Negative / Null Result ReportOpen accessPhysics
N. Mahfouz, J. Mülmenstädt, S. Burrows · 2024 · Atmospheric Chemistry and Physics
Cloud albedo susceptibility to droplet number perturbation remains a source of uncertainty in understanding aerosol–cloud interactions and thus both past and present climate states. Through the Energy Exascale Earth System Model (E3SM) v2 experiments, we probe the effects of competing processes on cloud albedo susceptibility of low-lying marine stratocumulus in the northeast Pacific. In present-day conditions, we find that increasing precipitation suppression by aerosols increases cloud albedo susceptibility, whereas increasing cloud sedimentation decreases it. By constructing a hypothetical m
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Martin Tajmar, Lance L. Williams · 2020 · Physics
Kaluza was the first to realize that the four-dimensional gravitational field of general relativity and the classical electromagnetic field behave as if they were components of a five-dimensional gravitational field. We present a novel experimental test of the macroscopic classical interpretation of the Kaluza fifth dimension. Our experiment design probes a key feature of Kaluza unification—that electric charge is identified with motion in the fifth dimension. Therefore, we tested for a time dilation effect on an electrically charged clock. This test can also be understood as a constraint on t
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Zihao Qiu, Siyu Chen, Zixin Feng et al. · 2025 · Frontiers in Physics
Futures, as significant financial derivatives, play a crucial role in financial markets by fulfilling price discovery functions and providing efficient risk hedging tools. Against the backdrop of geopolitical conflicts, market risk emerges not only from external shocks and random fluctuations but also from strategic interactions among diverse participants including hedgers, speculators, arbitrageurs, and regulators. This study integrates traditional VaR theory with machine learning methods to systematically examine risk characteristics and transmission mechanisms in the sugar futures market un
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I. Andriana, D. Riyanto, D. Darmawan · 2019 · IOP Conference Series: Materials Science and Engineering
The research purpose was to measure the relationship of workload and motivation to employee’s performance and the effect of motivation on employee’s performance, workload on employee’s performance, workload and motivation on employee’s…
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Yoav Simhon, Alex Segal, Ofer Amrani et al. · 2025 · arXiv
Scintillator-SiPM Particle Detectors (SSPDs) are compact, low-power devices with applications including particle physics, underground tomography, cosmic-ray studies, and space instrumentation. They are based on a prism-shaped scintillator with corner-mounted SiPMs. Previous work has demonstrated that analytic algorithms based on a physical model of light propagation can reconstruct particle impinging positions and tracks and estimate deposited energy and Linear Energy Transfer (LET) with moderate accuracy. In this study, we enhance this approach by applying machine learning (ML) methods, speci
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Krzysztof Pachucki · 2006 · arXiv
Corrections of order $α^4$Ry are calculated for the singlet states $1^1S_0$ and $2^1S_0$ of the helium atom. The result for $1^1S_0$ state is in slight disagreement with that of Korobov and Yelkhovsky in [Phys. Rev. Lett. {\bf 87}, 193003 (2001)]. The results obtained lead to a significant improvement of transition frequencies between low lying levels of the helium atom. In particular theoretical predictions for the $2^1S_0 - 1^1S_0$ transition are found to be in disagreement with experimental values.
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Ingvild Dalehaug, Kirsten Nygaard Bolstad, Daniel Aadnevik et al. · 2017 · arXiv
Purpose: Siemens has developed several iterative reconstruction (IR) algorithms on their CT scanners. SAFIRE is available on most of their CT scanners. The latest algorithm, ADMIRE, is available on their newest high-end CT scanners. The aim of our study was to compare the noise reduction properties of the two IR algorithms using objective methods. Methods and Materials: The homogeneous module of the Catphan phantom was scanned on a Siemens AS+ and a Siemens Flash CT scanner using an axial abdomen protocol with fixed tube current at two dose levels. The images were reconstructed with an abdomen
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Motonari Tonegawa, Tomonori Totani, Masayuki Akiyama et al. · 2013 · arXiv
The efficient selection of high-redshift emission galaxies is important for future large galaxy redshift surveys for cosmology. Here we describe the target selection methods for the FastSound project, a redshift survey for H alpha emitting galaxies at z=1.2-1.5 using Subaru/FMOS to measure the linear growth rate fσ8 via Redshift Space Distortion (RSD) and constrain the theory of gravity. To select ~400 target galaxies in the 0.2 deg^2 FMOS field-of-view from photometric data of CFHTLS-Wide (u*g'r'i'z'), we test several different methods based on color-color diagrams or photometric redshift est
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A. D. Kulkarni, R. M. Shannon, D. J. Reardon et al. · 2024 · arXiv
Pulse-to-pulse profile shape variations introduce correlations in pulsar times of arrival (TOAs) across radio frequency measured at the same observational epoch. This leads to a broadband noise in excess of radiometer noise, which is termed pulse jitter noise. The presence of jitter noise limits the achievable timing precision and decreases the sensitivity of pulsar-timing data sets to signals of interest such as nanohertz-frequency gravitational waves. Current white noise models used in pulsar timing analyses attempt to account for this, assuming complete correlation of uncertainties through
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Dominic M. Bowman, Daniel L. Holdsworth · 2019 · arXiv
Context. Modern space telescopes are currently providing high-precision light curves for a large fraction of the sky, such that many new variable stars are being discovered. However, some stars have periodic variability with periods of order minutes and require high-cadence photometry to probe the physical mechanisms responsible. A cadence of less than a minute is often required to remove Nyquist ambiguities and confirm rapid variability which forces observers to obtain high-cadence ground-based photometry. Aims. We aim to provide a modern software package to reduce ground-based photometric ti
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Sarbani Basu, H. M. Antia · 1999 · arXiv
Ring diagram analysis can be used to study large scale velocity fields in the outer part of the solar convection zone. All previous works assume that the peak profiles in the solar oscillation power spectrum are symmetric. However, it has now been demonstrated that the peaks are not symmetric. In this work we study how the explicit use of asymmetric peak profiles in ring-diagram analysis influences the estimated velocity fields. We find that the use of asymmetric profiles leads to significant improvement in the fits, but the estimated velocity fields are not substantially different from those
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Xian-Yu Wang, Yong-Hao Wang, Songhu Wang et al. · 2021 · arXiv
We present 127 new transit light curves for 39 hot Jupiter systems, obtained over the span of five years by two ground-based telescopes. A homogeneous analysis of these newly collected light curves together with archived spectroscopic, photometric, and Doppler velocimetric data using EXOFASTv2 leads to a significant improvement in the physical and orbital parameters of each system. All of our stellar radii are constrained to accuracies of better than 3\%. The planetary radii for 37 of our 39 targets are determined to accuracies of better than $5\%$. Compared to our results, the literature ecce
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Md Mamun Al-Rashid, Jayasimha Atulasimha, Supriyo Bandyopadhyay · 2014 · arXiv
Strain-clocked dipole-coupled nanomagnetic logic is an energy-efficient Boolean logic paradigm whose progress has been stymied by its propensity for high error rates. In an effort to mitigate this problem, we have studied the effect of nanomagnet geometry on error rates, focusing on elliptical and cylindrical geometries. We had previously reported that the out-of-plane excursion of the magnetization vector during switching creates a precessional torque that is responsible for high switching error probability in elliptical nanomagnet geometries. The absence of this torque in cylindrical magnets
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Mohamed M. Fadlallah, Ulrich Eckern · 2017 · arXiv
The structural, electronic, and optical properties of metal (Si, Ge, Sn, and Pb) mono- and co-doped anatase TiO$_{2}$ nanotubes are investigated, in order to elucidate their potential for photocatalytic applications. It is found that Si doped TiO$_{2}$ nanotubes are more stable than those doped with Ge, Sn, or Pb. All dopants lower the band gap, except the (Ge, Sn) co-doped structure, the decrease depending on the concentration and the type of dopant. Correspondingly, a redshift in the optical properties for all kinds of dopings is obtained. Even though a Pb mono- and co-doped TiO$_{2}$ nanotu
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Chris Pankow, Laura Sampson, Leah Perri et al. · 2016 · arXiv
The detection of electromagnetic counterparts to gravitational waves has great promise for the investigation of many scientific questions. It has long been hoped that in addition to providing extra, non-gravitational information about the sources of these signals, the detection of an electromagnetic signal in conjunction with a gravitational wave could aid in the analysis of the gravitational signal itself. That is, knowledge of the sky location, inclination, and redshift of a binary could break degeneracies between these extrinsic, coordinate-dependent parameters and the physical parameters,
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Sergei Manzhos, Pavlo Golub · 2020 · arXiv
We study the dependence of kinetic energy densities (KED) on density-dependent variables that have been suggested in previous works on kinetic energy functionals (KEF) for orbital-free DFT (OF-DFT). We focus on the role of data distribution and on data and regressor selection. We compare unweighted and weighted linear and Gaussian process regressions of KED for light metals and a semiconductor. We find that good quality linear regression resulting in good energy-volume dependence is possible over density-dependent variables suggested in previous literature. This is achieved with weighted fitti
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Florian Sammüller, Sophie Hermann, Matthias Schmidt · 2022 · arXiv
We reexamine results obtained with the recently proposed density functional theory framework based on forces (force-DFT) [Tschopp et al., Phys. Rev. E 106, 014115 (2022)]. We compare inhomogeneous density profiles for hard sphere fluids to results from both standard density functional theory and from computer simulations. Test situations include the equilibrium hard sphere fluid adsorbed against a planar hard wall and the dynamical relaxation of hard spheres in a switched harmonic potential. The comparison to grand canonical Monte Carlo simulation profiles shows that equilibrium force-DFT alon
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Jaroslaw Zdebik · 2008 · arXiv
The work was carried out in the framework of the KLOE collaboration studying the decays of the phi meson produced in the DAFNE accelerator in the collisions of electron and positron. The main aim of this thesis was investigation of the influence of the merging and splitting of clusters in decays with the high multiplicity of gamma quanta, which are at most biased by these effects. For this aim we implemented the full geometry and realistic material composition of the barrel electromagnetic calorimeter in FLUKA package. The prepared Monte Carlo based simulation program permits to achieve a fast
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Laura Stricker, Benjamin Dollet, David Fernandez Rivas et al. · 2013 · arXiv
Acoustically driven air pockets trapped in artificial crevices on a sur- face can emit bubbles which organize in (interacting) bubble clusters. With increasing driving power Fernandez Rivas et al. [Angew. Chem. Int. Ed., 2010] observed three different behaviors: clusters close to the very pits out of which they had been created, clusters pointing toward each other, and merging clusters. The latter behavior is highly undesired for technological purposes as it is associated with a reduction of the radical production and an enhancement of the erosion of the reactor walls. The dependence on the co
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Atsushi Taruya, Takahiro Nishimichi, Donghui Jeong · 2021 · arXiv
Perturbation theory (PT) has been used to interpret the observed nonlinear large-scale structure statistics at the quasi-linear regime. To facilitate the PT-based analysis, we have presented the GridSPT algorithm, a grid-based method to compute the nonlinear density and velocity fields in standard perturbation theory (SPT) from a given linear power spectrum. Here, we further put forward the approach by taking the redshift-space distortions into account. With the new implementation, we have, for the first time, generated the redshift-space density field to the fifth order and computed the next-
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Fabien Robineau, Frédéric Boy, Jean-Pierre Orliaguet et al. · 2006 · arXiv
Performing minimal-invasive surgical punctures require guiding a needle toward an intracorporeal clinically-defined target. As this technique does not involve cutting the body open, a visualization system is employed to provide the surgeon with indirect visual spatial information about the intracorporeal positions of the tool. One may consider that such systems reduce the ergonomics of the situation as they generate a decorrelation between the actual movement of the needle and the displayed information about this movement. The present study aims at assessing the guidance of an intracorporeal p
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Nataša Pavlov, Ana Mitrašinović · 2025 · arXiv
The recent discovery of the most extended ultra-diffuse galaxy (UDG), Nube, has raised yet another question about the validity of the cold dark matter (CDM) model. The studies using cosmological and zoom-in simulations, which assume CDM, failed to replicate galaxies with the structural properties of Nube. However, the simulation box or the examined population of UDGs may be too narrow to fully capture the range of effects that can lead to the formation of such extraordinary galaxies. In this work we present a case study of a Nube-like galaxy from TNG100, the most extended simulated UDG examine
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Agnès Ferté, Kevin Hong · 2023 · arXiv
We highlight the role of weak lensing measurements from current and upcoming stage-IV imaging surveys in the search for cosmic inflation, specifically in measuring the scalar spectral index $n_s$. To do so, we combine the Dark Energy Survey 3 years of observation weak lensing and clustering data with BICEP/Keck, Planck and Sloan Digital Sky Survey data in $rΛ$CDM where $r$ is the tensor-to-scalar ratio. While there is no significant improvement in constraining power, we obtain a 1$σ$ shift on $n_s$. Additionally, we forecast a weak lensing and clustering data vector from the 10-year Legacy Sur
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F. M. Brunbauer, R. Aleksan, Y. Angelis et al. · 2026 · arXiv
The combination of a Cherenkov radiator with a semi-transparent photocathode and a Micromegas based amplification stage allows PICOSEC Micromegas detectors to achieve a time resolution of better than 15ps. While tileable prototypes with 10x10 channels feature 1x1 cm^2 readout pads, finer readout granularity can be used to improve the spatial resolution. We report on the study of high readout granularity PICOSEC Micromegas prototypes which achieve around 0.5mm spatial resolution with 3.5mm large pads. No significant improvement was found when readout pad size was further reduced to 2.2mm. The t
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Filip K. Malinowski, Frederico Martins, Peter D. Nissen et al. · 2017 · arXiv
We operate a resonant exchange qubit in a highly symmetric triple-dot configuration using IQ-modulated RF pulses. At the resulting three-dimensional sweet spot the qubit splitting is an order of magnitude less sensitive to all relevant control voltages, compared to the conventional operating point, but we observe no significant improvement in the quality of Rabi oscillations. For weak driving this is consistent with Overhauser field fluctuations modulating the qubit splitting. For strong driving we infer that effective voltage noise modulates the coupling strength between RF drive and the qubi
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Guoliang Shang, Lukas Maiwald, Hagen Renner et al. · 2018 · arXiv
Non-iridescent structural colors based on disordered arrangement of monodisperse spherical particles, also called photonic glass, show low color saturation due to gradual transition in reflectivity. No significant improvement is usually expected from particles optimization, as the Mie resonances are broad for small dielectric particles with moderate refractive index. Moreover, the short range order of a photonic glass alone is also insufficient to cause sharp spectral features. We show here, that the combination of a well-chosen particle geometry with the short range order of a photonic glass
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Mykola Malygin, Dmytro Iakubovskyi · 2010 · arXiv
In this work, we perform the detailed analysis of absorption features in spectra of magnetar candidates observed by XMM-Newton satellite. No significant line-like feature has been found. This negative result may indicate the possible presence of smoothing out the absorption features mechanisms.
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Brandon W. Langley, Garrett Vanacore, Philip W. Phillips · 2015 · arXiv
We compute conductivities of strongly-interacting and non-uniform charge densities dual to inhomogeneous anti-de Sitter--black hole spacetimes. Backreacting bulk scalars with periodic boundary profiles, we construct generalizations of Reissner-Nordström-AdS that interpolate between those used in two previous studies --- one that reports power-law scaling for the boundary optical conductivity and one that does not. We find no evidence for power-law scaling of the conductivity, thereby corroborating the previous negative result that gravitational crystals are insufficient to generate the power-l
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R. Foot · 2004 · arXiv
We examine the recent CDMS II results in the context of the mirror matter interpretation of the DAMA/NaI experiment.We find that the favoured mirror matter interpretation of the DAMA/NaI experiment -- a $He'/H'$ dominated halo with a small $O'$ component is fully consistent with the null results reported by CDMS II. While the CDMS II experiment is quite sensitive to a heavy $Fe'$ component, and may yet find a positive result, a more decisive test of mirror matter-type dark matter would require a lower threshold experiment using light target elements.
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Cheongho Han · 1994 · arXiv
Spin vectors of 60 galaxies in the ``Ursa Major Filament'' are obtained from CCD images and spectroscopic determinations of the directions of rotation. These data are used to remove the four-fold degeneracy introduced by the project ed images of galaxies, making possible the complete reconstruction of the galaxy spin vectors. Several possible organizations of spin vectors are investigated by means of statistical analyses of the three-dimensional spin vector maps. The results indicate that there exists no significant alignment of galaxy spin vectors with respect to the supergalactic plane, the
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