Miracle-dz/UniFAR-FTUs huggingface dataset:
Multiparty quantum protocols for assisted entanglement distillation

Quantum information theory is a multidisciplinary field whose objective is to understand what happens when information is stored in the state of a quantum system. Quantum mechanics provides us with a new resource, called quantum entanglement, which can be exploited to achieve novel tasks such as teleportation and superdense coding. Current technologies allow the transmission of entangled photon pairs across distances up to roughly 100 kilometers. For longer distances, noise arising from various sources degrade the transmission of entanglement to the point that it becomes impossible to use the entanglement as a resource for future tasks. A strategy for dealing with this difficulty is to employ quantum repeaters, stations intermediate between the sender and receiver which participate in the process of entanglement distillation, thereby improving on what the sender and receiver could do on their own. In this work, we study entanglement distillation between two recipients sharing a mixed state and with the help of repeater stations. We extend the notion of entanglement of assistance to arbitrary states and give a protocol for extracting pure entanglement. We also study quantum communication protocols in a more general context. We give a new protocol for the task of multiparty state merging. The previous multiparty state merging protocol required the use of time-sharing. Our protocol does not require time-sharing for distributed compression of two senders. In the one-shot regime, we achieve multiparty state merging with entanglement costs not restricted to corner points of the entanglement cost region. Our analysis of the entanglement cost is performed using (smooth) min- and max-entropies. We illustrate the benefits of our approach by looking at different examples.
Schrödinger quantization of linearly polarized Gowdy \protect\bb{S}^{1}\times\protect\bb{S}^{2} and \protect\bb{S}^{3} models coupled to massless scalar fields

In this paper, we will construct the Schrodinger representation for the linearly polarized Gowdy and models coupled to massless scalar fields. Here the quantum states belong to a L2-space for a suitable quantum configuration space endowed with a Gaussian measure, whose support is analyzed. This study completes the quantization of these systems previously performed in the Fock scheme, and provides a specially useful framework to address physically relevant questions.
Parallax measurements of cool brown dwarfs

Landessternwarte Konigstuhl 12, D-69117 Heidelberg, Germanye-mail: sreffert@lsw.uni-heidelberg.deReceived 18 April 2013; accepted October 2013ABSTRACTContext. Accurate parallax measurements allow us to determine physical properties of brown dwarfs and help usconstrain evolutionary and atmospheric models, break age-mass degeneracy, and reveal unresolved binaries.Aims. We measured absolute trigonometric parallaxes and proper motions of six cool brown dwarfs using backgroundgalaxies to establish an absolute reference frame. We derive the absolute J-band magnitude. The six T brown dwarfsin our sample have spectral types between T2.5 and T8 and magnitudes between 13.9 and 18.0 in 2MASS (Two MicronAll Sky Survey) with photometric distances below 25 pc.Methods. The observations were taken in the J-band with the Omega-2000 camera on the 3.5 m telescope at Calar Altoduring a time period of 27 months between March 2011 and June 2013. The number of epochs varied between 11 and12 depending on the object. The reduction of the astrometric measurements was carried out with respect to the ﬁeldstars. The relative parallax and proper motions were transformed into absolute measurements using the backgroundgalaxies in our ﬁelds. Results. We obtained absolute parallaxes for our six brown dwarfs with a precision between 3 and 6 mas. We comparedour results in a color-magnitude diagram with other brown dwarfs with determined parallax and with the BT-Settl2012 atmospheric models. For four of the six targets, we found a good agreement in luminosity with objects of similarspectral types. We obtained an improved accuracy in the parallaxes and proper motions in comparison to previousworks. The object 2MASS J11061197+2754225 is more than 1 mag overluminous in all bands, which point to binarityor high order multiplicity.Key words.
Opera Highlights

The OPERA experiment is a long baseline neutrino oscillation experiment aimed at observing the ν µ → ν τ neutrino oscillation in the CERN neutrino to Gran Sasso beamline in the appearance mode by detecting the τ - decay. Here I will summarize the results from the run years 2008-10 with an update on observed rare decay topologies and the results of the neutrino velocity measurements.
Galaxy rotation curves and nonextensive statistics

We investigate the influence of the nonextensive q-statistics and kinetic theory on galactic scales through the analysis of a devised sample of Spiral Rotation Curves. Largely supported by recent developments on the foundations of statistical mechanics and a plethora of astrophysical applications, the theory also provides an alternative interpretation to the empirical cored dark matter profiles observed in galaxies. We show that the observations could well be fitted with reasonable values for the mass model parameters, encouraging further investigation into q-statistcs on the distribution of dark matter from both observational and theoretical points of view.
Asymmetric supernova remnants generated by Galactic, massive runaway stars

After the death of a runaway massive star, its supernova shock wave interacts with the bow shocks produced by its defunct progenitor, and may lose energy, momentum, and its spherical symmetry before expanding into the local interstellar medium (ISM). We investigate whether the initial mass and space velocity of these progenitors can be associated with asymmetric supernova remnants. We run hydrodynamical models of supernovae exploding in the pre-shaped medium of moving Galactic core-collapse progenitors. We find that bow shocks that accumulate more than about1.5M⊙ generate asymmetric remnants. The shock wave first collides with these bow shocks 160 − 750yr after the supernova, and the collision lasts until 830 − 4900yr. The shock wave is then located 1.35 − 5pc from the center of the explosion, and it expands freely into the ISM, whereas in the opposite direction it is channelled into the region of undisturbed wind material. This applies to an initially 20M⊙ progenitor moving with velocity 20kms −1 and to our initially 40M⊙ progenitor. These remnants generate mixing of ISM gas, stellar wind and supernova ejecta that is particularly important upstream from the center of the explosion. Their lightcurves are dominated by emission from optically-thin cooling and by X-ray emission of the shocked ISM gas. We find th at these remnants are likely to be observed in the [OIII] �5007 spectral line emission or in the soft energy-band of X-rays. Finally, we discuss our results in the context of observed Galactic supernova remnants such as 3C391 and the Cygnus Loop.
The inherently absent 2-dimensional electron gas in ultra-pure GaN/AlGaN heterostructures

Gallium nitride (GaN) has emerged as an essential semiconductor material for energy-efficient lighting and electronic applications owing to its large direct bandgap of 3.4 eV. Present GaN/AlGaN heterostructures seemingly feature an inherently existing, highly-mobile 2-dimensional electron gas (2DEG), which results in normally-on transistor characteristics. Here we report on an ultra-pure GaN/AlGaN layer stack grown by molecular beam epitaxy, in which such a 2DEG is absent at 300 K in the dark, a property previously not demonstrated. Illumination with ultra-violet light however, generates a 2DEG at the GaN/AlGaN interface and the heterostructure becomes electrically conductive. At temperatures below 150 K this photo-conductivity is persistent with an insignificant dependence of the 2D channel density on the optical excitation power. Residual donor impurity concentrations below 10$^{17}$ cm$^{-3}$ in the GaN/AlGaN layer stack are one necessity for our observations. Fabricated transistors manifest that these characteristics enable a future generation of normally-off as well as light-sensitive GaN-based device concepts.
Analysis of Hierarchical Ensemble Kalman Inversion

We discuss properties of hierarchical Bayesian inversion through the ensemble Kalman filter (EnKF). Our focus will be primarily on deriving continuous-time limits for hierarchical inversion in the linear case. An important characteristic of the EnKF for inverse problems is that the updated particles are preserved by the linear span of the initial ensemble. By incorporating certain hierarchical approaches we show that we can break away from the induced subspace property. We further consider a number of variants of the EnKF such as covariance inflation and localization, where we derive their continuous-time limits. We verify these results with various numerical experiments through a linear elliptic partial differential equation.
Model-independent extraction of the proton charge radius from electron scattering

Constraints from analyticity are combined with experimental electron-proton scattering data to determine the proton charge radius. In contrast to previous determinations, we provide a systematic procedure for analyzing arbitrary data without model-dependent assumptions on the form-factor shape. We also investigate the impact of including electron-neutron scattering data, and {pi}{pi}{yields}NN data. Using representative data sets we find r{sub E}{sup p}=0.870{+-}0.023{+-}0.012 fm using just proton scattering data; r{sub E}{sup p}=0.880{sub -0.020}{sup +0.017{+-}}0.007 fm adding neutron data; and r{sub E}{sup p}=0.871{+-}0.009{+-}0.002{+-}0.002 fm adding {pi}{pi} data. The analysis can be readily extended to other nucleon form factors and derived observables.
DETERMINATION OF SUB-RESOLUTION STRUCTURE OF A JET BY SOLAR MAGNETOSEISMOLOGY

A thin dark thread is observed in a UV/EUV solar jet in the 171 Å, 193 Å, and 211 Å, and partially in 304 Å. The dark thread appears to originate in the chromosphere but its temperature does not appear to lie within the passbands of the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory. We therefore implement solar magnetoseismology to estimate the plasma parameters of the dark thread. A propagating kink (transverse) wave is observed to travel along the dark thread. The wave is tracked over a range of ∼7000 km by placing multiple slits along the axis of the dark thread. The phase speed and amplitude of the wave are estimated and magnetoseismological theory is employed to determine the plasma parameters. We are able to estimate the plasma temperature, density gradient, magnetic field gradient, and sub-resolution expansion of the dark thread. The dark thread is found to be cool, T ≲ 3 × 104, with both strong density and magnetic field gradients. The expansion of the flux tube along its length is ∼300–400 km.
Covert Quantum Internet

We apply covert quantum communication based on entanglement generated from the Minkowski vacuum to the setting of quantum computation and quantum networks. Our approach hides the generation and distribution of entanglement in quantum networks by taking advantage of relativistic quantum effects. We devise a suite of covert quantum teleportation protocols that utilize the shared entanglement, local operations, and covert classical communication to transfer or process quantum information in stealth. As an application of our covert suite, we construct two prominent examples of measurement-based quantum computation, namely the teleportation-based quantum computer and the one-way quantum computer. In the latter case we explore the covert generation of graph states, and subsequently outline a protocol for the covert implementation of universal blind quantum computation.
The First Hours of the GW170817 Kilonova and the Importance of Early Optical and Ultraviolet Observations for Constraining Emission Models

The kilonova associated with GW170817 displayed early blue emission, which has been interpreted as a signature of either radioactive decay in low-opacity ejecta, relativistic boosting of radioactive decay in high-velocity ejecta, the cooling of material heated by a wind or by a “cocoon” surrounding a jet, or a combination thereof. Distinguishing between these mechanisms is important for constraining the ejecta components and their parameters, which tie directly into the physics we can learn from these events. I compile published ultraviolet, optical, and infrared light curves of the GW170817 kilonova and examine whether the combined data set can be used to distinguish between early-emission models. The combined optical data show an early rise consistent with radioactive decay of low-opacity ejecta as the main emission source, but the subsequent decline is fit well by all models. A lack of constraints on the ultraviolet flux during the first few hours after discovery allows for both radioactive decay and other cooling mechanisms to explain the early bolometric light curve. This analysis demonstrates that early (few hours after merger) high-cadence optical and ultraviolet observations will be critical for determining the source of blue emission in future kilonovae.
Effect of planting densities on grain filling and kernel dehydration of maize (Zea mays)

Maize (Zea mays L.) yield is greatly affected by the environmental and cultivate pattern. Grain filling and dehydration play important roles in maize grain dry mass accumulation and are important biological processes in maize growth and development. Four maize cultivars were planted at Hebei province with planting densities of 60000 and 75000 plants/ha during 2017-18. The kernel fresh weight and dry weight of four cultivars were measured at 15, 22, 29, 36, 43, 50 and 57 days after pollination of two planting densities. Logistic model was used to estimate the grain filling process in different environments. The results showed that the maximum filling rates of all cultivars under two planting densities were attained at about 25 days after pollination. The grain filling period was longer under the planting density of 60000 plants/ha. Meanwhile, the grain dehydration was slower. With the increased of planting density, 100-grain weight of per plant decreased while the yield increased. The higher yield was contributed by the larger numbers of plants. It indicated that suitable higher planting density will enhance the yield of maize. Bract, cob and grain water content were significantly correlated. This study indicated a negative effect of dense planting on grain filling.
Is there evidence for anomalous dipole anisotropy in the large-scale structure?

We probe the anisotropy of the large-scale structure (LSS) with the WISE-2MASS catalogue. This analysis is performed by a directional comparison of the galaxy number counts through the entire celestial sphere once systematic effects, such as star-galaxy separation and foregrounds contamination, are properly taken into account. We find a maximal hemispherical asymmetry whose dipolar component is $A = 0.0507 \pm 0.0014$ toward the $(l,b) = (323^{\circ},-5^{\circ})$ direction, whose result is consistent with previous estimations of our proper motion in low and intermediate redshifts, as those carried out with Type Ia Supernovae and similar LSS catalogues. Furthermore, this dipole amplitude is statistically consistent ($p$-value = $0.061$) with mock catalogues simulated according to the expected $\Lambda$CDM matter density fluctuations, in addition to observational biases such as the incomplete celestial coverage and anisotropic sky exposure. Our results suggest, therefore, that there is no strong evidence for anomalous anisotropy in the LSS, given the limitations and systematics of current data, in the concordance model scenario.
Content Analysis or Thematic Analysis: Doctoral Students' Perceptions of Similarities and Differences

This paper is a review of content analysis or thematic analysis which is further explored though the lens of impressions of doctoral students who attended a presentation on the subject.The long tradition of quantitative research still dominates many university courses on research methodology and data analysis. During the 20th century the field of qualitative research has had a growing need for new analysis methods that accommodate qualitative data and two frequently used methods are content analysis and thematic analysis. They have several things in common and sometimes, they have been understood by researchers to be interchangeably. It has been argued by some researchers that conventional content analysis has really the same functional approach to analysing data as an inductive thematic analysis. This study reports on two webinars on qualitative analysis involving doctoral students and facilitated by the authors. The webinars presented, discussed content analysis and thematic analysis, and gathered participants’ reflections on these methods using a Padlet (padlet.com). The aim of the study was to analyse and describe doctoral students' perceptions of content analysis and thematic analysis. The data collected has been analysed using conventional content analysis applying an abductive coding approach. The study identifies several perceived similarities and differences between the two methods, but also opportunities and challenges for applying them. Findings highlight that the two methods are perceived to be applicable to different types of research. Furthermore, they offer similar challenges to the researcher including their potential for bias and could be considered a choice between an intuitive and a practical approach to analysis. Many of the identified perceptions can be related to previous literature on content analysis and thematic analysis. However, other perceptions seems to indicates a need for more thorough and nuanced discussions on methods for qualitative analysis. The study suggest that more efforts should be made to support doctoral students in attaining a nuanced understanding of qualitative methods for analysis.
FPGA Implementation of a Linearization System for Wideband Envelope Tracking Power Amplifiers

This article focuses on the implementation of a linearization system for envelope tracking (ET) power amplifiers (PAs) in field-programmable gate array (FPGA). The ET PA linearization system includes a slew-rate reduction envelope generator, a RF leakage cancellation system in the supply envelope path and a baseband <inline-formula> <tex-math notation="LaTeX">$I - Q$ </tex-math></inline-formula> digital predistorter (DPD). This work targets the implementation of an ET PA linearization system on a radio frequency system-on-chip (RFSoC) device running under a demanding baseband sampling frequency of 614.4 MHz, which allows handling communication signals with up to 200 MHz bandwidth, considering a DPD bandwidth expansion by <inline-formula> <tex-math notation="LaTeX">$3\times $ </tex-math></inline-formula>. The detail of the FPGA implementation is presented to illustrate the trade-off between hardware resources and linearization performance, i.e., adjacent channel power ratio (ACPR) and error vector magnitude (EVM), under different bit configurations for the arithmetic. The power consumption is also evaluated since it is another relevant performance indicator to be considered in the FPGA implementation of the linearization system.
Meterwavelength Single-pulse Polarimetric Emission Survey. III. The Phenomenon of Nulling in Pulsars

A detailed analysis of nulling was conducted for the pulsars studied in the Meterwavelength Single-pulse Polarimetric Emission Survey. We characterized nulling in 36 pulsars including 17 pulsars where the phenomenon was reported for the first time. The most dominant nulls lasted for a short duration, less than five periods. Longer duration nulls extending to hundreds of periods were also seen in some cases. A careful analysis showed the presence of periodicities in the transition from the null to the burst states in 11 pulsars. In our earlier work, fluctuation spectrum analysis showed multiple periodicities in 6 of these 11 pulsars. We demonstrate that the longer periodicity in each case was associated with nulling. The shorter periodicities usually originate from subpulse drifting. The nulling periodicities were more aligned with the periodic amplitude modulation, indicating a possible common origin for both. The most prevalent nulls last for a single period and can be potentially explained using random variations affecting the plasma processes in the pulsar magnetosphere. On the other hand, longer-duration nulls require changes in the pair-production processes, which need an external triggering mechanism for the changes. The presence of periodic nulling puts an added constraint on the triggering mechanism, which also needs to be periodic.
ROTATION AND WINDS OF EXOPLANET HD 189733 b MEASURED WITH HIGH-DISPERSION TRANSMISSION SPECTROSCOPY

Giant exoplanets orbiting very close to their parent star (hot Jupiters) are subject to tidal forces expected to synchronize their rotational and orbital periods on short timescales (tidal locking). However, spin rotation has never been measured directly for hot Jupiters. Furthermore, their atmospheres can show equatorial super-rotation via strong eastward jet streams, and/or high-altitude winds flowing from the day- to the night-side hemisphere. Planet rotation and atmospheric circulation broaden and distort the planet spectral lines to an extent that is detectable with measurements at high spectral resolution. We observed a transit of the hot Jupiter HD 189733 b around 2.3 μm and at a spectral resolution of R∼105 with CRIRES at the ESO Very Large Telescope. After correcting for the stellar absorption lines and their distortion during transit (the Rossiter–McLaughlin effect), we detect the absorption of carbon monoxide and water vapor in the planet transmission spectrum by cross-correlating with model spectra. The signal is maximized (7.6σ) for a planet rotational velocity of ( 3.4 − 2.1 + 1.3 ) ? > km s−1, corresponding to a rotational period of ( 1.7 − 0.4 + 2.9 ) ? > days. This is consistent with the planet orbital period of 2.2 days, and therefore with tidal locking. We find that the rotation of HD 189733 b is longer than 1 day (3σ). The data only marginally (1.5σ) prefer models with rotation versus models without rotation. We measure a small day- to night-side wind speed of ( − 1.7 − 1.2 + 1.1 ) ? > km s−1. Compared to the recent detection of sodium blueshifted by ( 8 ± 2 ) ? > km s−1, this likely implies a strong vertical wind shear between the pressures probed by near-infrared and optical transmission spectroscopy.
Hexagonal warping on optical conductivity of surface states in topological insulator Bi2Te3

ARPES studies of the protected surface states in the Topological Insulator $% Bi_{2}Te_{3}$ have revealed the existence of an important hexagonal warping term in its electronic band structure. This term distorts the shape of the Dirac cone from a circle at low energies to a snowflake shape at higher energies. We show that this implies important modifications of the interband optical transitions which no longer provide a constant universal background as seen in graphene. Rather the conductivity shows a quasilinear increase with a slightly concave upward bending as energy is increased. Its slope increases with increasing magnitude of the hexagonal distortion as does the magnitude of the jump at the interband onset. The energy dependence of the density of states is also modified and deviates downward from linear with increasing energy.