Oscillation Measurements Research Articles

Dark energy at early times and ACT data: A larger Hubble constant without late-time priors

In this paper we fit two models of Early Dark Energy (EDE) (an increase in the expansion rate before recombination) to the combination of Atacama Cosmology Telescope (ACT) measurements of the Cosmic Microwave Background (CMB) with data from either the WMAP or the Planck satellite, along with measurements of the baryon acoustic oscillations and uncalibrated supernovae luminosity distance. We study a phenomenological axion-like potential ('axEDE') and a scalar field experiencing a first-order phase-transition ('NEDE'). We find that for both models the 'Planck-free' analysis yields non-zero EDE at > 2 sigma and an increased value for $H_0 \sim 70-74$ km/s/Mpc, compatible with local measurements, without the inclusion of any prior on $H_0$. On the other hand, the inclusion of Planck data restricts the EDE contribution to an upper-limit only at 95% C.L. For axEDE, the combination of Planck and ACT leads to constraints 30% weaker than with Planck alone, and there is no residual Hubble tension. On the other hand, NEDE is more strongly constrained in a Planck+ACT analysis, and the Hubble tension remains at $\sim 3\sigma$, illustrating the ability for CMB data to distinguish between EDE models. We explore the apparent inconsistency between the Planck and ACT data and find that it comes (mostly) from a slight tension between the temperature power spectrum at multipoles around $\sim 1000$ and $\sim 1500$. Finally, through a mock analysis of ACT data, we demonstrate that the preference for EDE is not driven by a lack of information at high-$\ell$ when removing Planck data, and that a LCDM fit to the fiducial EDE cosmology results in a significant bias on $\{H_0,\omega_{\rm cdm}\}$. More accurate measurements of the TT power spectra above $\ell\sim 2500$ and EE between $\ell \sim 300-500$ will play a crucial role in differentiating EDE models.

Relationships among pulmonary function, anxiety and depression in mild asthma: An exploratory study

In a secondary analysis of data from a prior study, we calculated the relationships among depression (PHQ-8), anxiety (GAD-7), and measures of asthma in 69 steroid-naïve patients with mild and moderate symptomatic asthma. Average levels of pulmonary function, depression and anxiety tended to be in the normal range, and asthma tended to be well controlled (Asthma Control Test). Nevertheless, PHQ-8 scores were significantly correlated with forced oscillation (FO) measures of airway reactance (AX) and resistance at a low frequency of stimulation (Rrs5 Hz). GAD-7 scores also were significantly related to Rrs5 Hz. Exploratory analyses in Supplementary data provide no evidence for vagal mediation of the association. Further research is necessary to discover mechanisms for the associations found here. Future studies might examine the utility of assessing and treating mild anxiety and depression in mild to moderate asthma.

An Oscillator without Linear Terms: Infinite Equilibria, Chaos, Realization, and Application

Oscillations and oscillators appear in various fields and find applications in numerous areas. We present an oscillator with infinite equilibria in this work. The oscillator includes only nonlinear elements (quadratic, absolute, and cubic ones). It is different from common oscillators, in which there are linear elements. Special features of the oscillator are suitable for secure applications. The oscillator’s dynamics have been discovered via simulations and an electronic circuit. Chaotic attractors, bifurcation diagrams, Lyapunov exponents, and the boosting feature are presented while measurements of the implemented oscillator are reported by using an oscilloscope. We introduce a random number generator using such an oscillator, which is applied in biomedical image encryption. Moreover, the security and performance analysis are considered to confirm the correctness of encryption and decryption processes.

Detecting attention-related rhythms: When is behavior not enough? (Commentary on van der Werf et al. 2021).

Recent research suggests that environmental sampling is a fundamentally rhythmic process (Benedetto, Morrone, & Tomassini, 2019; Fiebelkorn & Kastner, 2019; Schroeder, Wilson, Radman, Scharfman, & Lakatos, 2010). In primates, both attention-related sampling and exploratory eye movements are seemingly shaped by theta-band activity (3-8 Hz) in the large-scale network that directs both spatial attention and goal-directed eye movements (i.e., the 'attention network').

Fermi Surface Structure and Isotropic Stability of Fulde-Ferrell-Larkin-Ovchinnikov Phase in Layered Organic Superconductor β″-(BEDT-TTF)2SF5CH2CF2SO3

The Fermi surface structure of a layered organic superconductor β″-(BEDT-TTF)2SF5CH2CF2SO3 was determined by angular-dependent magnetoresistance oscillations measurements and band-structure calculations. This salt was found to have two small pockets with the same area: a deformed square hole pocket and an elliptic electron pocket. Characteristic corrugations in the field dependence of the interlayer resistance in the superconducting phase were observed at any in-plane field directions. The features were ascribed to the commensurability (CM) effect between the Josephson vortex lattice and the periodic nodal structure of the superconducting gap in the Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) phase. The CM effect was observed in a similar field region for various in-plane field directions, in spite of the anisotropic nature of the Fermi surface. The results clearly showed that the FFLO phase stability is insensitive to the in-plane field directions.

High-frequency transverse combustion instabilities of lean-premixed multislit hydrogen-air flames

The present experimental investigation is concerned with combustion dynamics of lean-premixed multislit hydrogen-air flames, with the aim of addressing some of the central technical problems associated with the development of low-emission carbon-free gas turbine combustion technology. To mitigate flashback risk in relatively fast premixed hydrogen flames, we use a multislit injector assembly with a slit width of 1.5 mm, of the same order of magnitude as the characteristic thickness of lean-premixed hydrogen flames. This new perspective on the characteristic nozzle dimension makes it possible to scrutinize the dynamics of multisheet hydrogen flames under extreme conditions. We carry out extensive measurements of self-excited pressure oscillations over a broad range of operating conditions between 30 and 100 kW thermal power. The experimental datasets are analyzed using the acoustic wave decomposition method, low-order thermoacoustic network modeling, and FEM-based three-dimensional Helmholtz simulations. We show that lean-premixed multislit hydrogen flames – unlike the multi-element hydrogen-air flame ensembles considered in our earlier investigations – undergo strong high-frequency pressure oscillations between 3.1 and 3.5 kHz in excess of 25 kPa, originating from the triggering of the first tangential mode of the combustion chamber. Whereas the frequency of the first tangential mode is well defined by the square root dependence of adiabatic flame temperature, the magnitude of pressure fluctuations is observed to be intensified exponentially with increasing flame temperature up to 2200 K. We demonstrate that the transverse mode is characterized by high-amplitude spinning modes in the clockwise direction under relatively short combustor length conditions, discontinuously switching to counter-clockwise spinning modes at relatively long combustor length, and eventually transitioning to a moderate standing wave mode at the same resonant frequency. These observations demonstrate the previously unidentified complex modal dynamics induced by lean-premixed multislit hydrogen-air flames of nozzle dimension comparable to the characteristic length scale of the flame.

T2K latest results on neutrino-nucleus cross sections

Neutrino interaction cross section measurements are of high importance, in improving understanding for both oscillation measurements and nuclear modelling. The T2K experiment features a near detector complex with multiple detectors, providing multiple different nuclear targets at differing mean neutrino energies due to the off-axis configurations used. Along with constraining the flux for oscillation measurements, these near detectors provide the opportunity for a large programme of neutrino cross section measurements. Some recent such measurements are described in this proceeding.

Evaluation of event reconstruction with small-scale water Cherenkov detectors

The Hyper-Kamiokande experiment is planned to start in 2027 aiming for precise measurement of neutrino oscillation using J-PARC neutrino beam including the search for CP violation in the lepton sector. The Hyper-Kamiokande detector is a 260 kiloton water Cherenkov detector. In order to achieve the precision measurement, systematic uncertainties should be suppressed. For this purpose, a new 1 kiloton scale Intermediate Water Cherenkov Detector (IWCD) is proposed to measure the neutrino flux and interaction cross section near the generation point of the neutrino beam before oscillation. Water Cherenkov Test Experiment (WCTE) is a 50 ton scale water Cherenkov detector and currently under preparation to validate the performance of IWCD. WCTE will use new photosensor called multi-PMT and study the response of small water Cherenkov detectors to electron, muon, and hadron beams at CERN. The performance of event reconstruction with the IWCD and WCTE detectors is evaluated using simulation.

Dark Energy Survey Year 3 Results: Galaxy mock catalogs for BAO analysis

The calibration and validation of scientific analysis in simulations is a fundamental tool to ensure unbiased and robust results in observational cosmology. In particular, mock galaxy catalogs are a crucial resource to achieve these goals in the measurement of baryon acoustic oscillation (BAO) in the clustering of galaxies. Here we present a set of 1952 galaxy mock catalogs designed to mimic the Dark Energy Survey Year 3 BAO sample over its full photometric redshift range 0.6 < zphoto < 1.1. The mocks are based upon 488 ICE-COLA fastN-body simulations of full-sky light cones and were created by populating halos with galaxies, using a hybrid halo occupation distribution – halo abundance matching model. This model has ten free parameters, which were determined, for the first time, using an automatic likelihood minimization procedure. We also introduced a novel technique to assign photometric redshift for simulated galaxies, following a two-dimensional probability distribution with VIMOS Public Extragalactic Redshift Survey data. The calibration was designed to match the observed abundance of galaxies as a function of photometric redshift, the distribution of photometric redshift errors, and the clustering amplitude on scales smaller than those used for BAO measurements. An exhaustive analysis was done to ensure that the mocks reproduce the input properties. Finally, mocks were tested by comparing the angular correlation functionw(θ), angular power spectrumCℓ, and projected clusteringξp(r⊥) to theoretical predictions and data. The impact of volume replication in the estimate of the covariance is also investigated. The success in accurately reproducing the photometric redshift uncertainties and the galaxy clustering as a function of redshift render this mock creation pipeline as a benchmark for future analyses of photometric galaxy surveys.

Technology Focus: Bits and Bottomhole Assemblies (December 2021)

Well construction must always be executed safely at reduced operational costs, while ensuring appropriate wellbore quality and placement, per asset team requirements. Consequently, analysis of drilling efficiency, a critical performance indicator, has moved from maximizing rate of penetration (ROP) to improving cycle time. This recognition establishes the need for holistic solutions that address drilling challenges and promote efficient improvement strategies. This endeavor achieves well construction objectives, with associated reductions in cycle time and operations costs. Holistic solutions must start with project analysis and comparisons to offsets to identify application differences and similarities. These evaluations establish project risks, which ultimately have positive or negative effects on well construction. Consequently, implications from these risks (limiters and potential dysfunctions) must be addressed in the planning phase, or preparations must be made for their remediation during project execution. It is not enough to know what worked or failed. Rather, it is essential to understand why and how specific trends, events, results, or relationships come about. Effective and permanent remediations for all drilling dysfunctions must focus on identification and analysis of their initiating risks. Additionally, holistic solutions require detailed analysis of drilling systems, which include bits and reamers, bottomhole assemblies (BHAs), drive systems, hydraulics considerations, and drilling-parameter ranges and roadmaps. In addition to establishing component relevance, this effort must ensure their functional compatibility and effectiveness at addressing project risks. Drilling-parameter roadmaps must focus on well construction objectives and cycle time reduction, not ROP maximization. In this regard, cycle time is defined as the cumulative time associated with the following operations: pick up the BHA, drill out, drill ahead, trip out of hole, and run casing. Bits and BHAs have a major role in this discussion. The industry’s fast-developing capabilities with modeling and deeper under-standing of downhole tools and systems, coupled with applications based on big data analytics, are leading these efforts. The door has been kicked open. Let’s walk through. Recommended additional reading at OnePetro: www.onepetro.org. SPE 205965 - Oil and Gas Drilling Optimization Technologies Applied Successfully to Unconventional Geothermal Well Drilling by Junichi Sugiura, Sanvean Technologies, et al. SPE 205993 - Using Downhole Sampled High-Frequency Torsional Oscillation Measurements for Identifying Stringers and Minimizing Operational Invisible Lost Time by Andreas Hohl, Baker Hughes, et al. SPE 206064 - Mud Motor PDM Dynamics: An Analytical Model by Robello Samuel, Halliburton, et al.

Time Projection Chambers instrumented with resistive MicroMegas for the SAND near detector of DUNE

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino accelerator experiment aiming for precise measurements of the neutrino oscillation parameters. DUNE will include a near detector complex regrouping three different detectors among which SAND (System for on-Axis Neutrino Detection) that will be the only one permanently on the neutrino beam axis in charge of monitoring in detail the emitted neutrino beam and its stability through time, a crucial characteristic to realize accurate oscillation measurements at the percent level. SAND will reuse the superconducting magnet and the electromagnetic calorimeter of the KLOE experiment. We will describe in the following the proposal of using, as inner tracker of SAND, a large 3D matrix of 1.5cm side scintillator cubes (3DST) surrounded by 3 gaseous Time Projection Chambers. This setup allows to realize accurate beam monitoring combining the 3DST unprecedented capability of neutron detection and energy measurement with the high precision momentum resolution for charged particles offered by the TPCs. The proposed TPC design allows to reach spatial resolutions of a few hundreds of micrometers using 1 cm pads by deploying the resistive MicroMegas technology for the charge readout.

Physics with NOvA: a half-time review

The NOvA experiment has been collecting data in the NuMI neutrino beam since 2014. In this article we describe the rich physics program of the experiment, including long-baseline oscillation measurements, neutrino cross-section measurements, searches for phenomena beyond the standard three flavor oscillation paradigm, as well as astrophysical searches. Only half way through its expected run plan, NOvA will continue to explore exciting physics topics through 2026 and beyond.

Complexity measures of high oscillations in phonocardiogram as biomarkers to distinguish between normal heart sound and pathological murmur

In this study, we present an improved computer-aided-diagnosis (CAD) system to distinguish between normal heart sound and one affected with murmur. The proposed system is based on nonlinear characteristics of the original heart sound high frequency oscillations. Specifically, the original signal is decomposed by discrete wavelet transform (DWT) and analyzed by complexity measures in a straightforward manner to describe its overall characteristics, rather than to describe characteristics of the sounds related to the turbulent flow during the different phases of a heartbeat. The complexity measures include Hurst exponent, Lempel-Ziv information, and Shannon entropy. They are computed from the high frequency oscillations which are obtained by wavelet transform. These nonlinear characteristics are employed to train nonlinear support vector machines (SVM) classifier. The latter was tuned by Bayesian optimization. Tested on a new large dataset, the proposed CAD system outperforms existing models that were validated on the same database. The proposed approach is fast, effective, and promising in clinical milieu.

All are aromatic: A 3D globally aromatic cage containing five types of 2D aromatic macrocycles

All are aromatic: A 3D globally aromatic cage containing five types of 2D aromatic macrocycles

Electron-beam energy reconstruction for neutrino oscillation measurements.

Neutrinos exist in one of three types or 'flavours'-electron, muon and tau neutrinos-and oscillate from one flavour to another when propagating through space. This phenomena is one of the few that cannot be described using the standard model of particle physics (reviewed in ref. 1), and so its experimental study can provide new insight into the nature of our Universe (reviewed in ref. 2). Neutrinos oscillate as a function of their propagation distance (L) divided by their energy (E). Therefore, experiments extract oscillation parameters by measuring their energy distribution at different locations. As accelerator-based oscillation experiments cannot directly measure E, the interpretation of these experiments relies heavily on phenomenological models of neutrino-nucleus interactions to infer E. Here we exploit the similarity of electron-nucleus and neutrino-nucleus interactions, and use electron scattering data with known beam energies to test energy reconstruction methods and interaction models. We find that even in simple interactions where no pions are detected, only a small fraction of events reconstruct to the correct incident energy. More importantly, widely used interaction models reproduce the reconstructed energy distribution only qualitatively and the quality of the reproduction varies strongly with beam energy. This shows both the need and the pathway to improve current models to meet the requirements of next-generation, high-precision experiments such as Hyper-Kamiokande (Japan)3 and DUNE(USA)4.

Coherent Spin Control of Single Molecules on a Surface.

Control of single electron spins constitutes one of the most promising platforms for spintronics, quantum sensing, and quantum information processing. Utilizing single molecular magnets as their hosts establishes an interesting framework since their molecular structure is highly flexible and chemistry-based large-scale synthesis directly provides a way toward scalability. Here, we demonstrate coherent spin manipulation of single molecules on a surface, which we control individually using a scanning tunneling microscope in combination with electron spin resonance. We previously found that iron phthalocyanine (FePc) molecules form a spin-1/2 system when placed on an insulating thin film of magnesium oxide (MgO). Performing Rabi oscillation and Hahn echo measurements, we show that the FePc spin can be coherently manipulated with a phase coherence time T2Echo of several hundreds of nanoseconds. Tunneling current-dependent measurements demonstrate that interaction with the tunneling electrons is the dominating source of decoherence. In addition, we perform Hahn echo measurements on small self-assembled arrays of FePc molecules. We show that, despite additional intermolecular magnetic coupling, spin resonance and T2Echo are much less perturbed by T1 spin flip events of neighboring spins than by the tunneling current. This will potentially allow for individual addressable molecular spins in self-assemblies and with application for quantum information processing.

Fermi Surface Mapping and the Nature of Charge-Density-Wave Order in the Kagome Superconductor CsV3Sb5

The recently discovered family of AV$_3$Sb$_5$ (A: K, Rb Cs) kagome metals possess a unique combination of nontrivial band topology, superconducting ground states, and signatures of electron correlations manifest via competing charge density wave order. Little is understood regarding the nature of the charge density wave (CDW) instability inherent to these compounds and the potential correlation with the accompanying onset of a large anomalous Hall response. To understand the impact of the CDW order on the electronic structure in these systems, we present quantum oscillation measurements on single crystals of CsV$_3$Sb$_5$. Our data provides direct evidence that the CDW invokes a substantial reconstruction of the Fermi surface pockets associated with the vanadium orbitals and the kagome lattice framework. In conjunction with density functional theory modeling, we are able to identify split oscillation frequencies originating from reconstructed pockets built from vanadium orbitals and Dirac-like bands. Complementary diffraction measurements are further able to demonstrate that the CDW instability has a correlated phasing between neighboring V$_3$Sb$_5$ planes. These results provide critical insights into the underlying CDW instability in AV$_3$Sb$_5$ kagome metals and support minimal models of CDW order arising from within the vanadium-based kagome lattice.

TaCo2Te2: An Air‐Stable, High Mobility Van der Waals Material with Probable Magnetic Order

AbstractVan der Waals (vdW) materials are an indispensable part of functional device technology due to their versatile physical properties and ease of exfoliating to the low‐dimensional limit. Among all the compounds investigated so far, the search for magnetic vdW materials has intensified in recent years, fueled by the realization of magnetism in 2D. However, metallic magnetic vdW systems are still uncommon. In addition, they rarely host high‐mobility charge carriers, which is an essential requirement for high‐speed electronic applications. Another shortcoming of 2D magnets is that they are highly air sensitive. Using chemical reasoning, TaCo2Te2 is introduced as an air‐stable, high‐mobility, magnetic vdW material. It has a layered structure, which consists of Peierls distorted Co chains and a large vdW gap between the layers. It is found that the bulk crystals can be easily exfoliated and the obtained thin flakes are robust to ambient conditions after 4 months of monitoring using an optical microscope. Signatures of canted antiferromagntic behavior are also observed at low‐temperature. TaCo2Te2 shows a metallic character and a large, nonsaturating, anisotropic magnetoresistance. Furthermore, the Hall data and quantum oscillation measurements reveal the presence of both electron‐ and hole‐type carriers and their high mobility.

Fermi Surface Modeling of Light‐Rare‐Earth Hexaborides using Positron Annihilation Spectroscopy

2D angular correlation of the positron annihilation radiation (2D‐ACAR) spectra are measured for along high‐symmetry directions and compared with first‐principles calculations based on density functional theory (DFT). This allows the modeling of the Fermi surface in terms of ellipsoid electron pockets centered at X‐points elongated along the Σ axis (Γ direction). The obtained structure is in agreement with quantum oscillation measurements and previous band structure calculations. For the isostructural topologically nontrivial , the similar ellipsoids are connected through necks that have significantly smaller radii in the case of . A theoretical analysis of the 2D‐ACAR spectra is also conducted for including the on‐site repulsion U‐correction to the local density approximation (LDA+U) of the DFT. The similarities of the 2D‐ACAR spectra and the Fermi surface projections of these two compounds allow to infer that both and are topologically trivial correlated metals.

Frequency Stability of AC/DC Interconnected Power Systems with Wind Energy Using Arithmetic Optimization Algorithm-Based Fuzzy-PID Controller

This article proposes an intelligent control strategy to enhance the frequency dynamic performance of interconnected multi-source power systems composing of thermal, hydro, and gas power plants and the high penetration level of wind energy. The proposed control strategy is based on a combination of fuzzy logic control with a proportional-integral-derivative (PID) controller to overcome the PID limitations during abnormal conditions. Moreover, a newly adopted optimization technique namely Arithmetic optimization algorithm (AOA) is proposed to fine-tune the proposed fuzzy-PID controller to overcome the disadvantages of conventional and heuristic optimization techniques (i.e., long time in estimating controller parameters-slow convergence curves). Furthermore, the effect of the high voltage direct current link is taken into account in the studied interconnected power system to eliminate the AC transmission disadvantages (i.e., frequent tripping during oscillations in large power systems–high level of fault current). The dynamic performance analysis confirms the superiority of the proposed fuzzy-PID controller based on the AOA compared to the fuzzy-PID controller based on a hybrid local unimodal sampling and teaching learning-based optimization (TLBO) in terms of minimum objective function value and overshoots and undershoots oscillation measurement. Also, the AOA’s proficiency has been verified over several other powerful optimization techniques; differential evolution, TLBO using the PID controller. Moreover, the simulation results ensure the effectiveness and robustness of the proposed fuzzy-PID controller using the AOA in achieving better performance under several contingencies; different load variations, the high penetration level of the wind power, and system uncertainties compared to other literature controllers adjusting by various optimization techniques.