the metal atoms.
- Published
- 2008
- Full Text
- View/download PDF
150. Gas phase sorting of fullerenes, polypeptides and carbon nanotubes.
- Author
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Ulbricht H, Berninger M, Deachapunya S, Stefanov A, and Arndt M
- Abstract
We discuss the Stark deflectometry of micro-modulated molecular beams for the enrichment of biomolecular isomers as well as single-wall carbon nanotubes, and we demonstrate the working principle of this idea with fullerenes. The sorting is based on the species-dependent susceptibility-to-mass ratio χ/m. The device is compatible with a high molecular throughput, and the spatial micro-modulation of the beam permits one to obtain a fine spatial resolution and a high sorting sensitivity.
- Published
- 2008
- Full Text
- View/download PDF
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