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We present a comprehensive multiwavelength investigation of a likely massive young cluster `IRAS 05100+3723' and its environment with the aim to understand its formation history and feedback effects. We find that IRAS 05100+3723 is a distant ($\sim$3.2 kpc), moderate mass ($\sim$500 \msun), young ($\sim$3 Myr) cluster with its most massive star being an O8.5V-type. From spectral modeling, we estimate the effective temperature and log $g$ of the star as $\sim$33,000 K and $\sim$3.8, respectively. Our radio continuum observations reveal that the star has ionized its environment forming an HII region of size $\sim$2.7 pc, temperature $\sim$5,700 K, and electron density $\sim$165 cm$^{-3}$. However, our large-scale dust maps reveal that it has heated the dust up to several parsecs ($\sim$10 pc) in the range 17$-$28 K and the morphology of warm dust emission resembles a bipolar HII region. From dust and $^{13}$CO gas analyses, we find evidences that the formation of the HII region has occurred at the very end of a long filamentary cloud around 3 Myr ago, likely due to edge collapse of the filament. We show that the HII region is currently compressing a clump of mass $\sim$2700 \msun at its western outskirts, at the junction of the HII region and filament. We observe several 70 $\mu$m point sources of intermediate-mass and class 0 nature within the clump. We attribute these sources as the second generation stars of the complex. We propose that the star formation in the clump is either induced or being facilitated by the compression of the expanding HII region onto the inflowing filamentary material., Comment: ApJ, accepted

Cities are characterized by the presence of a dense population with a high potential for interactions between individuals of diverse backgrounds. They appear in parallel to the Neolithic revolution a few millennia ago. The advantages brought in terms of agglomeration for economy, innovation, social and cultural advancements have kept them as a major landmark in recent human history. There are many different aspects to study in urban systems from a scientific point of view, just to name a few one can concentrate in demography and population evolution, mobility, economic output, land use and urban planning, home accessibility and real estate market, energy and water consumption, waste processing, health, education, integration of minorities, etc. In the last decade, the introduction of communication and information technologies have enormously facilitated the collection of datasets on these and other questions, making possible a more quantitative approach to city science. All these topics have been addressed in many works in the literature, and we do not intend to offer here a systematic review. Instead, we will only provide a brief taste of some of these above-mentioned aspects, which could serve as an introduction to a subsequent special number. Such a non-systematic view will lead us to leave outside many relevant papers, and for this we apologise., Comment: 10 pages text, 10 pages references

The visual functions of visual prostheses such as field of view, resolution and dynamic range, seriously restrict the person's ability to navigate in unknown environments. Implanted patients still require constant assistance for navigating from one location to another. Hence, there is a need for a system that is able to assist them safely during their journey. In this work, we propose an augmented reality navigation system for visual prosthesis that incorporates a software of reactive navigation and path planning which guides the subject through convenient, obstacle-free route. It consists on four steps: locating the subject on a map, planning the subject trajectory, showing it to the subject and re-planning without obstacles. We have also designed a simulated prosthetic vision environment which allows us to systematically study navigation performance. Twelve subjects participated in the experiment. Subjects were guided by the augmented reality navigation system and their instruction was to navigate through different environments until they reached two goals, cross the door and find an object (bin), as fast and accurately as possible. Results show how our augmented navigation system help navigation performance by reducing the time and distance to reach the goals, even significantly reducing the number of obstacles collisions, compared to other baseline methods.

Linear polarimetric transformations of light polarization states by the action of material media are fully characterized by the corresponding Mueller matrices, which contain in an implicit and intricate manner all measurable information on such transformations. The general characterization of Mueller matrices relies on the nonnegativity of the associated coherency matrix, which can be mathematically formulated through the nonnegativity of its eigenvalues. The enormously involved explicit algebraic form of such formulation prevents its interpretation in terms of simple physical conditions. In this work, a general and simple characterization of Mueller matrices is presented based on their statistical structure. The concepts associated with the retardance, enpolarization and depolarization properties as well as the essential coupling between the two latter are directly described in the light of the new approach., Comment: 8 pages

In this work, we compute the entanglement entropy in continuous icMERA tensor networks for large $N$ models at strong coupling. Our results show that the $1/N$ quantum corrections to the Fisher information metric (interpreted as a local bond dimension of the tensor network) in an icMERA circuit, are related to quantum corrections to the minimal area surface in the Ryu-Takayanagi formula. Upon picking two different non-Gaussian entanglers to build the icMERA circuit, the results for the entanglement entropy only differ at subleading orders in $1/G_N$, i.e, at the structure of the quantum corrections in the bulk. The fact that the large $N$ part of the entropy can be always related to the leading area term of the holographic calculation is very suggestive. These results, constitute the first tensor network calculations at large $N$ and strong coupling simultaneously, pushing the field of tensor network descriptions of the emergence of dual spacetime geometries from the structure of entanglement in quantum field theory., Comment: 48 pages, 4 figures. v3: Withdraw from SciPost due to lack of review. It matches the published version in JHEP

We present results of an optical spectroscopic survey using SALT and NOT to build a WISE mid-infrared color-based, dust-unbiased sample of powerful radio-bright ($>$200 mJy at 1.4 GHz) AGN for the MeerKAT Absorption Line Survey (MALS). Our sample has 250 AGN (median $z=1.8$) showing emission lines, 26 with no emission lines, and 27 without optical counterparts. Overall, our sample is fainter ($\Delta i$=0.6 mag) and redder ($\Delta(g-i)$=0.2 mag) than radio-selected quasars, and representative of fainter quasar population detected in optical surveys. About 20% of the sources are narrow line AGN (NLAGN) $-$ 65% of these, at $z < 0.5$ are galaxies without strong nuclear emission, and 10% at $z>1.9$, have emission line ratios similar to radio galaxies. The farthest NLAGN in our sample is M1513$-$2524 ($z_{em}=3.132$), and the largest (size$\sim$330 kpc) is M0909$-$3133 ($z_{em}=0.884$). We discuss in detail 110 AGN at $1.9 < z < 3.5$. Despite representing the radio loudest quasars (median $R$=3685), their Eddington ratios are similar to the SDSS quasars having lower $R$. We detect 4 CIV BALQSOs, all among AGN with least $R$, and highest black hole masses and Eddington ratios. The BAL detection rate ($4^{+3}_{-2}$%) is consistent with that seen in extremely powerful ($L_{1.4GHz}>10^{25}$ WHz$^{-1}$) quasars. Using optical light-curves, radio polarization and $\gamma$-ray detections, we identify 7 high-probability BL Lacs. We also summarize the full MALS footprint to search for HI 21-cm and OH 18-cm lines at $z<2$., Comment: 62 pages, 15 figures and 3 tables; accepted in ApJ (updated the redshift of M1312-2026 to z=0.977)

We investigate the spectrum of linearized excitations of global vortices in $2+1$ dimensions. After identifying the existence of localized excitation modes, we compute the decay time scale of the first two and compare the results to the numerical evolution of the full non-linear equations. We show numerically how the interaction of vortices with an external source of radiation or other vortices can excite these modes dynamically. We then simulate the formation of vortices in a phase transition and their interaction with a thermal bath estimating the amplitudes of these modes in each case. These numerical experiments indicate that even though, in principle, vortices are capable of storing a large amount of energy in these internal excitations, this does not seem to happen dynamically. We then explore the evolution of a network of vortices in an expanding (2+1) dimensional background, in particular in a radiation dominated universe. We find that vortices are still excited after the course of the cosmological evolution but again the level of excitation is very small. The extra energy in the vortices in these cosmological simulations never exceeds the $1\%$ level of the total mass of the core of the vortex., Comment: 46 pages, 15 figures; clarifications and references regarding the total number of bound states added

Numerous early warning systems based on rainfall measurements have been designed over the last decades to forecast the onset of rainfall-induced shallow landslides. However, their use over large areas poses challenges due to uncertainties related with the interaction among various controlling factors. We propose a hybrid stochastic-mechanical approach to quantify the role of the hydro-mechanical factors influencing slope stability and rank their importance. The proposed methodology relies on a physically-based model of landslide triggering, and a stochastic approach treating selected model parameters as correlated aleatory variables. The features of the methodology are illustrated by referencing data for Campania, an Italian region characterized by landslide-prone volcanic deposits. Synthetic intensity-duration (ID) thresholds are computed through Monte Carlo simulations. Several key variables are treated as aleatoric, constraining their statistical properties through available measurements. The variabilities of topographic features (e.g., slope angle), physical and hydrological properties (e.g., porosity, dry unit weight ${\gamma}_d$, and saturated hydraulic conductivity, $K_s$), and pre-rainstorm suction is evaluated to inspect its role on the resulting scatter of ID thresholds. We find that: i) $K_s$ is most significant for high-intensity storms; ii) in steep slopes, changes in pressure head greatly reduce the timescale of landslide triggering, making the system heavily reliant on initial conditions; iii) for events occurring at long failure times (gentle slopes and/or low intensity storms), the significance of the evolving stress level (through ${\gamma}_d$) is highest. The proposed approach can be translated to other regions, expanded to encompass new aleatory variables, and combined with other hydro-mechanical triggering models., Comment: 22 pages, 10 figures

Spin-lattice relaxation is a key open problem to understand the spin dynamics of single-molecule magnets and molecular spin qubits. While modelling the coupling between spin states and local vibrations allows to determine the more relevant molecular vibrations for spin relaxation, this is not sufficient to explain how energy is dissipated towards the thermal bath. Herein, we employ a simple and efficient model to examine the coupling of local vibrational modes with long-wavelength longitudinal and transverse phonons in the clock-like spin qubit [Ho(W$_5$O$_{18}$)$_2$]$^{9-}$. We find that in crystals of this polyoxometalate the vibrational mode previously found to be vibronically active at low temperature does not couple significantly to lattice phonons. This means that further intramolecular energy transfer via anharmonic vibrations is necessary for spin relaxation in this system. Finally, we discuss implications for the spin-phonon coupling of [Ho(W$_5$O$_{18}$)$_2$]$^{9-}$ deposited on a MgO (001) substrate, offering a simple methodology that can be extrapolated to estimate the effects on spin relaxation of different surfaces, including 2D materials.

Context. Direct observation of gamma-ray emission from the decay of $^{18}$F ejected in classical nova outbursts remains a major focus of the nuclear astrophysics community. However, modeling the abundance of ejected $^{18}$F, and thus the predicted detectability distance of a gamma-ray signal near 511 keV emitted from these transient thermonuclear episodes, is hampered by significant uncertainties in our knowledge of the key $^{18}$F(p,$\alpha$) reaction rate. Aims. We analyze uncertainties in the most recent nuclear physics experimental results employed to calculate the $^{18}$F(p,$\alpha$) reaction rate. Our goal is to determine which uncertainties have the most profound influence on the predicted abundance of $^{18}$F ejected from novae, in order to guide future experimental works. Methods. We calculated a wide range of $^{18}$F(p,$\alpha$) reaction rates using R-Matrix formalism, allowing us to take into account all interference effects. Using a selection of 16 evenly-spaced rates over the full range, we performed 16 new hydrodynamic nova simulations. Results. We performed one of the most thorough theoretical studies of the impact of the $^{18}$F(p,$\alpha$) reaction in classical novae to date. The $^{18}$F(p,$\alpha$) rate remains highly uncertain at nova temperatures, resulting in a factor ~10 uncertainty in the predicted abundance of $^{18}$F ejected from nova explosions. We also found that the abundance of $^{18}$F may be strongly correlated with that of $^{19}$F. Conclusions. Despite numerous nuclear physics uncertainties affecting the $^{18}$F(p,$\alpha$) reaction rate, which are dominated by unknown interference signs between 1/2$^+$ and 3/2$^+$ resonances, future experimental work should focus on firmly and precisely determining the directly measurable quantum properties of the subthreshold states in the compound nucleus $^{19}$Ne near 6.13 and 6.29 MeV., Comment: Accepted for publication in Astronomy & Astrophysics 4 June 2021 as manuscript no. AA/2021/40339

Cultural diversity encoded within languages of the world is at risk, as many languages have become endangered in the last decades in a context of growing globalization. To preserve this diversity, it is first necessary to understand what drives language extinction, and which mechanisms might enable coexistence. Here, we study language shift mechanisms using theoretical and data-driven perspectives. A large-scale empirical analysis of multilingual societies using Twitter and census data yields a wide diversity of spatial patterns of language coexistence. It ranges from a mixing of language speakers to segregation with multilinguals on the boundaries of disjoint linguistic domains. To understand how these different states can emerge and, especially, become stable, we propose a model in which language coexistence is reached when learning the other language is facilitated and when bilinguals favor the use of the endangered language. Simulations carried out in a metapopulation framework highlight the importance of spatial interactions arising from people mobility to explain the stability of a mixed state or the presence of a boundary between two linguistic regions. Further, we find that the history of languages is critical to understand their present state., Comment: Main text: 12 pages, 6 figures, 51 references. Supplementary Information: 27 pages, 16 figures, 2 tables

Countries globally trade with tons of waste materials every year, some of which are highly hazardous. This trade admits a network representation of the world-wide waste web, with countries as vertices and flows as directed weighted edges. Here we investigate the main properties of this network by tracking 108 categories of wastes interchanged in the period 2001-2019. Although, most of the hazardous waste was traded between developed nations, a disproportionate asymmetry existed in the flow from developed to developing countries. Using a dynamical model, we simulate how waste stress propagates through the network and affects the countries. We identify 28 countries with low Environmental Performance Index that are at high risk of waste congestion. Therefore, they are at threat of improper handling and disposal of hazardous waste. We find evidence of pollution by heavy metals, by volatile organic compounds and/or by persistent organic pollutants, which are used as chemical fingerprints, due to the improper handling of waste in several of these countries., Comment: Nat Commun (2022). Main manuscript, and supplementary information. Total of 15 figures and 58 pages

Ariel, the Atmospheric Remote-sensing Infrared Exoplanet Large-survey, was adopted as the fourth medium-class mission in ESA's Cosmic Vision programme to be launched in 2029. During its 4-year mission, Ariel will study what exoplanets are made of, how they formed and how they evolve, by surveying a diverse sample of about 1000 extrasolar planets, simultaneously in visible and infrared wavelengths. It is the first mission dedicated to measuring the chemical composition and thermal structures of hundreds of transiting exoplanets, enabling planetary science far beyond the boundaries of the Solar System. The payload consists of an off-axis Cassegrain telescope (primary mirror 1100 mm x 730 mm ellipse) and two separate instruments (FGS and AIRS) covering simultaneously 0.5-7.8 micron spectral range. The satellite is best placed into an L2 orbit to maximise the thermal stability and the field of regard. The payload module is passively cooled via a series of V-Groove radiators; the detectors for the AIRS are the only items that require active cooling via an active Ne JT cooler. The Ariel payload is developed by a consortium of more than 50 institutes from 16 ESA countries, which include the UK, France, Italy, Belgium, Poland, Spain, Austria, Denmark, Ireland, Portugal, Czech Republic, Hungary, the Netherlands, Sweden, Norway, Estonia, and a NASA contribution., Comment: Ariel Definition Study Report, 147 pages. Reviewed by ESA Science Advisory Structure in November 2020. Original document available at: https://www.cosmos.esa.int/documents/1783156/3267291/Ariel_RedBook_Nov2020.pdf/

We consider genuine type IIB string theory (supersymmetric) brane intersections that preserve $(1+1)$D Lorentz symmetry. We provide the full supergravity solutions in their analytic form and discuss their physical properties. The Ansatz for the spacetime dependence of the different brane warp factors goes beyond the harmonic superposition principle. By studying the associated near-horizon geometry, we construct interesting classes of AdS$_3$ vacua in type IIB and highlight their relation to the existing classifications in the literature. Finally, we discuss their holographic properties., Comment: 18 pages

Recent experiments evidence the direct observation of spin waves in chromium trihalides and a gap at the Dirac points of the magnon dispersion in bulk CrI$_3$. However, the topological origin of this feature remains unclear and its emergence at the 2D limit has not yet been proven experimentally. Herein, we perform a fully self-consistent ab initio analysis that supports the presence of topological magnons in chromium trihalides monolayers. Our results confirm the existence of a gap around the K high-symmetry point in the linear magnon dispersion of CrI$_3$, which originates as a direct consequence of intralayer Dzyaloshinskii-Moriya (DM) interaction. In addition, our orbital resolved analysis reveals the microscopic mechanisms that can be exploited using strain engineering to increase the strength of the DM interaction and thus control the gap size in CrI$_3$. This paves the way to the further development of this family of materials as building-blocks for topological magnonics at the limit of miniaturization.

The continuous Multi Scale Entanglement Renormalization Anstaz (cMERA) consists of a variational method which carries out a real space renormalization scheme on the wavefunctionals of quantum field theories. In this work we calculate the entanglement entropy of the half space for a free scalar theory through a Gaussian cMERA circuit. We obtain the correct entropy written in terms of the optimized cMERA variational parameter, the local density of disentanglers. Accordingly, using the entanglement entropy production per unit scale, we study local areas in the bulk of the tensor network in terms of the differential entanglement generated along the cMERA flow. This result spurs us to establish an explicit relation between the cMERA variational parameter and the radial component of a dual AdS geometry through the Ryu-Takayanagi formula. Finally, based on recent formulations of non-Gaussian cMERA circuits, we argue that the entanglement entropy for the half space can be written as an integral along the renormalization scale whose measure is given by the Fisher information metric of the cMERA circuit. Consequently, a straightforward relation between AdS geometry and the Fisher information metric is also established., Comment: 18 pages, 1 figure. Some references added in which v2 is the final version published in Fortschritte der Physik. Progress of Physics

We propose a Leibniz algebra, to be called DD$^+$, which is a generalization of the Drinfel'd double. We find that there is a one-to-one correspondence between a DD$^+$ and a Jacobi--Lie bialgebra, extending the known correspondence between a Lie bialgebra and a Drinfel'd double. We then construct generalized frame fields $E_A{}^M\in\text{O}(D,D)\times\mathbb{R}^+$ satisfying the algebra $\mathcal{L}_{E_A}E_B = - X_{AB}{}^C\,E_C\,$, where $X_{AB}{}^C$ are the structure constants of the DD$^+$ and $\mathcal{L}$ is the generalized Lie derivative in double field theory. Using the generalized frame fields, we propose the Jacobi-Lie T-plurality and show that it is a symmetry of double field theory. We present several examples of the Jacobi-Lie T-plurality with or without Ramond-Ramond fields and the spectator fields., Comment: 30 pages; v2: minor corrections, references added; v3 matches the published version: extended the discussion, an appendix and references added

Bound states in superconductors are expected to exhibit a spatially resolved electron-hole asymmetry which is the hallmark of their quantum nature. This asymmetry manifests as oscillations at the Fermi wavelength, which is usually tiny and thus washed out by thermal broadening or by scattering at defects. Here we demonstrate theoretically and confirm experimentally that, when coupled to magnetic impurities, bound states in a vortex core exhibit an emergent axial electron-hole asymmetry on a much longer scale, set by the coherence length. We study vortices in 2H-NbSe$_2$ and in 2H-NbSe$_{1.8}$S_{0.2}$ with magnetic impurities, characterizing these with detailed Hubbard-corrected density functional calculations. We find that the induced electron-hole imbalance depends on the band character of the superconducting material. Our results open interesting prospects for the study of coupled superconducting bound states.

Three decades of research in molecular nanomagnets have raised their magnetic memories from liquid helium to liquid nitrogen temperature thanks to a wise choice of the magnetic ion and coordination environment. Still, serendipity and chemical intuition played a main role. In order to establish a powerful framework for statistically driven chemical design, we collected chemical and physical data for lanthanide-based nanomagnets, catalogued over 1400 published experiments, developed an interactive dashboard (SIMDAVIS) to visualise the dataset, and applied inferential statistical analysis. Our analysis showed that the Arrhenius energy barrier correlates unexpectedly well with the magnetic memory, as both Orbach and Raman processes can be controlled by vibronic coupling. Indeed, only bis-phthalocyaninato sandwiches and metallocenes, with rigid ligands, consistently present magnetic memory up to high temperature. Analysing magnetostructural correlations, we offer promising strategies for improvement, in particular for the preparation of pentagonal bipyramids, where even "softer" complexes are protected against molecular vibrations., Comment: 109 pages (main text+SI). Related content: interactive dashboard for Single Ion Magnet Data Visualization. https://go.uv.es/rosaleny/SIMDAVIS

Molecular vibrations play a key role in magnetic relaxation processes of molecular spin qubits as they couple to spin states, leading to the loss of quantum information. Direct experimental determination of vibronic coupling is crucial to understand and control the spin dynamics of these nano-objects, which represent the limit of miniaturization for quantum devices. Herein, we measure the vibrational properties of the molecular spin qubit $[$Ho(W$_5$O$_{18}$)$_2]^{9-}$ by means of magneto-infrared spectroscopy. Our results allow us to unravel the vibrational decoherence pathways in combination with $ab$ $initio$ calculations including vibronic coupling. We observe field-induced spectral changes near 63 and 370 cm$^{-1}$ that are modeled in terms of $f$-manifold crystal field excitations activated by odd-symmetry vibrations. The overall extent of vibronic coupling in this system is limited by a transparency window in the phonon density of states that acts to keep the intramolecular vibrations and $M_J$ levels apart. These findings advance the understanding of vibronic coupling in molecular magnets, place significant constraints on the pattern of crystal field levels in these systems, and provide a strategy for designing molecular spin qubits with improved coherence lifetimes., Comment: 22 pages

We compare the spectrum of the stochastic gravitational wave background produced in several models of cosmic strings with the common-spectrum process recently reported by NANOGrav. We discuss theoretical uncertainties in computing such a background, and show that despite such uncertainties, cosmic strings remain a good explanation for the potential signal, but the consequences for cosmic string parameters depend on the model. Superstrings could also explain the signal, but only in a restricted parameter space where their network behavior is effectively identical to that of ordinary cosmic strings., Comment: 15 pages, RevTex