Miracle-dz/UniFAR-FTUs huggingface dataset:
INTERNAL γγ OPACITY IN ACTIVE GALACTIC NUCLEI AND THE CONSEQUENCES FOR THE TeV OBSERVATIONS OF M87 AND Cen A

Low-luminosity active galactic nuclei (LLAGNs) possess the characteristic features of more luminous active galactic nuclei (AGNs) but exhibit a much lower nuclear Hα luminosity (LHα < 1040 erg s−1) than their more luminous counterparts. M87 (NGC 4486) and Centaurus A (NGC 5128, Cen A) are well studied nearby LLAGNs. As an additional feature they show γ radiation up to TeV (1012 eV) energies, but the origin of this radiation has not been resolved. The coincident observation of a radio and TeV flare in M87 suggests that the TeV radiation is produced within around 50–100 gravitational radii of the central supermassive black hole, depending on the assumed value of the mass of the black hole. Strong radiation fields can be produced in the central region of an (LL)AGN, e.g., by the accretion flow around the black hole, the jet plasma, or stars closely orbiting the black hole. These radiation fields can lead to the absorption of emitted TeV photons, and, in fact, high optical depths of such fields can make TeV detection from inner regions impossible. In this paper, we consider the accretion flow around the black hole as the most prominent source for such a radiation field and we calculate accordingly the probability for absorption of TeV photons produced near the black holes in M87 and CenA assuming a low-luminosity Shakura–Sunyaev disk (SSD). We find that the results are very different between the two LLAGNs. While the inner region of M87 is transparent for TeV radiation up to ∼20 TeV within the allowed parameter range, the optical depth in Cen A is ≫1, leading to an absorption of TeV photons that might be produced near the central black hole. These results imply either that the TeV γ production sites and processes are different for both sources or that LLAGN black holes do not accrete (at least only) in the form of a low-luminosity SSD.
Accretion funnels onto weakly magnetized young stars

Aims. We re-examine the conditions required to steadily deviate an accretion flow from a circumstellar disc into a magnetospheric funnel flow onto a slow rotating young forming star. Methods. New analytical constraints on the formation of accretion funnels flows due to the presence of a dipolar stellar magnetic field disrupting the disc are derived. The Versatile Advection Code is used to confirm these constraints numerically. Axisymmetric MHD simulations are performed, where a stellar dipole field enters the resistive accretion disc, whose structure is self-consistently computed. Results. The analytical criterion derived allows to predict a priori the position of the truncation radius from a non perturbative accretion disc model. Accretion funnels are found to be robust features which occur below the co-rotation radius, where the stellar poloidal magnetic pressure becomes both at equipartition with the disc thermal pressure and is comparable to the disc poloidal ram pressure. We confirm the results of Romanova et al. (2002, ApJ, 578, 420) and find accretion funnels for stellar dipole fields as low as 140 G in the low accretion rate limit of 10(-9) M-circle dot yr(-1). With our present numerical setup with no disc magnetic field, we found no evidence of winds, neither disc driven nor X-winds, and the star is only spun up by its interaction with the disc. Conclusions. Weak dipole fields, similar in magnitude to those observed, lead to the development of accretion funnel flows in weakly accreting T Tauri stars. However, the higher accretion observed for most T Tauri stars ((M)overdot similar to 10(-8) M-circle dot yr(-1)) requires either larger stellar field strength and/or different magnetic topologies to allow for magnetospheric accretion.
Separation of scattering and selfaction revisited

The definition of scattering operator in Quantum Field Theory is critically reconsidered. The correct treatment of oneparticle states is connected with separation of selfaction from interaction. The formalism of functional integral is used for the description of such a separation via introduction of the quantum equation of motion. When I got invitation to contribute to the volume, dedicated to anniversary of Lev Lipatov I immediately agreed. One reason is evident — I highly respect Lev for his dedication to Quantum Field Theory, deep intuition and fantastic technical skill. The second is the planned title of this volume — “Subtleties of QFT”. So I decided to popularize one aspect of QFT which is not widely known. It is connected with definition of scattering. When I was learning QFT in the end of 50-ties of previous century, the scattering operator was defined by famous formula S = lim t→∞ t→−∞ e0 ′′ e ′′′e0 ′ with introduction of the interaction representation together with adiabatic limit, and use of the Wick theorem. Derivation of Feynman diagrams by Dyson [1] via these means was most popular. The infinities appearing in calculation were dealt with by renormalization and divergence of mass and charge were treated on the same footing. With some experience in quantum theory of scattering I was somewhat unhappy. Indeed, I already knew, that for the limit such as above the continuous spectra of H0 and H were to coincide, like it happens in scattering on potential where H = − 1 2m ∆+ v(x) = H0 + V with v(x) vanishing at large distances. On the other hand everybody knows, that perturbation shifts discrete spectrum. 1
MODELING THE BROADBAND EMISSION OF GRB 090902B

GRB 090902B, detected by the Fermi Large Array Telescope (Fermi/LAT), shows extended high-energy emission (>100 MeV) up to 103 s after the burst, and decays with time in a power law as t−1.5. It has also been observed by several follow-up low-energy instruments, including an early optical detection around 5000 s after the burst. The optical emission at early time decays faster than t−1.6, and has been suspected to originate from the reverse shock. We here explore the models that can possibly explain the broadband afterglow emission of GRB 090902B. We find that the reverse-shock model for the early optical emission would overpredict the radio afterglow flux that is inconsistent with observations. A partially radiative blast wave model, which though able to produce a sufficiently steep decay slope, cannot explain the broadband data of GRB 090902B. The two-component jet model, which consists of a narrow and bright jet component in the core and a surrounding wider and less energetic jet component, is shown to be able to explain the broadband afterglow data, including the LAT high-energy data after ∼50 s and low-energy (radio, optical, and X-ray) afterglow data. The early-time high-energy emission detected by LAT before ∼50 s is likely due to an internal origin similar to that of the sub-MeV emission. The highest energy (33 GeV) photon of GRB 090902B detected at 80 s can marginally be accommodated within the forward-shock emission under the optimistic condition that electrons are accelerated by the Bohm diffusive shock.
Experimental signatures of phase interference and subfemtosecond time dynamics on the incident energy axis of resonant inelastic x-ray scattering

Core hole resonance is used in X-ray spectroscopy to incisively probe the local electronic states of many-body systems. Here, resonant inelastic X-ray scattering (RIXS) is studied as a function of incident photon energy on Mott insulators SrCuO2 and NiO to examine how resonance states decay into different excitation symmetries at the transition metal M-, L- and K-edges. Quantum interference patterns characteristic of the two major RIXS mechanisms are identified within the data, and used to distinguish the attosecond scale scattering dynamics by which fundamental excitations of a many-body system are created. A function is proposed to experimentally evaluate whether a particular excitation has constructive or destructive interference in the RIXS cross-section, and corroborates other evidence that an anomalous excitation is present at the leading edge of the Mott gap in quasi-one dimensional SrCuO2.
Derived Categories

This is the fourth (and last) prepublication version of a book on derived categories, that will be published by Cambridge University Press. The purpose of the book is to provide solid foundations for the theory of derived categories, and to present several applications of this theory in commutative and noncommutative algebra. The emphasis is on constructions and examples, rather than on axiomatics. Here are the topics covered in the book: - A review of standard facts on abelian categories. - Differential graded algebra (DG rings, DG modules, DG categories and DG functors). - Triangulated categories and triangulated functors between them. How they arise from the DG background. The homotopy category K(A,M) of DG A-modules in M. - Localization of categories. The derived category D(A,M), which is the localization of K(A,M) with respect to the quasi-isomorphisms. - Left and right derived functors of a triangulated functor. - K-injective, K-projective and K-flat DG modules. Their roles, and their existence in several important algebraic situations. - Dualizing and residue complexes over commutative noetherian rings, including Van den Bergh rigidity. - Perfect DG modules and tilting DG bimodules over NC (noncommutative) DG rings. - NC connected graded rings, including Artin-Schelter regular rings. Derived torsion for NC connected graded rings, its relation to the chi condition of Artin-Zhang, and the NC MGM Equivalence. Balanced dualizing complexes, their uniqueness, existence and trace functoriality. - NC rigid dualizing complexes, following Van den Bergh. The uniqueness and existence of these complexes, a few examples, and their relation to Calabi-Yau rings. Readers of this preview version are urged to write to the author with any comments regarding errors, suggestions or questions.
A Light-curve Analysis of Gamma-Ray Nova V959 Mon: Distance and White Dwarf Mass

V959 Mon is a nova detected in gamma-rays. It was discovered optically about 50 days after the gamma-ray detection owing to its proximity to the Sun. The nova’s speed class is unknown because of the lack of the earlier half of its optical light curve and a short supersoft X-ray phase due to eclipse by the disk rim. Using the universal decline law and time-stretching method, we analyzed the data on V959 Mon and obtained nova parameters. We estimated the distance modulus in the V band to be (m − M)V = 13.15 ± 0.3 for the reddening of E(B − V) = 0.38 ± 0.01 by directly comparing it with novae of a similar type—LV Vul, V1668 Cyg, IV Cep, and V1065 Cen. The distance to V959 Mon is 2.5 ± 0.5 kpc. If we assume that the early phase of the light curve of V959 Mon is the same as that of time-stretched light curves of LV Vul, our model fitting of the light curve suggests that the white dwarf (WD) mass is 0.9–1.15 M⊙, which is consistent with a neon nova identification. At the time of gamma-ray detection the photosphere of the nova envelope extends to 5–8 R⊙ (about two or three times the binary separation) and the wind mass-loss rate is yr−1. The period of hard X-ray emission is consistent with the time of appearance of the companion star from the nova envelope. The short supersoft X-ray turnoff time is consistent with the epoch when the WD photosphere shrank to behind the rising disk rim, which occurred 500 days before nuclear burning turned off.
A peculiar thermonuclear X-ray burst from the transiently accreting neutron star SAX J1810.8–2609

Abstract We report on a thermonuclear (type-I) X-ray burst that was detected from the neutron star low-mass X-ray binary SAX J1810.8–2609 in 2007 with Swift. This event was longer (≃20 min) and more energetic (a radiated energy of Eb≃6.5×1039 erg) than other X-ray bursts observed from this source. A possible explanation for the peculiar properties is that the X-ray burst occurred during the early stage of the outburst when the neutron star was relatively cold, which allows for the accumulation of a thicker layer of fuel. We also report on a new accretion outburst of SAX J1810.8–2609 that was observed with MAXI and Swift in 2012. The outburst had a duration of ≃17 days and reached a 2–10 keV peak luminosity of ≃ 3 × 1037 (D/5.7 kpc)2 erg s−1. This is a factor >10 more luminous than the two previous outbursts observed from the source, and classifies it as a bright rather than a faint X-ray transient.
High Precision RC Relaxation Oscillator for Wide Supply Voltage Swing from 2.5V to 5.5V

A low-temperature drift current-mode relaxation oscillator suitable for wide supply voltage swing is presented. The characteristic that the delay of the buffer is proportional to the supply voltage and inversely proportional to the bias current is exploited. The bias of the buffer is provided by the current source that changes with the supply voltage, so as to achieve the purpose that the delay of the buffer is weakly correlated with the supply voltage and suppress the change of the output frequency. A temperature-dependent resistance is used to balance the delay of the buffer with temperature. The experimental results show that the typical frequency of the oscillator is 2MHz. The frequency variation is 0.33%/V for the supply voltage of 2. 5~5.5V and 40.6ppm/°C for temperature of −40~125°C.
Nagaoka states in the SU(n) Hubbard model

We present an extension of Nagaoka's theorem in the SU($n$) generalization of the infinite-$U$ Hubbard model. It is shown that, when there is exactly one hole, the fully polarized states analogous to the ferromagnetic states in the SU(2) Hubbard model are ground states. For a restricted class of models satisfying the connectivity condition, these fully polarized states are the unique ground states up to the trivial degeneracy due to the SU($n$) symmetry. We also give examples of lattices in which the connectivity condition can be verified explicitly. The examples include the triangular, kagome, and hypercubic lattices in $d (\ge 2)$ dimensions, among which the cases of $d=2$ and 3 are experimentally realizable in ultracold atomic gases loaded into optical lattices.
Imprints of Zero-Age Velocity Dispersions and Dynamical Heating on the Age-Velocity dispersion Relation

Observations of stars in the the solar vicinity show a clear tendency for old stars to have larger velocity dispersions. This relation is called the age-velocity dispersion relation (AVR) and it is believed to provide insight into the heating history of the Milky Way galaxy. Here, in order to investigate the origin of the AVR, we performed smoothed particle hydrodynamic simulations of the self-gravitating multiphase gas disks in the static disk-halo potentials. Star formation from cold and dense gas is taken into account, and we analyze the evolution of these star particles. We find that exponents of simulated AVR and the ratio of the radial to vertical velocity dispersion are close to the observed values. We also find that the simulated AVR is not a simple consequence of dynamical heating. The evolution tracks of stars with different epochs evolve gradually in the age-velocity dispersion plane as a result of: (1) the decrease in velocity dispersion in star forming regions, and (2) the decrease in the number of cold/dense/gas as scattering sources. These results suggest that the AVR involves not only the heating history of a stellar disk, but also the historical evolution of the ISM in a galaxy.
SINGLE- AND TWO-COMPONENT GAMMA-RAY BURST SPECTRA IN THE FERMI GBM-LAT ENERGY RANGE

Most Fermi gamma-ray burst spectra appear as either a broken power law extending to GeV energies or as a broken power with a separate GeV power-law component. Here we show that such spectra can be understood in terms of magnetically dominated relativistic jets where a dissipative photosphere produces the prompt MeV emission, which is extended into the GeV range by inverse Compton scattering in the external shock, with possible contributions from a reverse shock as well. The bulk Lorentz factors required in these models are in the range of 300–600, and the MeV–GeV time delays arise naturally. In some cases an optical flash and a sub-dominant thermal component are also present.
No magnetars in ULXs

We consider the current observed ensemble of pulsing ultraluminous X-ray sources (PULXs). We show that all of their observed properties (luminosity, spin period, and spin-up rate) are consistent with emission from magnetic neutron stars with fields in the usual range 1011--1013G⁠, which is collimated (‘beamed’) by the outflow from an accretion disc supplied with mass at a super-Eddington rate, but ejecting the excess, in the way familiar for other (non-pulsing) ULXs. The observed properties are inconsistent with magnetar-strength fields in all cases. We point out that all proposed pictures of magnetar formation suggest that they are unlikely to be members of binary systems, in agreement with the observation that all confirmed magnetars are single. The presence of magnetars in ULXs is therefore improbable, in line with our conclusions above.
Students' Understanding of Stern Gerlach Experiment

The Stern Gerlach experiment has played a central role in the discovery of spin angular momentum and it has also played a pivotal role in elucidating foundational issues in quantum mechanics. Here, we discuss investigation of students' difficulties related to the Stern Gerlach experiment by giving written tests and interviewing advanced undergraduate and graduate students in quantum mechanics. We also discuss preliminary data that suggest that the Quantum Interactive Learning Tutorial (QuILT) related to the Stern Gerlach experiment is helpful in improving students' understanding of these concepts.
Unbiased (reference-free) phase field imaging for general optical fields including phase discontinuities

A new numerically and experimentally tested measurement method for the local electrical light field including its phase is presented. The method is based on Self Referencing Interferograms (SRI) such as shearing interferograms. The complex electric field is the solution vector of a linear equation with the pixel resolved interference term E_2* E_1 as a parameter. Linearization of the non linear equations is achieved by using preknowledge in the intensity as obtained by a conventional image detetctor. The resulting linear equations are not based on any approximation, iterative perturbation expansion etc. but are exact. The method is non iterative and stable against noise for arbitrarily chosen test fields. Allowed fields can exhibit highly fluctuating amplitudes/phases on the pixel scale, areas of vanishing amplitude and Pi phase jumps. The spatial resolution is of pixel size. No reference beam and no diaphragms are used. The new method can be implemented as a fast, one shot per frame video system. An outlook on the space resolved measurement of non classical two photon states (including vacuum squeezed coherent states) is given.
HORIZON RUN 3: TOPOLOGY AS A STANDARD RULER

We study the physically self-bound cold dark matter halo distribution, which we associate with the massive galaxies within Horizon Run 3, to estimate the accuracy of the determination of the cosmological distance scale measured by the topology analysis. We apply the routine “Contour 3D” to the 108 Mock Survey of π steradians out to redshift z = 0.6, which effectively corresponds to the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) survey, and compare the topology with that of a Gaussian random phase field. We find that given three separate smoothing lengths λ = 15, 21, and 34 h −1 Mpc, the least χ2 fit genus per unit volume (g) yields a 1.7% fractional uncertainty in smoothing length and angular diameter distance to z = 0.6. This is an improvement on former calibrations and presents an error estimate competitive with baryon acoustic oscillation scale techniques. We also present three-dimensional graphics of the Horizon Run 3 spherical mock survey to show a wealth of large-scale structures of the universe that are expected for surveys like BOSS.
Quantum quenches from integrability: the fermionic pairing model

Understanding the non-equilibrium dynamics of extended quantum systems after the trigger of a sudden, global perturbation (quench) represents a daunting challenge, especially in the presence of interactions. The main difficulties stem from both the vanishing timescale of the quench event, which can thus create arbitrarily high energy modes, and its non-local nature, which curtails the utility of local excitation bases. We here show that nonperturbative methods based on integrability can prove sufficiently powerful to completely characterize quantum quenches: we illustrate this using a model of fermions with pairing interactions (Richardson’s model). The effects of simple (and multiple) quenches on the dynamics of various important observables are discussed. Many of the features that we find are expected to be universal to all kinds of quench situations in atomic physics and condensed matter.
Control chart using bootstrap method for logistic-exponential percentiles

Lan and Leemis (2008) introduced logistic-exponential (LE) distribution which has varied applications in lifetime modellings. In this article, we consider parametric bootstrap control charts (BCCs) for detecting a shift in the percentile of LE distribution in a process monitoring situation. Four parametric BCCs based on maximum likelihood method, method of least squares, method of Cramer-von-Mises and ` method of maximum product of spacings are used for monitoring percentiles of LE distribution. We perform simulations to see the performances of the proposed four BCCs with respect to average run length. Finally, one data set is analyzed to illustrate our results.
Simulation of quantum magnetism in mixed-spin systems with impurity-doped ion crystals

We propose the realization of linear crystals of cold ions that contain different atomic species for investigating quantum phase transitions and frustration effects in spin systems beyond the commonly considered case of . Mutual spin–spin interactions between ions can be tailored via the Zeeman effect by applying oscillating magnetic fields with strong gradients. Further, collective vibrational modes in the mixed ion crystal can be used to enhance and to vary the strength of spin–spin interactions and even to switch the nature of the interacting forces from a ferro- to an antiferromagnetic character. We consider the behavior of the effective spin–spin couplings in an ion crystal of spin-1/2 ions doped with high-magnetic-moment ions with spin S = 3. We analyze the ground state phase diagram and find regions with different spin orders including ferrimagnetic states. In the most simple nontrivial example, we deal with a linear {Ca+,Mn+,Ca+} crystal with spins of . To demonstrate feasibility with current state-of-the-art experiments, we discuss how quantum phases might be detected using a collective Stern–Gerlach effect of the ion crystal and high-resolution spectroscopy. Here, the state-dependent laser-induced fluorescence of the indicator spin-1/2 ion, of species 40Ca+, is used to reveal also the spin state of the simulator spin-3 ions, 50Mn+, which does not possess suitable levels for optical excitation and detection.