Miracle-dz/UniFAR-FTUs huggingface dataset:
Theory of hole propagation in one-dimensional insulators and superconductors

The dynamical properties of hole motion in an antiferromagnetic background are determined in one-dimensional models in zero magnetic field, where spin isotropy holds, as well as in an external magnetic field. The latter case is also relevant, via particle-hole transformation, to the problem of hole propagation in one-dimensional ``superconductors. '' The singularities in the spectral function are investigated by means of bosonization techniques and perturbation theories. Results are then compared with Bethe ansatz solutions and Lanczos diagonalizations. The formalism also leads to interesting connections to the single impurity problem in Luttinger liquids. A rich structure is found in the spectral function whenever spin isotropy is broken, suggesting the presence of exotic momentum dependence in photoemission spectra of (quasi) one dimensional materials.
Constraints on backreaction in dust universes

We study backreaction in dust universes using exact equations which do not rely on perturbation theory, concentrating on theoretical and observational constraints. In particular, we discuss the recent suggestion (Kolb et al 2005 Preprint hep-th/0503117) that superhorizon perturbations could explain present-day accelerated expansion as a useful example which can be ruled out. We note that a backreaction explanation of late-time acceleration will have to involve spatial curvature and subhorizon perturbations.
The Type-II Singular See-Saw Mechanism

The singular see-saw mechanism is a variation of the see-saw mechanism whereby the right-chiral neutrino Majorana mass matrix is singular. Previous works employing the singular see-saw mechanism have assumed a vanishing left-chiral Majorana mass matrix. We study the neutrino spectrum obtained under a singular see-saw mechanism when the left-chiral neutrinos possess a nonzero Majorana mass matrix. We refer to this as the type-II singular see-saw mechanism. The resulting neutrino spectrum is found to be sensitive to the hierarchy of the Dirac and Majorana mass scales used and we explore the phenomenological consequences of the candidate hierarchies. The compatibility of the resulting spectra with the body of neutrino oscillation data is discussed. It is found that neutrino mass matrices with this structure result in 3+1 or 2+2 neutrino spectra, making it unlikely that this mass matrix structure is realized in nature. If the left-chiral Majorana mass matrix is also singular we show that a type-II singular see-saw mechanism can realize a spectrum of one active-sterile pseudo-Dirac neutrino in conjunction with two active Majorana neutrinos effectively decoupled from the sterile sector. This realizes a scheme discussed in the literature in relation to astrophysical neutrino fluxes.
X-ray analysis of the accreting supermassive black hole in the radio galaxy PKS 2251+11

Context. We have investigated the dichotomy between jetted and non-jetted active galactic nuclei (AGNs), focusing on the fundamental differences of these two classes in the accretion physics onto the central supermassive black hole (SMBH). We tested the validity of the unification model of AGNs through the characterization of the mutual interaction between accreting and outflowing matter in radio galaxies. Aims. Our aim is to study and constrain the structure, kinematics and physical state of the nuclear environment in the broad line radio galaxy (BLRG) PKS 2251+11. The high X-ray luminosity and the relative proximity make such AGN an ideal candidate for a detailed analysis of the accretion regions in radio galaxies. The investigation will help to shed light on the analogies and differences between the BLRGs and the larger class of radio-quiet Seyfert galaxies and hence on the processes that trigger the launch of a relativistic jet. Methods. We performed a spectral and timing analysis of a ∼64 ks observation of PKS 2251+11 in the X-ray band with XMM-Newton. We modeled the spectrum considering an absorbed power law superimposed to a reflection component. We performed a time-resolved spectral analysis to search for variability of the X-ray flux and of the individual spectral components. Results. We find that the power law has a photon index Γ = 1.8 ± 0.1, absorbed by an ionized partial covering medium with a column density NH = (10.1 ± 0.8) × 1023 cm−2, a ionization parameter log ξ = 1.3 ± 0.1 erg s−1 cm and a covering factor f ≃ 90%. Considering a density of the absorber typical of the broad line region (BLR), its distance from the central SMBH is of the order of r ∼ 0.1 pc. An Fe Kα emission line is found at 6.4 keV, whose intensity shows variability on timescales of hours. We derive that the reflecting material is located at a distance r ≳ 600rs, where rs is the Schwarzschild radius. Conclusions. Concerning the X-ray properties, we found that PKS 2251+11 does not differ significantly from the non-jetted AGNs, confirming the validity of the unified model in describing the inner regions around the central SMBH, but the lack of information regarding the state of the very innermost disk and SMBH spin still leaves unconstrained the origin of the jet.
Generalized Constructive Tree Weights

The Loop Vertex Expansion (LVE) is a quantum field theory (QFT) method which explicitly computes the Borel sum of Feynman perturbation series. This LVE relies in a crucial way on symmetric tree weights which define a measure on the set of spanning trees of any connected graph. In this paper we generalize this method by defining new tree weights. They depend on the choice of a partition of a set of vertices of the graph, and when the partition is non-trivial, they are no longer symmetric under permutation of vertices. Nevertheless we prove they have the required positivity property to lead to a convergent LVE; in fact we formulate this positivity property precisely for the first time. Our generalized tree weights are inspired by the Brydges-Battle-Federbush work on cluster expansions and could be particularly suited to the computation of connected functions in QFT. Several concrete examples are explicitly given.
Modified log-Sobolev inequalities for strong-Rayleigh measures

We establish universal modified log-Sobolev inequalities for reversible Markov chains on the boolean lattice $\{0,1\}^n$, under the only assumption that the invariant law $\pi$ satisfies a form of negative dependence known as the \emph{stochastic covering property}. This condition is strictly weaker than the strong Rayleigh property, and is satisfied in particular by all determinantal measures, as well as any product measure over the set of bases of a balanced matroid. In the special case where $\pi$ is $k-$homogeneous, our results imply the celebrated concentration inequality for Lipschitz functions due to Pemantle \& Peres (2014). As another application, we deduce that the natural Monte-Carlo Markov Chain used to sample from $\pi$ has mixing time at most $kn\log\log\frac{1}{\pi(x)}$ when initialized in state $x$. This considerably improves upon the $kn\log\frac{1}{\pi(x)}$ estimate recently obtained under stronger assumptions by Anari, Oveis Gharan \& Rezaei (2016).
The Inner Nebula and Central Binary of the Symbiotic Star HM Sagittae

We present contemporaneous Hubble Space Telescope Wide Field Planetary Camera 2 and Very Large Array observations of the symbiotic nova HM Sge. We identify a number of discreet features at spatial scales smaller than ~0. ″1 embedded in the extended nebula, with radio and optical emission well correlated in the inner 1''. For the first time we measure the positions of the binary components of a symbiotic star directly. We estimate the projected angular binary separation to be 40 ± 9 mas, with the binary axis at a position angle of 130° ± 10°. The latter is consistent with previous estimates made by indirect methods. The binary separation is consistent with a previous estimate of 50 AU if the distance is 1250 ± 280 pc. Temperature and density diagnostics show two distinct regions in the surrounding nebula, with a cool wedge to the southwest. An extinction map indicates the true interstellar extinction to be no more than E(B-V) = 0.35. This is consistent with a minimum distance of ~700 pc, but this would be reduced if there is a circumstellar contribution to the minimum in the extinction map. The extinction map also suggests a patchy dust distribution. We suggest that a southern concentration of dust and the southwest wedge are associated with the cool component wind. Alternatively, the southern dust concentration is the cause of the cool wedge, since it shields part of the nebula from the hot-component radiation field.
Finite Representability of Integers as 2-Sums

A set $\mathcal{A}$ is said to be an additive $h$-basis if each element in $\{0,1,\ldots,hn\}$ can be written as an $h$-sum of elements of $\mathcal{A}$ in {\it at least} one way. We seek multiple representations as $h$-sums, and, in this paper we make a start by restricting ourselves to $h=2$. We say that $\mathcal{A}$ is said to be a truncated $(\alpha,2,g)$ additive basis if each $j\in[\alpha n, (2-\alpha)n]$ can be represented as a $2$-sum of elements of $\mathcal{A}$ in at least $g$ ways. In this paper, we provide sharp asymptotics for the event that a randomly selected set is a truncated $(\alpha,2,g)$ additive basis with high or low probability.
The Milky Way like galaxy NGC 6384 and its nuclear star cluster at high NIR spatial resolution using LBT/ARGOS commissioning data

We analyse high spatial resolution near infrared (NIR) imaging of NGC 6384, a Milky Way like galaxy, using ARGOS commissioning data at the Large Binocular Telescope (LBT). ARGOS provides a stable PSFFWHM = 0. '' 2-0. '' 3 correction of the ground layer across the LUCI 2 NIR camera 4 x 4 arcmin field by using six laser guide stars (three per telescope) and a natural guide star for tip-tilt sensing and guiding. Enabled by this high spatial resolution, we analyse the structure of the nuclear star cluster (NSC) and the central kiloparsec of NGC 6384. We find via 2D modelling that the NSC (r(eff )similar or equal to 10 pc) is surrounded by a small (r(eff) similar or equal to 100 pc) and a larger Sersic (r(eff )similar or equal to 400 pc), all embedded within the NGC 6384 large-scale boxy/X-shaped bulge and disc. This proof-of-concept study shows that with the high spatial resolution achieved by ground-layer AO we can push such analysis to distances previously only accessible from space. SED-fitting to the NIR and optical HST photometry allowed to leverage the age-metallicity- extinction degeneracies and derive the effective NSC properties of an young to old population mass ratio of 8 per cent with M-*old similar or equal to 3.5 x 10(7) M-circle dot, Age(old),(young) = 10.9 +/- 1.3 Gyr and 226 Myr +/- 62 per cent, metallicity [M/H] = -0.11 +/- 0.16, and 0.33 +/- 39 per cent dex, and E(B - V). 0.63 and 1.44 mag.
Theory of nonreciprocal spin-wave excitations in spin Hall oscillators with Dzyaloshinskii-Moriya interaction

A two-dimensional analytical model for the description of the excitation of nonreciprocal spin waves by spin current in spin-Hall oscillators in the presence of the interfacial Dzyaloshinskii-Moriya interaction (i-DMI) is developed. The theory allows one to calculate the threshold current for the excitation of spin waves, as well as the frequencies and spatial profiles of the excited spin wave modes. It is found, that the frequency of the excited spin waves exhibits a quadratic red shift with the i-DMI strength. At the same time, in the range of small and moderate values of the i-DMI constant, the averaged wave number of the excited spin waves is almost independent of the i-DMI, which results in a rather weak dependence on the i-DMI of the threshold current of the spin wave excitation. The obtained analytical results are confirmed by the results of micromagnetic simulations.
Symmetric inner-iteration preconditioning for rank-deficient least squares problems

Stationary iterative methods with a symmetric splitting matrix are performed as inner-iteration preconditioning for Krylov subspace methods. We give a necessary and sufficient condition such that the inner-iteration preconditioning matrix is definite, and show that conjugate gradient (CG) method preconditioned by the inner iterations determines a solution of a symmetric and positive semidefinite linear system, and the minimal residual (MR) method preconditioned by the inner iterations determines a solution of a symmetric linear system including the singular case. These results are applied to the CG and MR-type methods such as the CGLS, LSMR, and CGNE methods preconditioned by inner iterations, and thus justify using these methods for solving least squares and minimum-norm solution problems those coefficient matrices are not necessarily of full rank. Thus, we complement the theory of these methods presented in [K. Morikuni and K. Hayami, SIAM J. Matrix Appl. Anal. , 34 (2013), pp. 1-22], [K. Morikuni and K. Hayami, SIAM J. Matrix Appl. Anal. , 36 (2015), pp. 225-250], and give bounds for these methods.
Evidence of hot and cold spots on the Fermi surface of LiFeAs

Angle-resolved photoemission spectroscopy (ARPES) is used to study the energy and momentum dependence of the inelastic scattering rates and the mass renormalization of charge carriers in LiFeAs at several high symmetry points in the Brillouin zone. A strong and linear-in-energy scattering rate is observed for sections of the Fermi surface having predominantly Fe $3d_{xy/yz}$ orbital character on the inner hole and on electron pockets. We assign them to hot spots with marginal Fermi liquid character inducing high antiferromagnetic and pairing susceptibilities. The outer hole pocket, with Fe $3d_{xy}$ orbital character, has a reduced but still linear in energy scattering rate. Finally, we assign sections on the middle hole pockets with Fe $3d_{xz,yz}$ orbital character and on the electron pockets with Fe $3d_{xy}$ orbital character to cold spots because there we observe a quadratic-in-energy scattering rate with Fermi-liquid behavior. These cold spots prevail the transport properties. Our results indicate a strong $\it{momentum}$ dependence of the scattering rates. We also have indications that the scattering rates in correlated systems are fundamentally different from those in non-correlated materials because in the former the Pauli principle is not operative. We compare our results for the scattering rates with combined density functional plus dynamical mean-field theory calculations. The work provides a generic microscopic understanding of macroscopic properties of multiorbital unconventional superconductors.
Static friction boost in edge-driven incommensurate contacts

We present a numerical investigation of the size scaling of static friction in incommensurate two dimensional contacts performed for different lateral loading configurations. Results of model simulations show that both the absolute value of the force $F_s$ and the scaling exponent $\gamma$ strongly depend on the loading configuration adopted to drive the slider along the substrate. Under edge-loading a sharp increase of static friction is observed above a critical size corresponding to the appearance of a localized commensurate dislocation. Noticeably, the existence of sublinear scaling, which is a fingerprint of superlubricity, does not conflict with the possibility to observe shear-induced localized commensurate regions at the contact interface. Atomistic simulations of gold islands sliding over graphite corroborate these findings suggesting that similar elasticity effects should be at play in real frictional contacts.
Evolution of binaries with compact objects in globular clusters

Abstract Dynamical interactions that take place between objects in dense stellar systems lead to frequent formation of exotic stellar objects, unusual binaries, and systems of higher multiplicity. They are most important for the formation of binaries with neutron stars and black holes, which are usually observationally revealed in mass-transferring binaries. Here we review the current understanding of compact object's retention, of the metallicity dependence on the formation of low-mass X-ray binaries with neutron stars, and how mass-transferring binaries with a black hole and a white dwarf can be formed. We discuss as well one old unsolved puzzle and two new puzzles posed by recent observations: what descendants do ultra-compact X-ray binaries produce, how are very compact triples formed, and how can black hole low-mass X-ray binaries acquire non-degenerate companions?
A spectral sequence for the Hochschild cohomology of a coconnective dga

A spectral sequence for the computation of the Hochschild cohomology of a coconnective dga over a field is presented. This spectral sequence has a similar flavour to the spectral sequence constructed by Cohen, Jones and Yan for the computation of the loop homology of a closed orientable manifold. Using this spectral sequence we identify a class of spaces for which the Hochschild cohomology of their mod-p cochain algebra is Noetherian. This implies, among other things, that for such a space the derived category of mod-p chains on its loop-space carries a theory of support varieties.
Polynomial functors and combinatorial Dyson–Schwinger equations

We present a general abstract framework for combinatorial Dyson–Schwinger equations, in which combinatorial identities are lifted to explicit bijections of sets, and more generally equivalences of groupoids. Key features of combinatorial Dyson–Schwinger equations are revealed to follow from general categorical constructions and universal properties. Rather than beginning with an equation inside a given Hopf algebra and referring to given Hochschild 1-cocycles, our starting point is an abstract fixpoint equation in groupoids, shown canonically to generate all the algebraic structures. Precisely, for any finitary polynomial endofunctor P defined over groupoids, the system of combinatorial Dyson–Schwinger equations X = 1 + P(X) has a universal solution, namely the groupoid of P-trees. The isoclasses of P-trees generate naturally a Connes–Kreimer-like bialgebra, in which the abstract Dyson–Schwinger equation can be internalised in terms of canonical B+-operators. The solution to this equation is a series (the.
New Period-Luminosity and Period-Color relations of classical Cepheids: I. Cepheids in the Galaxy

Galactic fundamental-mode Cepheids with good B, V, and (in most cases) I photometry by Berdnikov et al. (2000) and with homogenized color excesses E(B V) based on Fernie et al. (1995) are used to determine their period-color (P-C) relation in the range 0:4 1:4). The latter eect is enhanced by a suggestive break of the P-L relation of LMC and SMC at log P= 1: 0t owards still shallower values as shown in a forthcoming paper.
Multiplicative chaos measures for a random model of the Riemann zeta function

We prove convergence of a stochastic approximation of powers of the Riemann $\zeta$ function to a non-Gaussian multiplicative chaos measure, and prove that this measure is a non-trivial multifractal random measure. The results cover both the subcritical and critical chaos. A basic ingredient of the proof is a 'good' Gaussian approximation of the induced random fields that is potentially of independent interest.
The Hα Luminosity Function and Global Star Formation Rate from Redshifts of 1-2

We present a luminosity function for Hα emission from galaxies at redshifts between 0.7 and 1.9 based on slitless spectroscopy with the near-infrared camera and multiobject spectrometer on the Hubble Space Telescope. The luminosity function is well fit by a Schechter function over the range 6 × 1041 < L41 < 2 × 1043 ergs s-1 with L* = 7 × 1042 ergs s-1 and ϕ* = 1.7 × 10-3 Mpc-3 for H0 = 50 km s-1 Mpc-1 and q0 = 0.5. We derive a volume-averaged star formation rate at z = 1.3 ± 0.5 of 0.13 M☉ yr-1 Mpc-3 without correction for extinction. The star formation rate that we derive at ~6500 Å is a factor of 3 higher than that deduced from 2800 Å continua. If this difference is caused entirely by reddening, the extinction correction at 2800 Å is quite significant. The precise magnitude of the total extinction correction at rest-frame UV wavelengths (e.g., 2800 and 1500 Å) is sensitive to the relative spatial distribution of the stars, gas, and dust, as well as to the extinction law. In the extreme case of a homogeneous foreground dust screen and a Milky Way or LMC extinction law, we derive a total extinction at 2800 Å of 2.1 mag, or a factor of 7 correction to the UV luminosity density. If we use the Calzetti reddening curve, which was derived for the model in which stars, gas, and dust are well mixed and nebular gas suffers more extinction than stars, our estimate of A2800 is increased by more than 1 mag.
On Some Adaptive Mirror Descent Algorithms for Convex and Strongly Convex Optimization Problems with Functional Constraints

In this paper some adaptive mirror descent algorithms for problems of minimization convex objective functional with several convex Lipschitz (generally, non-smooth) functional constraints are considered. It is shown that the methods are applicable to the objective functionals of various level of smoothness: the Lipschitz condition is valid either for the objective functional itself or for its gradient or Hessian (and the functional may not satisfy the Lipschitz condition). By using the restart technique methods for strongly convex minimization problems are proposed. Estimates of the rate of convergence of the considered algorithms are obtained depending on the level of smoothness of the objective functional. Numerical experiments illustrating the advantages of the proposed methods for some examples are presented.
Preclinical and clinical imaging techniques as pathophysiological biomarkers — A preface to the special issue “Brain Imaging”

Molecular imaging techniques have become important tools to characterize and measure biological processes at the cellular and molecular levels. Nowadays, molecular imaging techniques are widely used in preclinical and clinical studies to assess the molecular dynamics under physiological conditions and during pathological processes. This special issue on Brain Imaging (https://onlinelibrary.wiley.com/doi/toc/10.1111/[ISSN]1471‐4159.brain‐imaging) will highlight some of the recent advances in developing new tools and applying molecular imaging techniques to understand biomarker dynamics in health and diseases.
Sevoflurane reverses cisplatin resistance in neuroblastoma cells through the linc00473/miR-490-5p/AKT1 axis

Objectives: To determine whether sevoflurane regulates cisplatin resistance in neuroblastoma cells. Methods: The SH-SY5Y cell line with cisplatin-resistant phenotype (SH-SY5Y-SR) was generated. Cells were co-treated with sevoflurane and cisplatin to seek the sevoflurane function on cisplatin resistance. Key targets of sevoflurane treatment were determined using sequencing (ribonucleic acid [RNA-seq]). Cells were then transfected with specific vectors. Linc00473 and microRNA-490-5p (miR-490-5p) levels were detected using reverse transcriptase quantitative real-time reverse transcription PCR (RT-qPCR). Linc00473-miR-490-5p binding was confirmed using a luciferase reporter-gene assay. After treatment, cell proliferation, viability, and caspase-3 activity were measured to determine the effects of treatment on tumor cells. Each experimental result is based on three independent experiments. Results: Co-treatment with sevoflurane and cisplatin markedly improved the sensitivity of SH-SY5Y-SR cells to cisplatin, which inhibited the occurrence of cisplatin resistance. The RNA-sequencing analysis and RT-qPCR showed that sevoflurane inhibited linc00473 expression. Overexpression of linc00473 promoted cell proliferation, inhibited apoptosis, and promoted cisplatin resistance. The linc00473/miR-490-5p/V-akt murine thymoma viral oncogene homolog 1 (AKT1) axis was found to mediate the regulatory effects of sevoflurane on cisplatin resistance. Conclusion: Sevoflurane has great clinical potential against cisplatin-resistant tumors. Further animal experiments and clinical trials are required to achieve this goal.