Miracle-dz/UniFAR-FTUs huggingface dataset:
Radiofrequency driving of coherent electron spin dynamics in 
n
-GaAs detected by Faraday rotation

We suggest a new pump-probe method for studying semiconductor spin dynamics based on pumping of carrier spins by a pulse of oscillating radiofrequency (rf) magnetic field and probing by measuring the Faraday rotation of a short laser pulse. We demonstrate this technique on $n$-GaAs and observe the onset and decay of coherent spin precession during and after the course of rf pulse excitation. We show that the rf field resonantly addresses the electron spins with Larmor frequencies close to that of the rf field. This opens the opportunity to determine the homogeneous spin coherence time $T_2$, that is inaccessible directly in standard all-optical pump-probe experiments.
Extremely metal-deficient red giants. II. Chemical abundances in 21 halo giants

Using a model-atmosphere analysis, we have determined chemical abundances in 21 red giants of the galactic halo. Nine new field stars from Bond's recent objective-prism survey, along with the well-known halo giant HD 122563, were analyzed on new high-dispersion spectrograms obtained at Palomar, Mount Wilson, and Cerro Tololo. Five giants in the globular cluster M13, three in M3, and three additional field stars were also analyzed using previously published equivalent-widths, providing a total sample of 21 halo giants analyzed in a homogeneous manner.
Searching for long-lived particles beyond the Standard Model at the Large Hadron Collider

Particles beyond the Standard Model (SM) can generically have lifetimes that are long compared to SM particles at the weak scale. When produced at experiments such as the Large Hadron Collider (LHC) at CERN, these long-lived particles (LLPs) can decay far from the interaction vertex of the primary proton-proton collision. Such LLP signatures are distinct from those of promptly decaying particles that are targeted by the majority of searches for new physics at the LHC, often requiring customized techniques to identify, for example, significantly displaced decay vertices, tracks with atypical properties, and short track segments. Given their non-standard nature, a comprehensive overview of LLP signatures at the LHC is beneficial to ensure that possible avenues of the discovery of new physics are not overlooked. Here we report on the joint work of a community of theorists and experimentalists with the ATLAS, CMS, and LHCb experiments --- as well as those working on dedicated experiments such as MoEDAL, milliQan, MATHUSLA, CODEX-b, and FASER --- to survey the current state of LLP searches at the LHC, and to chart a path for the development of LLP searches into the future, both in the upcoming Run 3 and at the High-Luminosity LHC. The work is organized around the current and future potential capabilities of LHC experiments to generally discover new LLPs, and takes a signature-based approach to surveying classes of models that give rise to LLPs rather than emphasizing any particular theory motivation. We develop a set of simplified models; assess the coverage of current searches; document known, often unexpected backgrounds; explore the capabilities of proposed detector upgrades; provide recommendations for the presentation of search results; and look towards the newest frontiers, namely high-multiplicity "dark showers", highlighting opportunities for expanding the LHC reach for these signals.
Noise in ML-EM reconstruction of SPECT images with attenuation correction

The authors derive a closed form expression for the pixel variance in the iterative ML-EM reconstruction of a uniform circular source embedded in a uniformly attenuating circular object. The derivation includes both the photon noise in the projection data and the noise in the attenuation map used for attenuation correction. The variance is found to increase with the number of iterations, but converges to a finite value. The noise to signal ratio at convergence is the sum of two terms which correspond to the contributions from the photon noise in the projection data and the attenuation map noise. The noise component due to the photon noise varies inversely with the total number of detected counts in the projection data. The relative variance at infinite iterations is similar in magnitude to that obtained for the filtered backprojection algorithm. The component due to attenuation map noise is proportional to the relative variance of the attenuation coefficient in the attenuation map. These observations are consistent with the results of the authors' previous computer simulation and experimental studies.
Global Simulations of the Inner Regions of Protoplanetary Disks with Comprehensive Disk Microphysics

The gas dynamics of weakly ionized protoplanetary disks (PPDs) are largely governed by the coupling between gas and magnetic fields, described by three non-ideal magnetohydrodynamical (MHD) effects (Ohmic, Hall, ambipolar). Previous local simulations incorporating these processes have revealed that the inner regions of PPDs are largely laminar and accompanied by wind-driven accretion. We conduct 2D axisymmetric, fully global MHD simulations of these regions (∼1–20 au), taking into account all non-ideal MHD effects, with tabulated diffusion coefficients and approximate treatment of external ionization and heating. With the net vertical field aligned with disk rotation, the Hall-shear instability strongly amplifies horizontal magnetic field, making the overall dynamics dependent on initial field configuration. Following disk formation, the disk likely relaxes into an inner zone characterized by asymmetric field configuration across the midplane, which smoothly transitions to a more symmetric outer zone. Angular momentum transport is driven by both MHD winds and laminar Maxwell stress, with both accretion and decretion flows present at different heights, and modestly asymmetric winds from the two disk sides. With anti-aligned field polarity, weakly magnetized disks settle into an asymmetric field configuration with supersonic accretion flow concentrated at one side of the disk surface, and highly asymmetric winds between the two disk sides. In all cases, the wind is magneto-thermal in nature, characterized by a mass loss rate exceeding the accretion rate. More strongly magnetized disks give more symmetric field configuration and flow structures. Deeper far-UV penetration leads to stronger and less stable outflows. Implications for observations and planet formation are also discussed.
Robopol: optical polarisation monitoring of blazars

The RoboPol program has been monitoring the R-band linear polarisation parameters of an unbiased sample of 60 gamma-ray-loud blazars and a “control” sample of 15 gamma-ray-quite ones. The prime drive for the program has been the systematic study of the temporal behaviour of the optical polarisation and particularly the potential association of smooth and long rotations of the polarisation angle with flaring activity at high energies. Here we present the program and discuss a list of selected topics from our studies of the first three observing seasons (2013–2015) both in the angle and in the amplitude domain.
Accreting magnetars: linking ultraluminous X-ray pulsars and the slow pulsation X-ray pulsars

Possible manifestations of accreting magnetars are discussed. It is shown that the four ultra-luminous X-ray pulsars can be understood in the accreting low magnetic field magnetar scenario. The NGC300 ULX1 pulsar may have a higher dipole magnetic field than other sources. General constraint on their mass accretion rate confirmed their super-Eddington nature. Lower limits on their beaming factor are obtained. They do not seem to have strong beaming. The duty cycle of the ULX burst state can also be constrained by their timing observations. ULX pulsars may be in accretion equilibrium in the long run. During the outburst, they will spin up, and run from the previous equilibrium state to the new equilibrium state. It is proposed that the slowest puslation X-ray pulsar AX J1910.7+0917 may be an accreting magnetar with a low mass accretion rate. ULX pulsars, slow pulsation X-ray pulsars may all be accreting magnetars with different accretion rates. Seven possible signatures of an accreting magnetar are summarized.
Observation of Floquet band topology change in driven ultracold Fermi gases

Lianghui Huang, Peng Peng, Donghao Li, Zengming Meng, Liangchao Chen, Chunlei Qu, Pengjun Wang, Chuanwei Zhang3,∗ and Jing Zhang1,5† State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Opto-Electronics, Shanxi University, Taiyuan 030006, P.R. China Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, P.R. China Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, USA INO-CNR BEC Center and Dipartimento di Fisica, Università di Trento, 38123 Povo, Italy and Synergetic Innovation Center of Quantum Information and Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
U-duality Invariant Quantum Entropy from Sums of Kloosterman Sums

U-duality plays a special role in the study of the microscopic degrees of freedom of supersymmetric black holes. To be consistent with duality, the black hole quantum degeneracy must obey special arithmetic properties, which are non-perturbative in nature. In this work, we study these properties from a holographic point of view, establishing a connection between arithmetic properties of Kloosterman sums and quantum gravity in $\text{AdS}_2$ space. To this end, we consider the entropy of black holes that carry non-primitive charges, in both $\mathcal{N}=8$ and $\mathcal{N}=4$ four dimensional compactifications; our analysis includes all the perturbative and non-perturbative bulk quantum corrections. The key result relies on special arithmetic properties of generalized Kloosterman sums that we develop. These are a generalization of the known Selberg identity of classical Kloosterman sums. In both the $\mathcal{N}=8$ and $\mathcal{N}=4$ examples, we recover, from the bulk quantum gravity, the non-primitive answer which is a sum over the primitive degeneracies, depending non-trivially on the discrete duality invariants. In particular, for the $\mathcal{N}=4$ case we show that the quantum gravity answer reproduces the dependence on the torsion invariant $I=\text{gcd}(Q\wedge P)$, in agreement with the microscopic formulas. For the $\mathcal{N}=8$ case, we solve a puzzle related to U-duality invariance of the supergravity answer and the corresponding one-eighth BPS degeneracy.
Simulating Quantum Circuits by Shuffling Paulis

Verification of NISQ era quantum devices demands fast classical simulation of large noisy quantum circuits. We present an algorithm based on the stabilizer formalism that can efficiently simulate noisy stabilizer circuits. Additionally, the protocol can efficiently simulate a large set of multi-qubit mixed states that are not mixtures of stabilizer states. The existence of these 'bound states' was previously only known for odd-dimensional systems like qutrits. The algorithm also has the favorable property that circuits with depolarizing noise are simulated much faster than unitary circuits. This work builds upon a similar algorithm by Bennink et al. (Phys. Rev. A 95, 062337) and utilizes a framework by Pashayan et al. (Phys. Rev. Lett. 115, 070501).
The equivalence of fluctuation scale dependence and autocorrelations

We define optimal per-particle fluctuation and correlation measures, relate fluctuations and correlations through an integral equation and show how to invert that equation to obtain precise autocorrelations from fluctuation scale dependence. We test the precision of the inversion with Monte Carlo data and compare autocorrelations to conditional distributions conventionally used to study high-pt jet structure.
Potential of Microalgae Extracts for Food and Feed Supplementation—A Promising Source of Antioxidant and Anti-Inflammatory Compounds

Microalgae are known producers of antioxidant and anti-inflammatory compounds, making them natural alternatives to be used as food and feed functional ingredients. This study aimed to valorise biomass and exploit new applications and commercial value for four commercially available microalgae: Isochrysis galbana, Nannochloropsis sp. , Tetraselmis sp. , and Phaeodactylum tricornutum. For that, five extracts were obtained: acetone (A), ethanol (E), water (W), ethanol:water (EW). The antioxidant capacity (ABTS•+/DPPH•/•NO/O2•−/ORAC-FL) and anti-inflammatory capacity (HBRC/COX-2) of the extracts were screened. The general biochemical composition (carbohydrates, soluble proteins, and lipids) and the main groups of bioactive compounds (carotenoids, phenolic compounds, and peptides) of extracts were quantified. The results of antioxidant assays revealed the potential of some microalgae extracts: in ABTS•+, Nannochloropsis sp. E and Tetraselmis sp. A, E, and P; in DPPH•, Tetraselmis sp. A and E; in •NO, P. tricornutum E and EW; in O2•−, Tetraselmis sp. W; and in ORAC-FL, I. galbana EW and P. tricornutum EW. Concerning anti-inflammatory capacity, P. tricornutum EW and Tetraselmis sp. W showed a promising HBRC protective effect and COX-2 inhibition. Hence, Tetraselmis sp. and P. tricornutum extracts seem to have potential to be incorporated as feed and food functional ingredients and preservatives.
ANALYSIS OF HOPF/HOPF BIFURCATIONS IN NONLOCAL HYPERBOLIC MODELS FOR SELF-ORGANISED AGGREGATIONS

The modelling and investigation of complex spatial and spatio-temporal patterns exhibited by a various self-organised biological aggregations has become one of the most rapidly-expanding research areas. Generally, the majority of the studies in this area either try to reproduce numerically the observed patterns, or use existence results to prove analytically that the models can exhibit certain types of patterns. Here, we focus on a class of nonlocal hyperbolic models for self-organised movement and aggregations, and investigate the bifurcation of some spatial and spatio-temporal patterns observed numerically near a codimension-2 Hopf/Hopf bifurcation point. Using weakly nonlinear analysis and the symmetry of the model, we identify analytically all types of solutions that can exist in the neighbourhood of this bifurcation point. We also discuss the stability of these solutions, and the implication of these stability results on the observed numerical patterns.
Calculations of atomic processes in Fe XVII

We have made a synoptic study of the neon-like ion Fe XVII in order to improve our knowledge of its line production in high-temperature, low-density plasmas. We have computed the following: (1) distorted wave, electron collision strengths from the ground level to all 88 levels with one n = 3 or n = 4 electron; (2) a complete cascade matrix; (3) the contribution of resonances to the n = 3 level population rates; and (4) the resulting X-ray and EUV line emission coefficients as functions of temperature between T = 10/sup 5.6/ and T = 10/sup 8.4/ K. From these results the spectrum of Fe XVII can be calculated in the low density limit.
Health in digital environment

Office work is associated with movement restrictions, muscle stress, burnout and other risk factors that negatively affect the health of working - age people. The coronavirus epidemic has changed the labor market: neither employers nor employees were prepared to tackle the challenges of moving to remote work. Therefore, search for solutions to preserve health of remote workers in the context of self-isolation and digital transformation is a priority medical and social task. Pilot research for examination of the office-workers state included interviews, psychological, neurological tests and methods of instrumental visualization. The aim of the study was to identify the signs of the emotional impact of remote work and develop exercises to prevent physical inactivity, as well as technologies for monitoring of individuals’ health. The survey revealed that 80% of office workers have stress and burnout in an epidemic situation, as well as a loss of interest in work and professional achievements. Burnout was accompanied with increased irritability, sleep disorders. Neurological examination revealed muscle spasms and “tunnel” neurovascular disorders in the cervical spine and postural displacement in all persons. Electrophysiological research indicated cerebral acidosis and brain hypoxia in 50% of examined individuals. The programs for postural correction and cerebral metabolism included special coordination and breathing exercises. Recommendations to healthy lifestyle and workplace reorganization were given to all persons. Digital transformation is a challenge that requires changes in legal, organizational, psychological and infrastructural approaches to preserve the health of remote workers in the new environment.
Highly ionized Fe K emission lines from the LINER galaxy M 81

We present spectral and timing results from a long (130 ks) XMM-Newton EPIC observation of the nucleus of the Seyfert/LINER galaxy M 81. During the observation the X-ray ﬂux varied by 20%, but there was no signiﬁcant change in spectral shape. The 2–10 keV spectrum is well described by a power law continuum and three narrow Fe K α emission lines at 6.4, 6.7 and 6.96 keV. The three emission lines have equivalent widths of 39 +13 − 12 , 47 +13 − 13 and 37 +15 − 15 eV respectively. The ratios of the three lines are thus more similar to those observed from the Galactic Centre region than to those typically observed from Seyfert galaxies. The high ionization lines most likely originate either from photoionized gas within 0.1 pc of the nucleus of M 81, or from a non-thermal distribution of cosmic-ray electrons interacting with the 0.2-0.6 keV thermal plasma which is found in the bulge of M 81.
Evolution with temperature of the magnetic polaron state in an antiferromagnetic chain with impurities

The thermal behavior of a one-dimensional antiferromagnetic chain doped by donor impurities was analyzed. The ground state of such a chain corresponds to the formation of a set of ferromagnetically correlated regions localized near impurities (bound magnetic polarons). At finite temperatures, the magnetic structure of the chain was calculated simultaneously with the wave function of a conduction electron bound by an impurity. The calculations were performed using an approximate variational method and a Monte Carlo simulation. Both these methods give similar results. The analysis of the temperature dependence of correlation functions for neighboring local spins demonstrated that the ferromagnetic correlations inside a magnetic polaron remain significant even above the N\'eel temperature ${T}_{N}$ implying rather high stability of the magnetic polaron state. In the case when the electron-impurity coupling energy $V$ is not too high (for $V$ lower than the electron hopping integral $t$), the magnetic polaron could be depinned from impurity retaining its magnetic structure. Such a depinning occurs at temperatures of the order of $V$. At even higher temperatures ($T\ensuremath{\sim}t$) magnetic polarons disappear and the chain becomes completely disordered.
Beliefs About Giving Across Contexts

A rich literature investigates prosocial behavior by exploiting a variety of methods, the validity of which has been debated. While this literature has compared behavior inside and outside of the laboratory, an open question is how participants view prosocial behavior across different contexts. This paper shows that donation decisions are consistently believed to be indicative of individuals’ prosociality—regardless of whether they are measured in a laboratory setting, field setting, or via surveys, and regardless of whether they involve hypothetical, small or large stakes. Our results lend credence to research across these different types of contexts. ∗Exley: clexley@hbs.edu, Harvard Business School; Pezzuto: jpezzuto@ucsd.edu, University of California San Diego; Serra-Garcia: mserragarcia@ucsd.edu, University of California San Diego. For very helpful feedback on this paper, we thank Tristan Gagnon-Bartsch, Laura Gee, Stephanie Heger, Daniel Navarro Martinez, Stephan Meier, Emma Ronzetti, and Robert Slonim. We also thank Stephan Meier for providing us data and code from his prior work. For funding, we thank Harvard Business School and University of California San Diego.
The Wide Field Infrared Survey Telescope: 100 Hubbles for the 2020s

The Wide Field Infrared Survey Telescope (WFIRST) is a 2.4m space telescope with a 0.281 deg^2 field of view for near-IR imaging and slitless spectroscopy and a coronagraph designed for > 10^8 starlight suppresion. As background information for Astro2020 white papers, this article summarizes the current design and anticipated performance of WFIRST. While WFIRST does not have the UV imaging/spectroscopic capabilities of the Hubble Space Telescope, for wide field near-IR surveys WFIRST is hundreds of times more efficient. Some of the most ambitious multi-cycle HST Treasury programs could be executed as routine General Observer (GO) programs on WFIRST. The large area and time-domain surveys planned for the cosmology and exoplanet microlensing programs will produce extraordinarily rich data sets that enable an enormous range of Archival Research (AR) investigations. Requirements for the coronagraph are defined based on its status as a technology demonstration, but its expected performance will enable unprecedented observations of nearby giant exoplanets and circumstellar disks. WFIRST is currently in the Preliminary Design and Technology Completion phase (Phase B), on schedule for launch in 2025, with several of its critical components already in production.
AI-Based Exhaust Gas Temperature Prediction for Trustworthy Safety-Critical Applications

Data-driven condition-based maintenance (CBM) and predictive maintenance (PdM) strategies have emerged over recent years and aim at minimizing the aviation maintenance costs and environmental impact by the diagnosis and prognosis of aircraft systems. As the use of data and relevant algorithms is essential to AI-based gas turbine diagnostics, there are different technical, operational, and regulatory challenges that need to be tackled in order for the aeronautical industry to be able to exploit their full potential. In this work, the machine learning (ML) method of the generalised additive model (GAM) is used in order to predict the evolution of an aero engine’s exhaust gas temperature (EGT). Three different continuous synthetic data sets developed by NASA are employed, known as New Commercial Modular Aero-Propulsion System Simulation (N-CMAPSS), with increasing complexity in engine deterioration. The results show that the GAM can be predict the evolution of the EGT with high accuracy when using several input features that resemble the types of physical sensors installed in aero gas turbines currently in operation. As the GAM offers good interpretability, this case study is used to discuss the different data attributes a data set needs to have in order to build trust and move towards certifiable models in the future.
Gaussian quantum channels beyond the Gaussian functional form: full characterization of the one-mode case

We study one-mode Gaussian quantum channels in continuous-variable systems by performing a black-box characterization using complete positivity and trace preserving conditions, and report the existence of two subsets that do not have a functional Gaussian form. Our study covers as particular limit the case of singular channels, thus connecting our results with their known classification scheme based on canonical forms. Our full characterization of Gaussian channels without Gaussian functional form is completed by showing how Gaussian states are transformed under these operations, and by deriving the conditions for the existence of master equations for the non-singular cases.