Miracle-dz/UniFAR-FTUs huggingface dataset:
From cosmic deceleration to acceleration: new constraints from SN Ia and BAO/CMB

We use type Ia supernovae (SN Ia) data in combination with recent baryonic acoustic oscillations (BAO) and cosmic microwave background (CMB) observations to constrain a kink-like parametrization of the deceleration parameter (q). This q-parametrization can be written in terms of the initial (qi) and present (q0) values of the deceleration parameter, the redshift of the cosmic transition from deceleration to acceleration (zt) and the redshift width of such transition (τ). By assuming a flat space geometry, qi = 1/2 and adopting a likelihood approach to deal with the SN Ia data we obtain, at the 68% confidence level (C.L.), that: zt = 0.56+0.13−0.10, τ = 0.47+0.16−0.20 and q0 = −0.31+0.11−0.11 when we combine BAO/CMB observations with SN Ia data processed with the MLCS2k2 light-curve fitter. When in this combination we use the SALT2 fitter we get instead, at the same C.L. : zt = 0.64+0.13−0.07, τ = 0.36+0.11−0.17 and q0 = −0.53+0.17−0.13. Our results indicate, with a quite general and model independent approach, that MLCS2k2 favors Dvali-Gabadadze-Porrati-like cosmological models, while SALT2 favors ΛCDM-like ones. Progress in determining the transition redshift and/or the present value of the deceleration parameter depends crucially on solving the issue of the difference obtained when using these two light-curve fitters.
Conjugate degradability and the quantum capacity of cloning channels

A quantum channel is conjugate degradable if the channel’s environment can be simulated up to complex conjugation using the channel’s output. For all such channels, the quantum capacity can be evaluated using a single-letter formula. In this article we introduce conjugate degradability and establish a number of its basic properties. We then use it to calculate the quantum capacity of N to N+1 and 1 to M universal quantum cloning machines as well as the quantum capacity of a channel that arises naturally when data are being transmitted to an accelerating receiver. All the channels considered turn out to have strictly positive quantum capacity, meaning they could be used as part of a communication system to send quantum states reliably.
OPENING THE 21 cm EPOCH OF REIONIZATION WINDOW: MEASUREMENTS OF FOREGROUND ISOLATION WITH PAPER

We present new observations with the Precision Array for Probing the Epoch of Reionization with the aim of measuring the properties of foreground emission for 21 cm epoch of reionization (EoR) experiments at 150 MHz. We focus on the footprint of the foregrounds in cosmological Fourier space to understand which modes of the 21 cm power spectrum will most likely be compromised by foreground emission. These observations confirm predictions that foregrounds can be isolated to a “wedge”-like region of two-dimensional (k⊥, k∥)-space, creating a window for cosmological studies at higher k∥ values. We also find that the emission extends past the nominal edge of this wedge due to spectral structure in the foregrounds, with this feature most prominent on the shortest baselines. Finally, we filter the data to retain only this “unsmooth” emission and image its specific k∥ modes. The resultant images show an excess of power at the lowest modes, but no emission can be clearly localized to any one region of the sky. This image is highly suggestive that the most problematic foregrounds for 21 cm EoR studies will not be easily identifiable bright sources, but rather an aggregate of fainter emission.
Test for anisotropy in the mean of the CMB temperature fluctuation in spherical harmonic space

The standard models of inflation predict statistically homogeneous and isotropic primordial fluctuations, which should be tested by observations. In this paper we illustrate a method to test the statistical isotropy of the mean of the cosmic microwave background temperature fluctuations in the spherical harmonic space and apply the method to the Wilkinson Microwave Anisotropy Probe seven-year observation data. A classical method to test a mean, like the simple Student's t test, is not appropriate for this purpose because the Wilkinson Microwave Anisotropy Probe data contain anisotropic instrumental noise and suffer from the effect of the mask for the foreground emissions which breaks the statistical independence. Here we perform a band-power analysis with Monte Carlo simulations in which we take into account the anisotropic noise and the mask. We find evidence of a nonzero mean at 99.93% confidence level in a particular range of multipoles. The evidence against the zero-mean assumption as a whole is still significant at the 99% confidence level even if the fact is taken into account that we have tested multiple ranges.
The HARPS search for southern extrasolar planets - XXV. Results from the metal-poor sample

Searching for extrasolar planets around stars of different metallicity may provide strong constraints to the models of planet formation and evolution. In this paper we present the overall results of a HARPS (a high-precision spectrograph mostly dedicated to deriving precise radial velocities) program to search for planets orbiting a sample of 104 metal-poor stars (selected [Fe/H] below −0.5). Radial velocity time series of each star are presented and searched for signals using several statistical diagnostics. Stars with detected signals are presented, including 3 attributed to the presence of previously announced giant planets orbiting the stars HD171028, HD181720, and HD190984. Several binary stars and at least one case of a coherent signal caused by activity-related phenomena are presented. One very promising new, possible giant planet orbiting the star HD107094 is discussed, and the results are analyzed in light of the metallicity-giant planet correlation. We conclude that the frequency of giant planets orbiting metal-poor stars may be higher than previously thought, probably reflecting the higher precision of the HARPS survey. In the metallicity domain of our sample, we also find evidence that the frequency of planets is a steeply rising function of the stellar metal content, as found for higher metallicity stars.
THE OBSERVATIONAL AND THEORETICAL TIDAL RADII OF GLOBULAR CLUSTERS IN M87

Globular clusters have linear sizes (tidal radii) which theory tells us are determined by their masses and by the gravitational potential of their host galaxy. To explore the relationship between observed and expected radii, we utilize the globular cluster population of the Virgo giant M87. Unusually deep, high signal-to-noise images of M87 are used to measure the effective and limiting radii of approximately 2000 globular clusters. To compare with these observations, we simulate a globular cluster population that has the same characteristics as the observed M87 cluster population. Placing these simulated clusters in the well-studied tidal field of M87, the orbit of each cluster is solved and the theoretical tidal radius of each cluster is determined. We compare the predicted relationship between cluster size and projected galactocentric distance to observations. We find that for an isotropic distribution of cluster velocities, theoretical tidal radii are approximately equal to observed limiting radii for Rgc < 10 kpc. However, the isotropic simulation predicts a steep increase in cluster size at larger radii, which is not observed in large galaxies beyond the Milky Way. To minimize the discrepancy between theory and observations, we explore the effects of orbital anisotropy on cluster sizes, and suggest a possible orbital anisotropy profile for M87 which yields a better match between theory and observations. Finally, we suggest future studies which will establish a stronger link between theoretical tidal radii and observed radii.
CONSTRAINING WARM DARK MATTER MASS WITH COSMIC REIONIZATION AND GRAVITATIONAL WAVES

We constrain the warm dark matter (WDM) particle mass with observations of cosmic reionization and CMB optical depth. We suggest that the gravitational waves (GWs) from stellar-mass black holes (BHs) could give a further constraint on WDM particle mass for future observations. The star formation rates (SFRs) of Population I/II (Pop I/II) and Population III (Pop III) stars are also derived. If the metallicity of the universe is enriched beyond the critical value of , the star formation shifts from Pop III to Pop I/II stars. Our results show that the SFRs are quite dependent on the WDM particle mass, especially at high redshifts. Combined with the reionization history and CMB optical depth derived from the recent Planck mission, we find that the current data require the WDM particle mass to be in a narrow range of . Furthermore, we suggest that the stochastic gravitational wave background (SGWB) produced by stellar BHs could give a further constraint on the WDM particle mass for future observations. For , with Salpeter (Chabrier) initial mass function (IMF), the SGWB from Pop I/II BHs has a peak amplitude of at , while the GW radiation at Hz is seriously suppressed. For , the SGWB peak amplitude is the same as that for , but a little lower at low frequencies. Therefore, it is hard to constrain the WDM particle mass by the SGWB from Pop I/II BHs. To assess the detectability of the GW signal, we also calculate the signal-to-noise ratios (S/N), which are and for and for the Einstein Telescope with Salpeter (Chabrier) IMF, respectively. The SGWB from Pop III BHs is very dependent on the WDM particle mass, the GW strength could be an order of magnitude different, and the frequency band could be two times different for and . Moreover, the SGWB from Pop III BHs with could be detected by the Laser Interferometer Space Antenna for one year of observation, but it cannot be detected for those with .
How SFRIs vary with methods of sampling the IMF and duplicity

Using our new Binary Population and Spectral Synthesis (BPASS) code we explore the affect of binary populations on the integrated spectra of galaxies. We also explore the interplay of binary populations and a varying maximum stellar mass. We compare our synthetic populations to observations of H$\alpha$ emission from isolated clusters and H$\alpha$ and FUV observations of galaxies. We find that observations tend to favour a pure stochastic sampling of the initial mass function although the evidence is not significant. We also find that binaries make a stellar population less susceptible to the stochastic effects of filling the IMF. Therefore making it more difficult to determine if there is a variable maximum stellar mass.
Intervalley dark trion states with spin lifetimes of 150 ns in WSe 2

We demonstrate long trion spin lifetimes in a WSe$_2$ monolayer of up to 150 ns at 5 K. Applying a transverse magnetic field in time-resolved Kerr-rotation measurements reveals a complex composition of the spin signal of up to four distinct components. The Kerr rotation signal can be well described by a model which includes inhomogeneous spin dephasing and by setting the trion spin lifetimes to the measured excitonic recombination times extracted from time-resolved reflectivity measurements. We observe a continuous shift of the Kerr resonance with the probe energy, which can be explained by an adsorbate-induced, inhomogeneous potential landscape of the WSe$_2$ flake. A further indication of extrinsic effects on the spin dynamics is given by a change of both the trion spin lifetime and the distribution of g-factors over time. Finally, we detect a Kerr rotation signal from the trion's higher-energy triplet state when the lower-energy singlet state is optically pumped by circularly polarized light. We explain this by the formation of dark trion states, which are also responsible for the observed long trion spin lifetimes.
Hadron physics at KLOE and KLOE-2

The KLOE Collaboration completed the full data taking on March 2006, acquiring 2.5 fb ^ -1 at the peak of the \phi and other 240 pb ^ -1 off-peak. A new Collaboration is working on a new project, called KLOE-2, to refine and extend the KLOE physics program. We present here some preliminary and published results from the KLOE Collaboration on the pseudoscalar \eta meson and the study of \gamma \gamma processes, that are among the main points of the KLOE-2 physics program.
The Absorption and Emission Kinematics in the z = 0.7450 Mg II Absorber toward Q1331+17

We present a comparative analysis of the galaxy emission and quasar (QSO) absorption kinematics of a zabs ~ 0.7450 Mg II system and its candidate absorbing galaxy (G5) located 3. ″86 (28.3 h kpc) from the QSO. We have obtained a spectrum of the galaxy candidate, previously identified as a luminous edge-on disk, and detect the [O II] λ3727 doublet at a systemic redshift of zsys = 0.7450. From slit spectroscopy of this galaxy, we find vrot ≳ 210 km s-1, possibly as large as 350 km s-1. Plotted on the same velocity scale, the systemic redshift of the galaxy coincides with the center of the absorption system, although the absorption components span more than 100 km s-1 in either direction. However, once the sense of the rotation is taken into account, there is no absorbing gas at the projected velocity of the disk rotation curve. This implies incompatibility with a simple disk scenario. Moreover, a reanalysis of archival Hubble Space Telescope (HST) data reveals that the galaxy is only 0.3L*, considerably less luminous than previously reported in the literature. This is incompatible with the established Tully-Fisher relation at this redshift, unless approximately 2 mag of total extinction is invoked. Careful inspection of the archival HST data reveals that G5 may well be composed of two galaxies, although the quality of the data does not permit a detailed investigation of this. This possibility is further supported by the identification of a second faint emission line at λobs = 5674 Å, whose distinct spatial and velocity profiles indicate that it arises in a different galaxy at a different redshift. Analysis of the absorption lines shows evidence for superbubbles in the interstellar medium of the absorbing galaxy, based on the striking symmetry between components and large Mg I/Mg II and Mg I/Fe II ratios, indicative of large densities. The large velocity separations between line pairings, Δv ~ 150 km s-1, indicate that these bubbles may be powered by OB associations comparable to the largest observed at z = 0 and that the gas is probably enriched to at least 1/10 solar metallicity. This is consistent with observations at low redshift that extended Mg II halos are often seen in galaxies that contain disturbed gas. Superbubbles may also explain why the absorber has a relatively large Mg II equivalent width relative to the luminosity of the associated galaxy (or galaxies).
A propeller scenario for the gamma-ray emission of low-mass X-ray binaries: the case of XSS J12270−4859

XSS J12270‐4859 is the only low mass X-ray binary (LMXB) witha proposed persistent gamma-ray counterpart in the Fermi-LAT domain, 2FGL 1227.7‐4853. Here, we present the results of the analysis of recent INTEGRAL observations, aimed at assessing the long-term variability of the hard X-ray emission, and thus the stabili ty of the accretion state. We confirm that the source behaves as a persistent hard X-ray emitter between 2003 and 2012. We propose that XSS J12270‐4859 hosts a neutron star in a propeller state, a state we investigate in detail, developing a theoretical model to reproduce the associated X-ray and gamma-ray properties. This model can be understood as being of a more general nature, representing a viable alternative by which LMXBs can appear as gamma-ray sources. In particular, this may apply to the case of millisecond pulsars performing a transition fro m a state powered by the rotation of their magnetic field, to a state powered by matter in-fall, su ch as that recently observed from the transitional pulsar PSR J1023+0038. While the surface magnetic field of a typical NS in a LMXB is lower by more than four orders of magnitude than the much more intense fields of neutron stars accompanying high-mass binaries, the radius at which the matter in-flow is truncated in a NS-LMXB system is much lower. The magnetic field at the magnetospheric interface is then orders of magnitude larger at this interface , and as consequence, so is the power to accelerate electrons. We demonstrate that the cooling of the accelerated electron population takes place mainly through synchrotron interaction with the magnetic field permeating the interface, and through inverse Compton losses due to the interaction between the electrons and the synchrotron photons they emit. We found that self-synchrotron Compton processes can explain the high energy phenomenology of XSS J12270‐4859.
SURFACE LAYER ACCRETION IN CONVENTIONAL AND TRANSITIONAL DISKS DRIVEN BY FAR-ULTRAVIOLET IONIZATION

Whether protoplanetary disks accrete at observationally significant rates by the magnetorotational instability (MRI) depends on how well ionized they are. Disk surface layers ionized by stellar X-rays are susceptible to charge neutralization by small condensates, ranging from ∼0.01 μm sized grains to angstrom-sized polycyclic aromatic hydrocarbons (PAHs). Ion densities in X-ray-irradiated surfaces are so low that ambipolar diffusion weakens the MRI. Here we show that ionization by stellar far-ultraviolet (FUV) radiation enables full-blown MRI turbulence in disk surface layers. Far-UV ionization of atomic carbon and sulfur produces a plasma so dense that it is immune to ion recombination on grains and PAHs. The FUV-ionized layer, of thickness 0.01–0.1 g cm−2, behaves in the ideal magnetohydrodynamic limit and can accrete at observationally significant rates at radii ≳ 1–10 AU. Surface layer accretion driven by FUV ionization can reproduce the trend of increasing accretion rate with increasing hole size seen in transitional disks. At radii ≲1–10 AU, FUV-ionized surface layers cannot sustain the accretion rates generated at larger distance, and unless turbulent mixing of plasma can thicken the MRI-active layer, an additional means of transport is needed. In the case of transitional disks, it could be provided by planets.
Arrhythmogenic effect of extracellular K-depletion is preventedby the transverse-axial tubular system in a ventricular cardiaccell model

In this work, we studied the role of the transverse-axial tubular system (TAT-system) in arrythmogenesis of ventricular cardiac cells under conditions of simulated hypokalaemia (low [K]e). We used the model of a mammalian ventricular myocyte that integrated the quantitative description of electrical activity of surface and tubular membranes and dynamic changes in intracellular ion concentrations. To maintain potassium homeostasis, an energy-dependent K+ extrusion pump was incorporated into the model. According to predictions provided by the model, the TAT-system protects the cell against arrhythmogenesis due to the enhancement of a potassium concentration gradient between tubular and extracellular spaces at low levels of [K]e. The energy-dependent K extrusion pump maintains tubular [K] at a level higher than the overall [K]e. This makes the activation of tubular K-conductances responsible for action potential repolarisation and resting voltage.
Mutually unbiased bases with free parameters

We present a systematic method to introduce free parameters in sets of mutually unbiased bases. In particular, we demonstrate that any set of m real mutually unbiased bases in dimension N>2 admits the introduction of (m-1)N/2 free parameters which cannot be absorbed by a global unitary operation. As consequence, there are m=k+1 mutually unbiased bases in every dimension N=k^2 with k^3/2 free parameters, where k is even. We construct the maximal set of triplets of mutually unbiased bases for two-qubits systems and triplets, quadruplets and quintuplets of mutually unbiased bases with free parameters for three-qubits systems. Furthermore, we study the richness of the entanglement structure of such bases and we provide the quantum circuits required to implement all these bases with free parameters in the laboratory. Finally, we find the upper bound for the maximal number of real and complex mutually unbiased bases existing in every dimension. This proof is simple, short and it considers basic matrix algebra.
Prospects for the Determination of Higgs Boson Properties at the LHC

The prospects for the determination of the properties of a hypothetical boson discovered at the Large Hadron Collider using measurements to be performed with the ATLAS and CMS detectors are summarized. The properties that are discussed are the mass of the boson, its width, the strength of its couplings to fermions, the strength and structure of its couplings to gauge bosons and its spin and CP quantum numbers.
Sentinel-6 MF Poseidon-4 Radar Altimeter In-Flight Calibration and Performances Monitoring

Poseidon-4 is a dual-frequency redundant radar altimeter, embarked onboard the Sentinel-6 Michael Freilich (MF) European Commission Copernicus Programme satellite. In this article, we assess Poseidon-4 main instrumental improvements and performances with the presentation of the more important outcomes from the in-flight internal calibration modes and an external calibration analysis over a transponder. The instrumental performances of the radar altimeter are excellent for both radar chain sides: Poseidon-4 delivers a range/azimuth instrument impulse response (IR) with the highest quality and fidelity in the era of space-borne radar altimetry, and its thermal noise response is almost just random noise. A power decay of the level of the transmitted power in the Ku-band has been detected both for the nominal and redundant sides, which is larger than expected, though it will not violate the requirement of the minimum signal-to-noise ratio over the ocean at the end of the satellite design lifetime. The innovative CAL1 ECHO CAL calibration mode allows for very precisely characterizing the sensitivity of the instrument IR to the in-orbit temperature variations and, thus, correcting for it in the science data as standard practice.
Symmetry Orbits of Supergravity Black Holes - In Honor of Andrei Slavnov's 75th Birthday

Black hole solutions of supergravity theories form families that realizing the deep nonlinear "duality" symmetries of these theories. They form orbits under the action of these symmetry groups, with extremal (i.e. BPS) solutions at the limits of such orbits. An important technique in the analysis of such solution families employs timelike dimensional reduction and exchanges the stationary black-hole problem for a nonlinear sigma-model problem. Families of extremal or BPS solutions are characterized by nilpotent orbits under the duality symmetries, based upon a tri-graded or penta-graded decomposition of the corresponding duality-group algebra.
Why Galaxies Care about Post-AGB stars

Post-AGB stars evolve on a very fast track and hence not many are known. Their spectral properties make them, in principle, ideal objects to test our theories on the late phases of stellar evolution. This has, however, proven much more difficult than anticipated, mainly because the morphological, dynamical and chemical diversity in Galactic post-AGB stars is very large indeed. Here I focus on recent results and touch upon the bright near future of post-AGB research.
Squeezed Light

The squeezed state of the electromagnetic ﬁeld can be generated in many nonlinear optical processes and ﬁnds a wide range of applications in quantum information processing and quantum metrology. This article reviews the basic properties of single-and dual-mode squeezed light states, methods of their preparation and detection, as well as their quantum technology applications.