Miracle-dz/UniFAR-FTUs huggingface dataset:
Remarks on input to output stability

The property of input to output stability (IOS) was introduced about 10 years ago (E.D. Sontag, 1989), but most theoretical developments have until now dealt mainly with the special case of input to state stability. The article presents a small-gain theorem for IOS operators, as well as alternative properties and Lyapunov characterizations dealing with the IOS property for state-space systems.
Crystalline electric field of Ce in trigonal symmetry: 
CeIr3Ge7
 as a model case

The crystalline electric field (CEF) of Ce3+ in trigonal symmetry has recently become of some relevance, for instance, in the search of frustrated magnetic systems. Fortunately, it is one of the CEF case in which a manageable analytic solution can be obtained. Here, we present this solution for the general case, and use this result to determine the CEF scheme of the new compound CeIr3Ge7 with the help of T-dependent susceptibility and isothermal magnetization measurements. The resulting CEF parameters B20 = 34.4 K, B40 = 0.82 K and B43 = 67.3 K correspond to an exceptional large CEF splittings of the first and second excited levels, 374 K and 1398 K, and a large mixing between the +-|5/2> and the -+|1/2> states. This indicates a very strong easy plane anisotropy with an unusual small c-axis moment. Using the same general expressions, we show that the properties of the recently reported system CeCd3As3 can also be described by a similar CEF scheme, providing a much simpler explanation for its magnetic properties than the initial proposal. Moreover, a similar strong easy plane anisotropy has also been reported for the two compounds CeAuSn and CePdAl4Ge2, indicating that the CEF scheme elaborated here for CeIr3Ge7 corresponds to an exemplary case for Ce3+ in trigonal symmetry.
Apodized and chirped fiber Bragg gratings for optical communication systems: influence of grating profile on spectral reflectance

In this paper, the simulations of the reflectance of the apodized and chirped Fiber Bragg gratings (FBGs) are presented. The reflectances of apodized FBGs with different modulations of the refractive index were simulated. The results show that reflected light is concentrated to the main reflectance line with negligible sidelobes. Simulations of linearly chirped FBGs show that sharp reflectance lines can be achieved which makes this kind of FBGs suitable candidates for wavelength multiplexing/demultiplexing.
Radio-selected Galaxies in Very Rich Clusters at z ≤ 0.25. I. Multiwavelength Observations and Data Reduction Techniques

Radio observations were used to detect the "active" galaxy population within rich clusters of galaxies in a nonbiased manner that is not plagued by dust extinction or the K-correction. We present wide-field radio, optical (imaging and spectroscopy), and ROSAT All-Sky Survey (RASS) X-ray data for a sample of 30 very rich Abell (R ≥ 2) clusters with z ≤ 0.25. The VLA radio data samples the ultrafaint radio (L1.4 ≥ 2 × 1022 W Hz-1) galaxy population within these extremely rich clusters for galaxies with MR ≤ -21. This is the largest sample of low-luminosity 20 cm radio galaxies within rich Abell clusters collected to date. The radio-selected galaxy sample represents the starburst (star formation rate ≥5 M⊙ yr-1) and active galactic nuclei populations contained within each cluster. Archival and newly acquired redshifts were used to verify cluster membership for most (∼95%) of the optical identifications. Thus, we can identify all the starbursting galaxies within these clusters, regardless of the level of dust obscuration that would affect these galaxies being identified from their optical signature. Cluster sample selection, observations, and data reduction techniques for all wavelengths are discussed.
Instabilities of Transonic Turbulent Flow over a Flat-Sided Wedge

The transonic turbulent two-dimensional airflow over a symmetric flat-sided double wedge is studied numerically. Solutions of the Reynolds-averaged Navier-Stokes equations are obtained with ANSYS-18.2 CFX finite-volume solver of second order accuracy on a fine mesh. The solutions demonstrate an extreme sensitivity of the flow field and lift coefficient to variation of the angle of attack α or free-stream Mach number M∞. Non-unique flow regimes and hysteresis in certain bands of α and M∞ are identified. Interaction of shock waves and local supersonic regions is discussed. The study confirms a concept of shock wave instability due to a coalescence/rupture of supersonic regions. In addition to the instability of shock wave locations, the numerical simulation shows a buffet onset, i.e., self-exciting oscillations due to instability of a boundary layer separation at the rear of wedge. Curious flow regimes with positive lift at negative angles α and, vice versa, with negative lift at positive angles α, are pointed out. A piecewise continuous dependence of the lift coefficient on two free-stream parameters, α and M∞, is discussed.
Crypto Trading and Bitcoin Prices: Evidence from a New Database of Retail Adoption

Prices for cryptocurrencies have undergone multiple boom-bust cycles, together with ongoing entry by retail investors. To investigate the drivers of crypto adoption, we assemble a novel publicly available database on retail use of crypto exchange apps at daily frequency for 95 countries over 2015–22. We show that a rising Bitcoin price is followed by entry of new users, in particular among more risk-seeking segments of the population. Moreover, we find that when prices rise larger holders sell, likely making a return at retail users’ expense. We confirm these findings by exploiting an exogenous decline in the Bitcoin price during the social unrest in Kazakhstan in early 2022.
Buffer-Enhanced Electrical-Pulse-Induced Resistive Memory Effect in Thin Film Perovskites

A multilayer perovskite thin-film resistive memory device composed of a Pr0.7Ca0. 3MnO3 (PCMO) perovskite oxide epitaxial layer on a YBa2Cu3O7-δ (YBCO) thin-film bottom electrode, a thin yttria-stabilized zirconia (YSZ) buffer layer grown on the PCMO layer, and a gold thin-film top electrode has been developed. With the addition of the YSZ buffer layer, the pulse voltage needed to switch the device is significantly reduced and the resistance-switching ratio is increased compared to a non buffered resistive memory device, which is very important for device fabrication. The magnetic field effect on the multilayer structure resistance at various temperatures shows colossal magnetoresistance (CMR) behavior for both high and low resistance states, implying a bulk material component in the switch behavior. The multilayer thin-film lattice structure has been further characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM) analyses, which indicate a high-quality heterostructure. Current imaging atomic force microscopy (I-AFM) analysis indicated nanogranular conductivity distributed uniformly throughout the PCMO film surface.
Quantum eigenstate tomography with qubit tunneling spectroscopy

Measurement of the energy eigenvalues (spectrum) of a multi-qubit system has recently become possible by qubit tunneling spectroscopy (QTS). In the standard QTS experiments, an incoherent probe qubit is strongly coupled to one of the qubits of the system in such a way that its incoherent tunneling rate provides information about the energy eigenvalues of the original (source) system. In this paper, we generalize QTS by coupling the probe qubit to many source qubits. We show that by properly choosing the couplings, one can perform projective measurements of the source system energy eigenstates in an arbitrary basis, thus performing quantum eigenstate tomography. As a practical example of a limited tomography, we apply our scheme to probe the eigenstates of a kink in a frustrated transverse Ising chain.
ISAJET 7.40: A Monte Carlo Event Generator for $pp, \bar pp$, and $e^+e^-$ Reactions

ISAJET is a Monte Carlo program which simulates $pp, \bar pp$ and $e^+e^-$ interactions at high energies. This document summarizes the physics underlying the program and describes how to use it. New features of Version 7.40 include generation of $W+H$ and $Z+H$ events, non-minimal GMSB models, and use of the experimental $\alpha_s(M_Z)$ by default.
Submillimeter surveys of galaxy samples

This thesis aims to gain a better understanding of dusty galaxies by studying the thermal emission of interstellar dust at submillimeter (submm) wavelengths. We conduct 350um observations of two galaxy samples selected based on entirely different criteria, using the Submillimeter High Angular Resolution Camera II (SHARC-II, Dowell et al. 2003) at the 10.4m Caltech Submillimeter Observatory (CSO). The first galaxy sample consists of 18 luminous infrared galaxies (LIGs) in the local Universe (0.003 <= z <= 0.042). We estimate the global properties in this galaxy sample; dust temperature (T_d = 38.6 ± 7.7 K), emissivity index (beta = 1.6 ± 0.3), far-infrared (FIR) luminosity (L_{fir} = 10^11.2±0.6 L_odot}) and dust mass (M_d = 10^7.4±0.6 M_odot$). Guided by theoretical considerations and laboratory measurements, we derive a T_d-beta inverse correlation for the local LIG sample; T_d = [5.03 imes 10^9]^1/4.46 + beta. The second galaxy sample consists of 36 ultraluminous infrared galaxies (ULIGs) at moderate redshifts (0.1 < z < 1.0), out of which 28 galaxies are detected. The newly acquired 350um data, in combination with the pre-existing IRAS 60um and 100um data, leads to meaningful estimates of the global properties in these galaxies for the first time; T_d = 40.9 ± 6.9K, L_{fir} = 10^12.2±0.5 L_odot$, M_d = 10^8.3±0.3 M_odot$ and intense starburst activity (SFR = 10^2.5±0.5 L_odot,yr^-1). There is strong circumstantial evidence that the T_d-beta inverse correlation observed in the local LIG sample remains valid in ULIGs at moderate redshifts. We find that the FIR-radio correlation observed in local star-forming galaxies continues to hold for ULIGs over the redshift range of 0.1 < z < 1.0 and dust heating originates predominantly from star formation. L_fir and T_d derived for dusty galaxy samples over a wide range of redshifts show significant scatter, due to differing selection biases and variations in dust mass and grain properties. We argue that the observed T_d, as a large-scale SED parameter, is linked to the global star formation efficiency (SFE) and the spatial extent characteristic of dominant star formation in a galaxy.
IN-SYNC. VII. Evidence for a Decreasing Spectroscopic Binary Fraction (from 1 to 100 Myr) within the IN-SYNC Sample

We study the occurrence of spectroscopic binaries in young star-forming regions using the INfrared Spectroscopy of Young Nebulous Clusters (IN-SYNC) survey, carried out in SDSS-III with the APOGEE spectrograph. Multi-epoch observations of thousands of low-mass stars in Orion A, NGC 2264, NGC 1333, IC 348, and the Pleiades have been carried out, yielding H-band spectra with a nominal resolution of R = 22,500 for sources with H < 12 mag. Radial velocity precisions of ∼0.3 were achieved, which we use to identify radial velocity variations indicative of undetected companions. We use Monte Carlo simulations to assess the types of spectroscopic binaries to which we are sensitive, finding sensitivity to binaries with orbital periods days, for stars with and < 100 . Using Bayesian inference, we find evidence for a decline in the spectroscopic binary fraction, by a factor of 3–4, from the age of our pre-main-sequence (PMS) sample to the Pleiades age . The significance of this decline is weakened if spot-induced radial-velocity jitter is strong in the sample, and is only marginally significant when comparing any one of the PMS clusters against the Pleiades. However, the same decline in both sense and magnitude is found for each of the five PMS clusters, and the decline reaches a statistical significance of greater than 95% confidence when considering the PMS clusters jointly. Our results suggest that dynamical processes disrupt the widest spectroscopic binaries ( days) as clusters age, indicating that this occurs early in the stars’ evolution, while they still reside within their nascent clusters.
The enumeration of graphs in the Feynman-Dyson technique

As an aid to practical calculations, and as a first step in determining whether field theories that can be renormalized lead to convergent perturbation expansions, the number of graphs that can be drawn for each stage of approximation is investigated. Using the idea of a normal product of operators, a simple method is given for finding the number of Feynman-Dyson graphs, with n vertices, that can be drawn when the interaction Hamiltonian density is of a general type. By solving a difference equation approximately, it is shown that the number of graphs remaining after the removal of those containing subgraphs of a specified type is asymptotically equal to the total number of unmodified graphs. Also it is shown that the number of graphs that can be drawn with n vertices increases very rapidly with n, no matter how many external lines are present, and this rapid increase still occurs even when the class of irreducible graphs alone is considered. Thus the perturbation expansions of field theory cannot converge unless the matrix elements decrease with correspondingly great rapidity as n increases.
Establishing the Validity and Reliability of a Program Evaluation Questionnaire using Rasch Measurement Model

This study was conducted to establish the validity and reliability of the evaluation questionnaire for the 12th Regional Congress of the Search For SEAMEO Young Scientist (SSYS) 2022 using the Rasch Measurement Model that was aided by the Winsteps software. The questionnaire contains 24 items that evaluate the Congress's objectives, inputs, as well as event management and administration. Each item is rated on a 4-point rating scale. The instrument was administered at the end of the 3-days SSYS Congress held virtually in which 1891 participants submitted their responses. The establishment of validity and reliability of this questionnaire is crucial before further analysis is carried out. The Rasch Model analysis showed that the reliability index of the respondents was 0.87 and person separation is 2.60, while the item reliability index is 0.96 with an item separation index of 5.08. Item polarity indicates that the point measure correlation (PTMEA CORR) for the 24 items is between 0.67 to 0.76. In terms of item fit, the results indicated one misfit item that needs improvement in the future. The Principal Component Analysis (PCA) shows that almost all the items are unidimensional and intended to measure a similar trait. All these indicate the reliability of the questionnaire, and researchers can proceed with further data analysis to evaluate the 12th Regional Congress of the SSYS 2022.
Experimental Studies of Coaxial Jet Flows

An experimental study was carried out to investigate the effect of coaxial nozzle operating conditions on near-field jet plume development. The study was conducted in a low speed water tunnel as well as in a high-speed airflow nozzle test facility. Laser Doppler Anemometry (LDA) and Laser Induced Fluorescence (LIF) techniques were employed to identify the flow structure as well as the mean velocity and turbulence structure of a coaxial nozzle under low speed flow conditions. Schlieren flow visualization, LDA and nozzle wall static pressure measurement surveys were performed in high speed flows. The effect of a nozzle shroud on jet development was studied and found very effective on suppression of the shock cells and on reduction of turbulence levels within the core region. The effect of the outer and inner Nozzle Pressure Ratios on shock cell structure and the nozzle internal wall pressure field were documented. LDA measurements in the water tunnel confirmed that the flow pattern produced of the Reynolds numbers and velocity ratios selected for this study was typical of practically occurring developing jet flow fields. Sufficient measured profiles of velocities, turbulence quantities and nozzle wall static pressures as well as jet plume images have been captured to serve as benchmark validation data for time-averaged turbulence-model-based RANS CFD predictions.
Lessons For Enhancing Competitive Advantage: Dynamic Capabilities Framework

In turbulent business environments, building and exploiting competitive advantages necessitate manufacturing companies to start new strategic initiatives. For this purpose, new product development (NPD) should be seen as dynamic capabilities (DC) that enable companies to create a better match between the configuration of a firm’s resources and changing conditions. This study aims to make use of the operationalised DC model including sensing, seizing and reconfiguration capacities in a hierarchical decision structure. A multi-case-studies approach is employed for validation of the DC assessment model on automotive companies which are categorized as European, Japanese and American. The qualitative analysis reveals the appropriate management practices underlying the micro-foundation of DC at the operational management level, which can help chief executives to implement the appropriate strategy for enhancing NPD performance. Managers can creatively leverage their companies’ DC components by conceiving of different ways to integrate these DC components into NPD projects.
Rule for Mode Coupling Efficiency in Optical Waveguide Crossing

Crossing an optical waveguide requires a beam coupling from free space to waveguide at the entrance plane and another beam coupling from waveguide to free space at the exit plane of the waveguide. The aim of this paper is to provide a simple rule expressing the relationship between the involved numbers of free and guided modes that efficiently rebuild the field at each end of the waveguide. Using a numerical program built on Maple software, the rule was determined to be effective independently of the ratio between the beam spot size and the waveguide radius.
High-dimensional frequency-bin entangled photons in an optical microresonator on a chip

Quantum frequency combs from chip-scale integrated sources are promising candidates for scalable and robust quantum information processing (QIP). However, to use these quantum combs for frequency domain QIP, demonstration of entanglement in the frequency basis, showing that the entangled photons are in a coherent superposition of multiple frequency bins, is required. We present a verification of qubit and qutrit frequency-bin entanglement using an on-chip quantum frequency comb with 40 mode pairs, through a two-photon interference measurement that is based on electro-optic phase modulation. Our demonstrations provide an important contribution in establishing integrated optical microresonators as a source for high-dimensional frequency-bin encoded quantum computing, as well as dense quantum key distribution.
Dynamics of a single electron in the disordered Holstein model

We study, at zero temperature, the dynamics of a single electron in a Holstein model augmented by site-diagonal, binary-alloy{endash}type disorder. The average over the phonon vacuum and the alloy configurations is performed within a generalized dynamic coherent potential approximation. We present numerical results for a Bethe lattice with infinite coordination number. In particular, we investigate, in the intermediate electron-phonon coupling regime, the spectral and diffusion properties in the vicinity of the high-energy edge of the lowest polaronic subband. To characterize the diffusion properties, we define a spectrally resolved delocalization time, which is, for a given energy, the characteristic time scale on which the electron leaves a given site. We find the delocalization times substantially enhanced for states with a large phonon content, i.e., in the absence (presence) of alloy-type disorder at the high-energy edge(s) of the polaronic subband (minisubbands). According to their delocalization times, we discriminate between {open_quotes}fast{close_quotes} quasiparticlelike and {open_quotes}sluggish{close_quotes} defectlike polaron states and qualitatively address the issue of trapping of an electronic carrier.
Extended thermodynamics of self-gravitating skyrmions

A modification of the hedgehog ansatz has recently lead to novel exact black hole solutions with selfgravitating SU(2) Skyrme fields. Considering a negative cosmological constant the black holes are not asymptotically anti-de Sitter (AdS) but rather asymptote to an AdS version of Barriola–Vilenkin spacetime. We examine the thermodynamics of the system interpreting the cosmological constant as a bulk pressure. We use the standard counterterm method to obtain a finite Euclidean action. For a given coupling of the matter action the system behaves as does a charged AdS black hole in the fixed charged ensemble. We find that in the limit case when the Skyrme model becomes a nonlinear sigma model the system exhibits a first order phase transition of Hawking–Page type. The universality class of these Einstein–Skyrme black holes is that of van der Waals.
Out-of-equilibrium evolution of quantum fields in the hybrid model with quantum back reaction

The hybrid model with a scalar "inflaton" field coupled to a "Higgs" field with a broken symmetry potential is one of the promising models for inflation and (p)reheating after inflation. We consider the nonequilibrium evolution of the quantum fields of this model with quantum back reaction in the Hartree approximation, in particular the transition of the Higgs field from the metastable "false vacuum" to the broken symmetry phase. We have performed the renormalization of the equations of motion, of the gap equations and of the energy density, using dimensional regularization. We study the influence of the back reaction on the evolution of the classical fields and of the quantum fluctuations. We observe that back reaction plays an important role over a wide range of parameters. Some implications of our investigation for the preheating stage after cosmic inflation are presented.
The curtain remains open: NGC 2617 continues in a high state

Optical and near-infrared photometry, optical spectroscopy, and soft X-ray and UV monitoring of the changing look active galactic nucleus NGC 2617 show that it continues to have the appearance of a type-1 Seyfert galaxy. An optical light curve for 2010-2016 indicates that the change of type probably occurred between 2010 October and 2012 February and was not related to the brightening in 2013. In 2016 NGC 2617 brightened again to a level of activity close to that in 2013 April. We find variations in all passbands and in both the intensities and profiles of the broad Balmer lines. A new displaced emission peak has appeared in H$\beta$. X-ray variations are well correlated with UV-optical variability and possibly lead by $\sim$ 2-3 d. The $K$ band lags the $J$ band by about 21.5 $\pm$ 2.5 d. and lags the combined $B+J$ filters by $\sim$ 25 d. $J$ lags $B$ by about 3 d. This could be because $J$-band variability arises from the outer part of the accretion disc, while $K$-band variability comes from thermal re-emission by dust. We propose that spectral-type changes are a result of increasing central luminosity causing sublimation of the innermost dust in the hollow biconical outflow. We briefly discuss various other possible reasons that might explain the dramatic changes in NGC 2617.