Miracle-dz/UniFAR-FTUs huggingface dataset:
Realization of a timescale with an accurate optical lattice clock

Optical clocks are not only powerful tools for prime fundamental research, but are also deemed for the redefinition of the SI base unit “second,” as they now surpass the performance of cesium atomic clocks in both accuracy and stability by more than an order of magnitude. However, an important obstacle in this transition has so far been the limited reliability of optical clocks, which made a continuous realization of a timescale impractical. In this paper, we demonstrate how this situation can be resolved and show that a timescale based on an optical clock can be established that is superior to one based on even the best cesium fountain clocks. The paper also gives further proof of the international consistency of strontium lattice clocks on the 10−16 accuracy level, which is another prerequisite for a change in the definition of the second.
Psychological Health in Intensive Care Unit Health Care Workers after the COVID-19 Pandemic

Background: Although the COVID-19 pandemic had an impact on the general population, health care workers (HCWs) constituted one of the groups that were most adversely affected by the associated risks, owing to the significant consequences on their mental health. This study examined these psychological effects on HCWs who cared for COVID-19 patients who were admitted to the intensive care unit in an Italian hospital. Methods: Subjects were administered several self-reported questionnaires: Kessler 10 Psychological Distress Scale (K10), Perceived Stress Scale-10 (PSS), Impact of Event Scale Revised (IES-R), and Post-traumatic Growth Inventory (PTGI), as well as two open-ended questions oriented toward understanding their positive and negative emotional experience and differentiating between two phases of the emergency. Results: Overall, 45% of HCWs showed medium-to-high anxiety/depressive symptoms, whereas 60% presented with medium-to-high levels of perceived stress. In addition, 37% of subjects developed symptoms of PTSD and 50% showed post-traumatic growth in the “appreciation of life” and “new possibilities” dimensions. With regard to the open-ended questions, three themes were identified: quality of workplace relationships, sense of emotional-relational competence, and sense of clinical-technical competence. In addition, two macrocategories of responses were identified in the answers: growth and block. Conclusions: The mental health of HCWs who are involved in the front line of COVID-19 was significantly impacted by this experience, showing high levels of post-traumatic stress and anxiety and depressive symptoms more than 1 year after the emergency began. A qualitative analysis of staff experiences can be a useful guide for structuring interventions and prevention.
Stopping dynamics of ions passing through correlated honeycomb clusters

A combined nonequilibrium Green functions--Ehrenfest dynamics approach is developed that allows for a time-dependent study of the energy loss of a charged particle penetrating a strongly correlated system at zero and finite temperatures. Numerical results are presented for finite inhomogeneous two-dimensional Fermi-Hubbard models, where the many-electron dynamics in the target are treated fully quantum mechanically and the motion of the projectile is treated classically. The simulations are based on the solution of the two-time Dyson (Keldysh-Kadanoff-Baym) equations using the second-order Born, third-order, and $\mathrm{T}$-matrix approximations of the self-energy. As application, we consider protons and helium nuclei with a kinetic energy between 1 and 500 keV/u passing through planar fragments of the two-dimensional honeycomb lattice and, in particular, examine the influence of electron-electron correlations on the energy exchange between projectile and electron system. We investigate the time dependence of the projectile's kinetic energy (stopping power), the electron density, the double occupancy, and the photoemission spectrum. Finally, we show that, for a suitable choice of the Hubbard model parameters, the results for the stopping power are in fair agreement with ab initio simulations for particle irradiation of single-layer graphene.
Deterministic construction of arbitrary $W$ states with quadratically increasing number of two-qubit gates

We propose a quantum circuit composed of $cNOT$ gates and four single-qubit gates to generate a $W$ state of three qubits. This circuit was then enhanced by integrating two-qubit gates to create a $W$ state of four and five qubits. After a couple of enhancements, we show that an arbitrary $W$ state can be generated depending only on the degree of enhancement. The generalized formula for the number of two-qubit gates required is given, showing that an $n$-qubit $W$-state generation can be achieved with quadratically increasing number of two-qubit gates. Also, the practical feasibility is discussed regarding photon sources and various applications of $cNOT$ gates.
Compressible Hydrodynamic Mean-Field Equations in Spherical Geometry and their Application to Turbulent Stellar Convection Data

We present a statistical analysis of turbulent convection in stars within our Reynolds-Averaged Navier Stokes (RANS) framework in spherical geometry which we derived from first principles. The primary results reported in this document include: (1) an extensive set of mean-field equations for compressible, multi-species hydrodynamics, and (2) corresponding mean-field data computed from various simulation models. Some supplementary scale analysis data is also presented. The simulation data which is presented includes: (1) shell convection during oxygen burning in a 23 solar mass supernova progenitor, (2) envelope convection in a 5 solar mass red giant, (3) shell convection during the helium flash, and (4) a hydrogen injection flash in a 1.25 solar mass star. These simulations have been partially described previously in Meakin [2006], Meakin and Arnett [2007a,b, 2010], Arnett et al. [2009, 2010], Viallet et al. [2011, 2013a,b] and Mocak et al. [2009, 2011]. New data is also included in this document with several new domain and resolution configurations as well as some variations in the physical model such as convection zone depth and driving source term. The long term goal of this work is to aid in the development of more sophisticated models for treating hydrodynamic phenomena (e.g., turbulent convection) in the field of stellar evolution by providing a direct link between 3D simulation data and the mean fields which are modeled by 1D stellar evolution codes. As such, this data can be used to test previously proposed turbulence models found in the literature and sometimes used in stellar modeling. This data can also serve to test basic physical principles for model building and inspire new prescriptions for use in 1D evolution codes.
Power of the redshift drift on cosmological models and expansion history

We investigate the power of the velocity drift (�v) on cosmological parameters and expansion history with observational Hubble data (OHD), type Ia supernova (SNIa). We estimate the constraints ofv using the Fisher information matrix based on the model by Pasquini et al. (2005, 2006a). We find that �v with 20 years can reduce the uncertainty of m by more than 42% than available observations. Based on the statistical figures of merit (FoM), we find that in order to match the constraint power of OHD and SNIa, we need 21 and 26 future measurements, respectively. We also quantitatively estimate for the first time the number of years required for the velocity drift to become comparable with current observations on the equation of state w. The statistical FoM indicate that we need at least 12 years to cover current observations. Physically, we could monitor 30 quasars for 30 years to obtain the same accuracy of w. Considering two parameterized deceleration factor q(z), we find that the available observations give an estimation on current value −0.9 . q0 . −0.3. Difference between the two types of q(z) is the precise determination of variation rate dq/dz. For the first model with constant dq/dz, �v with only 10 years provides a much better constraint on it, especially when compared with SNIa. However, we needv for more years in the variable dq/dz model. We find that �v with 30 years reduces the uncertainty of transition redshift to approximately three times better than those of OHD and SNIa.
A Wideband CMOS Power Amplifier With 52% Peak PAE Employing Resistive Shunt Feedback for Sub-6 GHz 5G Applications

This letter presents the design and implementation of a wideband power amplifier (PA) for sub-6 GHz 5G wireless applications. The PA employs a Class-B biased cascode topology with resistive shunt–shunt feedback for wideband response, good linearity, and simultaneous input and output matching. The design equations and stability considerations are laid out and are followed by experimental validation using both static and dynamic measurements. The chip prototype was fabricated in TSMC’s 65 nm CMOS technology. The PA operates from a 3.3 V supply and delivers a maximum power gain of 22.5 dB with a bandwidth of 2.17 GHz between 0.33 and 2.5 GHz, a peak output power of 21.5 dBm, and 52.4% power-added efficiency (PAE) at 1 GHz with >35% PAE over the operating frequency range. In the measurement of an orthogonal frequency-division multiplexing (OFDM) signal with 20 MHz modulation bandwidth and 10 dB peak-to-average power ratio (PAPR) at the average output power of 11 dBm around 1 GHz, EVM of −39 dB was achieved using memoryless polynomial-based digital predistortion (DPD).
THE INTERMEDIATE NEUTRON-CAPTURE PROCESS AND CARBON-ENHANCED METAL-POOR STARS

Carbon-enhanced metal-poor (CEMP) stars in the Galactic Halo display enrichments in heavy elements associated with either the s (slow) or the r (rapid) neutron-capture process (e.g., barium and europium, respectively), and in some cases they display evidence of both. The abundance patterns of these CEMP-s/r stars, which show both Ba and Eu enrichment, are particularly puzzling, since the s and the r processes require neutron densities that are more than ten orders of magnitude apart and, hence, are thought to occur in very different stellar sites with very different physical conditions. We investigate whether the abundance patterns of CEMP-s/r stars can arise from the nucleosynthesis of the intermediate neutron-capture process (the i process), which is characterized by neutron densities between those of the s and the r processes. Using nuclear network calculations, we study neutron capture nucleosynthesis at different constant neutron densities n ranging from 107–1015 cm−3. With respect to the classical s process resulting from neutron densities on the lowest side of this range, neutron densities on the highest side result in abundance patterns, which show an increased production of heavy s-process and r-process elements, but similar abundances of the light s-process elements. Such high values of n may occur in the thermal pulses of asymptotic giant branch stars due to proton ingestion episodes. Comparison to the surface abundances of 20 CEMP-s/r stars shows that our modeled i-process abundances successfully reproduce observed abundance patterns, which could not be previously explained by s-process nucleosynthesis. Because the i-process models fit the abundances of CEMP-s/r stars so well, we propose that this class should be renamed as CEMP-i.
Political Discussions in Homogeneous and Cross-Cutting Communication Spaces

Online platforms, such as Facebook, Twitter, and Reddit, provide users with a rich set of features for sharing and consuming political information, expressing political opinions, and exchanging potentially contrary political views. In such activities, two types of communication spaces naturally emerge: those dominated by exchanges between politically homogeneous users and those that allow and encourage crosscutting exchanges in politically heterogeneous groups. While research on political talk in online environments abounds, we know surprisingly little about the potentially varying nature of discussions in politically homogeneous spaces as compared to cross-cutting communication spaces. To fill this gap, we use Reddit to explore the nature of political discussions in homogeneous and cross-cutting communication spaces. In particular, we develop an analytical template to study interaction and linguistic patterns within and between politically homogeneous and heterogeneous communication spaces. Our analyses reveal different behavioral patterns in homogeneous and cross-cutting communications spaces. We discuss theoretical and practical implications in the context of research on political talk online.
Reading off the nongeometric scalar potentials via the topological data of the compactifying Calabi-Yau manifolds

In the context of studying the 4D effective potentials of type IIB non-geometric flux compactifications, this article has a twofold goal. First, we present a modular invariant symplectic rearrangement of the tree level non-geometric scalar potential arising from a flux superpotential which includes the S-dual pairs of non-geometric fluxes $(Q, P)$, the standard NS-NS and RR three-form fluxes $(F_3, H_3)$ and the geometric flux ($\omega$). This `symplectic formulation' is valid for arbitrary numbers of K\"ahler moduli, and the complex structure moduli which are implicitly encoded in a set of symplectic matrices. In the second part, we further explicitly rewrite all the symplectic ingredients in terms of saxionic and axionic components of the complex structure moduli. The same leads to a compact form of the generic scalar potential being explicitly written out in terms of all the real moduli/axions. Moreover, the final form of the scalar potential needs only the knowledge of some topological data (such as hodge numbers and the triple intersection numbers) of the compactifying (CY) threefolds and their respective mirrors. Finally, we demonstrate how the same is equivalent to say that, for a given concrete example, various pieces of the scalar potential can be directly read off from our generic proposal, without the need of starting from the K\"ahler- and super-potentials.
Multiple Sulfur Corrosion Simulation on the Oil–Paper Insulation System Under Synergistic Electric and Thermal Fields

Sulfur corrosion in transformers results in insulation deterioration failures. Therefore, in this study, multiple sulfur corrosion was simulated on the oil–paper insulation system. The mechanical properties and hydrogen bond of the insulating paper as well as the mean square displacement (MSD) and shear viscosity of the insulating oil were investigated under different combinations of electric and thermal fields. The electric field could promote the degradation of the elastic modulus of cellulose. The influence of the ac electric field on the modulus is not as obvious as that of the dc electric field. The temperature has a significant effect on the modulus parameters. With the increase in temperature, the elastic modulus decreases considerably. The radial distribution function (RDF) of the model was also investigated. Cellulose can easily form intramolecular hydrogen bonds under ac electric fields. Furthermore, intermolecular hydrogen bonds are easily formed under a dc electric field. The shear viscosity of insulating oil decreases with the increase in temperature. The presence of the electric field could increase shear viscosity. The results of the study can provide some reference for the microscopic mechanism of multiple corrosive sulfides and investigate effective protection techniques against sulfur corrosion.
Equation of state of imbalanced cold matter from chiral perturbation theory

We study the thermodynamic properties of matter at vanishing temperature for nonextreme values of the isospin chemical potential and of the strange quark chemical potential. From the leading-order pressure obtained by maximizing the static chiral Lagrangian density, we derive a simple expression for the equation of state in the pion condensed phase and in the kaon condensed phase. We find an analytical expression for the maximum of the ratio between the energy density and the Stefan-Boltzmann energy density and for the isospin chemical potential at the peak, both in good agreement with lattice simulations of quantum chromodynamics. We speculate on the location of the crossover from the Bose-Einstein condensate state to the Bardeen-Cooper-Schrieffer state by a simple analysis of the thermodynamic properties of the system. For μI≳2mπ, the leading-order chiral perturbation theory breaks down; for example, it underestimates the energy density of the system and leads to a wrong asymptotic behavior.
Luminosity dependence of the cyclotron line and evidence for the accretion regime transition in V 0332+53

We report on the analysis of NuSTAR observations of the Be-transient X-ray pulsar V 0332+53 during the giant outburst in 2015 and another minor outburst in 2016. We confirm the cyclotron-line energy–luminosity correlation previously reported in the source and the line energy decrease during the giant outburst. Based on 2016 observations, we find that a year later the line energy has increased again essentially reaching the pre-outburst values. We discuss this behaviour and conclude that it is likely caused by a change of the emission region geometry rather than previously suggested accretion-induced decay of the neutron stars magnetic field. At lower luminosities, we find for the first time a hint of departure from the anticorrelation of line energy with flux, which we interpret as a transition from super- to sub-critical accretion associated with the disappearance of the accretion column. Finally, we confirm and briefly discuss the orbital modulation observed in the outburst light curve of the source.
Production of heavy sterile neutrinos from vector boson decay at electroweak temperatures

In the standard model extended with a seesaw mass matrix, we study the production of sterile neutrinos from the decay of vector bosons at $T\simeq M_{W,Z}$. We derive a general quantum kinetic equation for the production of sterile neutrinos and their effective mixing angles valid in a wide range of temperature, to all orders in interactions of the standard model, and to leading order mixing angle $\theta \ll 1$. Production rates and effective mixing angles depend sensitively on helicity. Positive helicity states interact more weakly with the medium and their effective mixing angle is not modified significantly whereas the mixing angle for negative helicity is strongly suppressed by the medium. If $M_s \lesssim 8.35\,\mathrm{MeV}$, there are fewer states with negative helicity produced than those with positive helicity. There is an MSW resonance in the absence of lepton asymmetry, but is screened by the damping rate, without production enhancement. Negative helicity states freeze-out at $T^-_f\simeq 5\,\mathrm{GeV}$ and positive helicity states freeze-out at $T^+_f \simeq 8\,\mathrm{GeV}$, both distributions are far from thermal. Negative helicity states feature a broader momentum distribution than that for those with positive helicity. Sterile neutrinos produced via vector boson decay do not satisfy the abundance, lifetime and cosmological constraints to be the sole dark matter component in the universe. We discuss how massive sterile neutrinos might solve the $^{7}Li$ problem, albeit at the very edge of the possible parameter space. A heavy sterile neutrino with a mass of a few MeV could decay into light sterile neutrinos, of a few keV in mass, that contribute to warm dark matter. We argue that heavy sterile neutrinos with lifetime $\leq 1/H_0$ reach local thermodynamic equilibrium.
Deep-Learning-Based Cyber-Physical System Framework for Real-Time Industrial Operations

Automation in the industry can improve production efficiency and human safety when performing complex and hazardous tasks. This paper presented an intelligent cyber-physical system framework incorporating image processing and deep-learning techniques to facilitate real-time operations. A convolutional neural network (CNN) is one of the most widely used deep-learning techniques for image processing and object detection analysis. This paper used a variant of a CNN known as the faster R-CNN (R stands for the region proposals) for improved efficiency in object detection and real-time control analysis. The control action related to the detected object is exchanged with the actuation system within the cyber-physical system using a real-time data exchange (RTDE) protocol. We demonstrated the proposed intelligent CPS framework to perform object detection-based pick-and-place operations in real time as they are one of the most widely performed operations in quality control and industrial systems. The CPS consists of a camera system that is used for object detection, and the results are transmitted to a universal robot (UR5), which then picks the object and places it in the right location. Latency in communication is an important factor that can impact the quality of real-time operations. This paper discussed a Bayesian approach for uncertainty quantification of latency through the sampling–resampling approach, which can later be used to design a reliable communication framework for real-time operations.
Geometric orbital susceptibility: Quantum metric without Berry curvature

The orbital magnetic susceptibility of an electron gas in a periodic potential depends not only on the zero field energy spectrum but also on the geometric structure of cell-periodic Bloch states which encodes interband effects. In addition to the Berry curvature, we explicitly relate the orbital susceptibility of two-band models to a quantum metric tensor defining a distance in Hilbert space. Within a simple tight-binding model allowing for a tunable Bloch geometry, we show that interband effects are essential even in the absence of Berry curvature. We also show that for a flat band model, the quantum metric gives rise to a very strong orbital paramagnetism.
Timing properties of gamma-ray bursts detected by SPI-ACS detector onboard INTEGRAL

We study timing properties of a large sample of gamma-ray bursts (GRB) detected by the Anti-Coincidence Shield (ACS) of the SPI spectrometer of INTEGRAL telescope. We identify GRB-like events in the SPI-ACS data. The data set under investigation is the history of count rate of the SPI-ACS detector recorded with a binning of 50 ms over the time span of ~10 yr. In spite of the fact that SPI-ACS does not have imaging capability, it provides high statistics signal for each GRB event, because of its large effective area. We classify all isolated excesses in the SPI-ACS count rate into three types: short spikes produced by cosmic rays, GRBs and Solar flare induced events. We find some ~1500 GRB-like events in the 10 yr exposure. A significant fraction of the GRB-like events identified in SPI-ACS occur in coincidence with triggers of other gamma-ray telescopes and could be considered as confirmed GRBs. We study the distribution of durations of the GRBs detected by SPI-ACS and find that the peak of the distribution of long GRBs is at ~ 20, i.e. somewhat shorter than for the long GRBs detected by BATSE. Contrary to the BATSE observation, the population of short GRBs does not have any characteristic time scale. Instead, the distribution of durations extends as a powerlaw to the shortest time scale accessible for SPI-ACS, < 50 ms. We also find that a large fraction of long GRBs has a characteristic variability time scale of the order of 1 s. We discuss the possible origin of this time scale.