@article{14852, abstract = {The physical conditions giving rise to high escape fractions of ionizing radiation (LyC fesc) in star-forming galaxies – most likely protagonists of cosmic reionization – are not yet fully understood. Using the VLT/MUSE observations of ∼1400 Ly α emitters at 2.9 < z < 6.7, we compare stacked rest-frame UV spectra of candidates for LyC leakers and non-leakers selected based on their Ly α profiles. We find that the stacks of potential LyC leakers, i.e. galaxies with narrow, symmetric Ly α profiles with small peak separation, generally show (i) strong nebular O iii]λ1666, [Si iii]λ1883, and [C iii]λ1907 +C iii]λ1909 emission, indicating a high-ionization state of the interstellar medium (ISM); (ii) high equivalent widths of He iiλ1640 (∼1 − 3 Å), suggesting the presence of hard ionizing radiation fields; (iii) Si ii*λ1533 emission, revealing substantial amounts of neutral hydrogen off the line of sight; (iv) high C ivλλ1548,1550 to [C iii]λ1907 +C iii]λ1909 ratios (C iv/C iii] ≳0.75) , signalling the presence of low column density channels in the ISM. In contrast, the stacks with broad, asymmetric Ly α profiles with large peak separation show weak nebular emission lines, low He iiλ1640 equivalent widths (≲1 Å), and low C iv/C iii] (≲0.25), implying low-ionization states and high-neutral hydrogen column densities. Our results suggest that C iv/C iii] might be sensitive to the physical conditions that govern LyC photon escape, providing a promising tool for identification of ionizing sources among star-forming galaxies in the epoch of reionization.}, author = {Kramarenko, Ivan and Kerutt, J and Verhamme, A and Oesch, P A and Barrufet, L and Matthee, Jorryt J and Kusakabe, H and Goovaerts, I and Thai, T T}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {4}, pages = {9853--9871}, publisher = {Oxford University Press}, title = {{Linking UV spectral properties of MUSE Ly α emitters at z ≳ 3 to Lyman continuum escape}}, doi = {10.1093/mnras/stad3853}, volume = {527}, year = {2024}, } @article{15053, abstract = {Atom-based quantum simulators have had many successes in tackling challenging quantum many-body problems, owing to the precise and dynamical control that they provide over the systems' parameters. They are, however, often optimized to address a specific type of problem. Here, we present the design and implementation of a 6Li-based quantum gas platform that provides wide-ranging capabilities and is able to address a variety of quantum many-body problems. Our two-chamber architecture relies on a robust combination of gray molasses and optical transport from a laser-cooling chamber to a glass cell with excellent optical access. There, we first create unitary Fermi superfluids in a three-dimensional axially symmetric harmonic trap and characterize them using in situ thermometry, reaching temperatures below 20 nK. This allows us to enter the deep superfluid regime with samples of extreme diluteness, where the interparticle spacing is sufficiently large for direct single-atom imaging. Second, we generate optical lattice potentials with triangular and honeycomb geometry in which we study diffraction of molecular Bose-Einstein condensates, and show how going beyond the Kapitza-Dirac regime allows us to unambiguously distinguish between the two geometries. With the ability to probe quantum many-body physics in both discrete and continuous space, and its suitability for bulk and single-atom imaging, our setup represents an important step towards achieving a wide-scope quantum simulator.}, author = {Jin, Shuwei and Dai, Kunlun and Verstraten, Joris and Dixmerias, Maxime and Al Hyder, Ragheed and Salomon, Christophe and Peaudecerf, Bruno and de Jongh, Tim and Yefsah, Tarik}, issn = {2643-1564}, journal = {Physical Review Research}, keywords = {General Physics and Astronomy}, number = {1}, publisher = {American Physical Society}, title = {{Multipurpose platform for analog quantum simulation}}, doi = {10.1103/physrevresearch.6.013158}, volume = {6}, year = {2024}, } @article{14321, abstract = {We demonstrate the possibility of a coupling between the magnetization direction of a ferromagnet and the tilting angle of adsorbed achiral molecules. To illustrate the mechanism of the coupling, we analyze a minimal Stoner model that includes Rashba spin–orbit coupling due to the electric field on the surface of the ferromagnet. The proposed mechanism allows us to study magnetic anisotropy of the system with an extended Stoner–Wohlfarth model and argue that adsorbed achiral molecules can change magnetocrystalline anisotropy of the substrate. Our research aims to motivate further experimental studies of the current-free chirality induced spin selectivity effect involving both enantiomers.}, author = {Al Hyder, Ragheed and Cappellaro, Alberto and Lemeshko, Mikhail and Volosniev, Artem}, issn = {1089-7690}, journal = {The Journal of Chemical Physics}, keywords = {Physical and Theoretical Chemistry, General Physics and Astronomy}, number = {10}, publisher = {AIP Publishing}, title = {{Achiral dipoles on a ferromagnet can affect its magnetization direction}}, doi = {10.1063/5.0165806}, volume = {159}, year = {2023}, } @article{14334, abstract = {Quantum kinetically constrained models have recently attracted significant attention due to their anomalous dynamics and thermalization. In this work, we introduce a hitherto unexplored family of kinetically constrained models featuring conserved particle number and strong inversion-symmetry breaking due to facilitated hopping. We demonstrate that these models provide a generic example of so-called quantum Hilbert space fragmentation, that is manifested in disconnected sectors in the Hilbert space that are not apparent in the computational basis. Quantum Hilbert space fragmentation leads to an exponential in system size number of eigenstates with exactly zero entanglement entropy across several bipartite cuts. These eigenstates can be probed dynamically using quenches from simple initial product states. In addition, we study the particle spreading under unitary dynamics launched from the domain wall state, and find faster than diffusive dynamics at high particle densities, that crosses over into logarithmically slow relaxation at smaller densities. Using a classically simulable cellular automaton, we reproduce the logarithmic dynamics observed in the quantum case. Our work suggests that particle conserving constrained models with inversion symmetry breaking realize so far unexplored dynamical behavior and invite their further theoretical and experimental studies.}, author = {Brighi, Pietro and Ljubotina, Marko and Serbyn, Maksym}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {3}, publisher = {SciPost Foundation}, title = {{Hilbert space fragmentation and slow dynamics in particle-conserving quantum East models}}, doi = {10.21468/scipostphys.15.3.093}, volume = {15}, year = {2023}, } @article{14650, abstract = {We study the out-of-equilibrium quantum dynamics of dipolar polarons, i.e., impurities immersed in a dipolar Bose-Einstein condensate, after a quench of the impurity-boson interaction. We show that the dipolar nature of the condensate and of the impurity results in anisotropic relaxation dynamics, in particular, anisotropic dressing of the polaron. More relevantly for cold-atom setups, quench dynamics is strongly affected by the interplay between dipolar anisotropy and trap geometry. Our findings pave the way for simulating impurities in anisotropic media utilizing experiments with dipolar mixtures.}, author = {Volosniev, Artem and Bighin, Giacomo and Santos, Luis and Peña Ardila, Luisllu A.}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {6}, publisher = {SciPost Foundation}, title = {{Non-equilibrium dynamics of dipolar polarons}}, doi = {10.21468/scipostphys.15.6.232}, volume = {15}, year = {2023}, } @article{14754, abstract = {The large-scale laminar/turbulent spiral patterns that appear in the linearly unstable regime of counter-rotating Taylor–Couette flow are investigated from a statistical perspective by means of direct numerical simulation. Unlike the vast majority of previous numerical studies, we analyse the flow in periodic parallelogram-annular domains, following a coordinate change that aligns one of the parallelogram sides with the spiral pattern. The domain size, shape and spatial resolution have been varied and the results compared with those in a sufficiently large computational orthogonal domain with natural axial and azimuthal periodicity. We find that a minimal parallelogram of the right tilt significantly reduces the computational cost without notably compromising the statistical properties of the supercritical turbulent spiral. Its mean structure, obtained from extremely long time integrations in a co-rotating reference frame using the method of slices, bears remarkable similarity with the turbulent stripes observed in plane Couette flow, the centrifugal instability playing only a secondary role.}, author = {Wang, B. and Mellibovsky, F. and Ayats López, Roger and Deguchi, K. and Meseguer, A.}, issn = {1471-2962}, journal = {Philosophical Transactions of the Royal Society A}, keywords = {General Physics and Astronomy, General Engineering, General Mathematics}, number = {2246}, publisher = {The Royal Society}, title = {{Mean structure of the supercritical turbulent spiral in Taylor–Couette flow}}, doi = {10.1098/rsta.2022.0112}, volume = {381}, year = {2023}, } @article{14773, abstract = {Through a combination of idealized simulations and real-world data, researchers are uncovering how internal feedbacks and large-scale motions influence cloud dynamics.}, author = {Muller, Caroline J and Abramian, Sophie}, issn = {1945-0699}, journal = {Physics Today}, keywords = {General Physics and Astronomy}, number = {5}, publisher = {AIP Publishing}, title = {{The cloud dynamics of convective storm systems}}, doi = {10.1063/pt.3.5234}, volume = {76}, year = {2023}, } @article{14777, abstract = {The effects of the partial V-substitution for Ag on the thermoelectric (TE) properties are investigated for a flexible semiconducting compound Ag2S0.55Se0.45. Density functional theory calculations predict that such a partial V-substitution constructively modifies the electronic structure near the bottom of the conduction band to improve the TE performance. The synthesized Ag1.97V0.03S0.55Se0.45 is found to possess a TE dimensionless figure-of-merit (ZT) of 0.71 at 350 K with maintaining its flexible nature. This ZT value is relatively high in comparison with those reported for flexible TE materials below 360 K. The increase in the ZT value is caused by the enhanced absolute value of the Seebeck coefficient with less significant variation in electrical resistivity. The high ZT value with the flexible nature naturally allows us to employ the Ag1.97V0.03S0.55Se0.45 as a component of flexible TE generators.}, author = {Sato, Kosuke and Singh, Saurabh and Yamazaki, Itsuki and Hirata, Keisuke and Ang, Artoni Kevin R. and Matsunami, Masaharu and Takeuchi, Tsunehiro}, issn = {2158-3226}, journal = {AIP Advances}, keywords = {General Physics and Astronomy}, number = {12}, publisher = {AIP Publishing}, title = {{Improvement of thermoelectric performance of flexible compound Ag2S0.55Se0.45 by means of partial V-substitution for Ag}}, doi = {10.1063/5.0171888}, volume = {13}, year = {2023}, } @article{13197, abstract = {Nominally identical materials exchange net electric charge during contact through a mechanism that is still debated. ‘Mosaic models’, in which surfaces are presumed to consist of a random patchwork of microscopic donor/acceptor sites, offer an appealing explanation for this phenomenon. However, recent experiments have shown that global differences persist even between same-material samples, which the standard mosaic framework does not account for. Here, we expand the mosaic framework by incorporating global differences in the densities of donor/acceptor sites. We develop an analytical model, backed by numerical simulations, that smoothly connects the global and deterministic charge transfer of different materials to the local and stochastic mosaic picture normally associated with identical materials. Going further, we extend our model to explain the effect of contact asymmetries during sliding, providing a plausible explanation for reversal of charging sign that has been observed experimentally.}, author = {Grosjean, Galien M and Waitukaitis, Scott R}, issn = {2475-9953}, journal = {Physical Review Materials}, keywords = {Physics and Astronomy (miscellaneous), General Materials Science}, number = {6}, publisher = {American Physical Society}, title = {{Asymmetries in triboelectric charging: Generalizing mosaic models to different-material samples and sliding contacts}}, doi = {10.1103/physrevmaterials.7.065601}, volume = {7}, year = {2023}, } @article{13274, abstract = {Viscous flows through pipes and channels are steady and ordered until, with increasing velocity, the laminar motion catastrophically breaks down and gives way to turbulence. How this apparently discontinuous change from low- to high-dimensional motion can be rationalized within the framework of the Navier-Stokes equations is not well understood. Exploiting geometrical properties of transitional channel flow we trace turbulence to far lower Reynolds numbers (Re) than previously possible and identify the complete path that reversibly links fully turbulent motion to an invariant solution. This precursor of turbulence destabilizes rapidly with Re, and the accompanying explosive increase in attractor dimension effectively marks the transition between deterministic and de facto stochastic dynamics.}, author = {Paranjape, Chaitanya S and Yalniz, Gökhan and Duguet, Yohann and Budanur, Nazmi B and Hof, Björn}, issn = {1079-7114}, journal = {Physical Review Letters}, keywords = {General Physics and Astronomy}, number = {3}, publisher = {American Physical Society}, title = {{Direct path from turbulence to time-periodic solutions}}, doi = {10.1103/physrevlett.131.034002}, volume = {131}, year = {2023}, } @article{13278, abstract = {We present a numerical analysis of spin-1/2 fermions in a one-dimensional harmonic potential in the presence of a magnetic point-like impurity at the center of the trap. The model represents a few-body analogue of a magnetic impurity in the vicinity of an s-wave superconductor. Already for a few particles we find a ground-state level crossing between sectors with different fermion parities. We interpret this crossing as a few-body precursor of a quantum phase transition, which occurs when the impurity "breaks" a Cooper pair. This picture is further corroborated by analyzing density-density correlations in momentum space. Finally, we discuss how the system may be realized with existing cold-atoms platforms.}, author = {Rammelmüller, Lukas and Huber, David and Čufar, Matija and Brand, Joachim and Hammer, Hans-Werner and Volosniev, Artem}, issn = {2542-4653}, journal = {SciPost Physics}, keywords = {General Physics and Astronomy}, number = {1}, publisher = {SciPost Foundation}, title = {{Magnetic impurity in a one-dimensional few-fermion system}}, doi = {10.21468/scipostphys.14.1.006}, volume = {14}, year = {2023}, } @article{13346, abstract = {The self-assembly of nanoparticles driven by small molecules or ions may produce colloidal superlattices with features and properties reminiscent of those of metals or semiconductors. However, to what extent the properties of such supramolecular crystals actually resemble those of atomic materials often remains unclear. Here, we present coarse-grained molecular simulations explicitly demonstrating how a behavior evocative of that of semiconductors may emerge in a colloidal superlattice. As a case study, we focus on gold nanoparticles bearing positively charged groups that self-assemble into FCC crystals via mediation by citrate counterions. In silico ohmic experiments show how the dynamically diverse behavior of the ions in different superlattice domains allows the opening of conductive ionic gates above certain levels of applied electric fields. The observed binary conductive/nonconductive behavior is reminiscent of that of conventional semiconductors, while, at a supramolecular level, crossing the “band gap” requires a sufficient electrostatic stimulus to break the intermolecular interactions and make ions diffuse throughout the superlattice’s cavities.}, author = {Lionello, Chiara and Perego, Claudio and Gardin, Andrea and Klajn, Rafal and Pavan, Giovanni M.}, issn = {1936-086X}, journal = {ACS Nano}, keywords = {General Physics and Astronomy, General Engineering, General Materials Science}, number = {1}, pages = {275--287}, publisher = {American Chemical Society}, title = {{Supramolecular semiconductivity through emerging ionic gates in ion–nanoparticle superlattices}}, doi = {10.1021/acsnano.2c07558}, volume = {17}, year = {2023}, } @article{13443, abstract = {The ages of solar-like stars have been at the center of many studies such as exoplanet characterization or Galactic-archeology. While ages are usually computed from stellar evolution models, relations linking ages to other stellar properties, such as rotation and magnetic activity, have been investigated. With the large catalog of 55,232 rotation periods, Prot, and photometric magnetic activity index, Sph from Kepler data, we have the opportunity to look for such magneto-gyro-chronology relations. Stellar ages are obtained with two stellar evolution codes that include treatment of angular momentum evolution, hence using Prot as input in addition to classical atmospheric parameters. We explore two different ways of predicting stellar ages on three subsamples with spectroscopic observations: solar analogs, late-F and G dwarfs, and K dwarfs. We first perform a Bayesian analysis to derive relations between Sph and ages between 1 and 5 Gyr, and other stellar properties. For late-F and G dwarfs, and K dwarfs, the multivariate regression favors the model with Prot and Sph with median differences of 0.1% and 0.2%, respectively. We also apply Machine Learning techniques with a Random Forest algorithm to predict ages up to 14 Gyr with the same set of input parameters. For late-F, G and K dwarfs together, predicted ages are on average within 5.3% of the model ages and improve to 3.1% when including Prot. These are very promising results for a quick age estimation for solar-like stars with photometric observations, especially with current and future space missions.}, author = {Mathur, Savita and Claytor, Zachary R. and Santos, Ângela R. G. and García, Rafael A. and Amard, Louis and Bugnet, Lisa Annabelle and Corsaro, Enrico and Bonanno, Alfio and Breton, Sylvain N. and Godoy-Rivera, Diego and Pinsonneault, Marc H. and van Saders, Jennifer}, issn = {1538-4357}, journal = {The Astrophysical Journal}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {2}, publisher = {American Astronomical Society}, title = {{Magnetic activity evolution of solar-like stars. I. Sph–age relation derived from Kepler observations}}, doi = {10.3847/1538-4357/acd118}, volume = {952}, year = {2023}, } @article{13449, abstract = {Stars strongly impact their environment, and shape structures on all scales throughout the universe, in a process known as "feedback." Due to the complexity of both stellar evolution and the physics of larger astrophysical structures, there remain many unanswered questions about how feedback operates and what we can learn about stars by studying their imprint on the wider universe. In this white paper, we summarize discussions from the Lorentz Center meeting "Bringing Stellar Evolution and Feedback Together" in 2022 April and identify key areas where further dialog can bring about radical changes in how we view the relationship between stars and the universe they live in.}, author = {Geen, Sam and Agrawal, Poojan and Crowther, Paul A. and Keller, B. W. and de Koter, Alex and Keszthelyi, Zsolt and van de Voort, Freeke and Ali, Ahmad A. and Backs, Frank and Bonne, Lars and Brugaletta, Vittoria and Derkink, Annelotte and Ekström, Sylvia and Fichtner, Yvonne A. and Grassitelli, Luca and Götberg, Ylva Louise Linsdotter and Higgins, Erin R. and Laplace, Eva and You Liow, Kong and Lorenzo, Marta and McLeod, Anna F. and Meynet, Georges and Newsome, Megan and André Oliva, G. and Ramachandran, Varsha and Rey, Martin P. and Rieder, Steven and Romano-Díaz, Emilio and Sabhahit, Gautham and Sander, Andreas A. C. and Sarwar, Rafia and Stinshoff, Hanno and Stoop, Mitchel and Szécsi, Dorottya and Trebitsch, Maxime and Vink, Jorick S. and Winch, Ethan}, issn = {1538-3873}, journal = {Publications of the Astronomical Society of the Pacific}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {1044}, publisher = {IOP Publishing}, title = {{Bringing stellar evolution and feedback together: Summary of proposals from the Lorentz Center workshop}}, doi = {10.1088/1538-3873/acb6b5}, volume = {135}, year = {2023}, } @article{13450, abstract = {In previous work, we identified a population of 38 cool and luminous variable stars in the Magellanic Clouds and examined 11 in detail in order to classify them as either Thorne–Żytkow objects (TŻOs; red supergiants with a neutron star cores) or super-asymptotic giant branch (sAGB) stars (the most massive stars that will not undergo core collapse). This population includes HV 2112, a peculiar star previously considered in other works to be either a TŻO or high-mass asymptotic giant branch (AGB) star. Here we continue this investigation, using the kinematic and radio environments and local star formation history of these stars to place constraints on the age of the progenitor systems and the presence of past supernovae. These stars are not associated with regions of recent star formation, and we find no evidence of past supernovae at their locations. Finally, we also assess the presence of heavy elements and lithium in their spectra compared to red supergiants. We find strong absorption in Li and s-process elements compared to RSGs in most of the sample, consistent with sAGB nucleosynthesis, while HV 2112 shows additional strong lines associated with TŻO nucleosynthesis. Coupled with our previous mass estimates, the results are consistent with the stars being massive (∼4–6.5 M⊙) or sAGB (∼6.5–12 M⊙) stars in the thermally pulsing phase, providing crucial observations of the transition between low- and high-mass stellar populations. HV 2112 is more ambiguous; it could either be a maximally massive sAGB star, or a TŻO if the minimum mass for stability extends down to ≲13 M⊙.}, author = {O‘Grady, Anna J. G. and Drout, Maria R. and Gaensler, B. M. and Kochanek, C. S. and Neugent, Kathryn F. and Doherty, Carolyn L. and Speagle, Joshua S. and Shappee, B. J. and Rauch, Michael and Götberg, Ylva Louise Linsdotter and Ludwig, Bethany and Thompson, Todd A.}, issn = {1538-4357}, journal = {The Astrophysical Journal}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {1}, publisher = {American Astronomical Society}, title = {{Cool, luminous, and highly variable stars in the Magellanic Clouds. II. Spectroscopic and environmental analysis of Thorne–Żytkow object and super-AGB star candidates}}, doi = {10.3847/1538-4357/aca655}, volume = {943}, year = {2023}, } @article{13989, abstract = {Characterizing and controlling entanglement in quantum materials is crucial for the development of next-generation quantum technologies. However, defining a quantifiable figure of merit for entanglement in macroscopic solids is theoretically and experimentally challenging. At equilibrium the presence of entanglement can be diagnosed by extracting entanglement witnesses from spectroscopic observables and a nonequilibrium extension of this method could lead to the discovery of novel dynamical phenomena. Here, we propose a systematic approach to quantify the time-dependent quantum Fisher information and entanglement depth of transient states of quantum materials with time-resolved resonant inelastic x-ray scattering. Using a quarter-filled extended Hubbard model as an example, we benchmark the efficiency of this approach and predict a light-enhanced many-body entanglement due to the proximity to a phase boundary. Our work sets the stage for experimentally witnessing and controlling entanglement in light-driven quantum materials via ultrafast spectroscopic measurements.}, author = {Hales, Jordyn and Bajpai, Utkarsh and Liu, Tongtong and Baykusheva, Denitsa Rangelova and Li, Mingda and Mitrano, Matteo and Wang, Yao}, issn = {2041-1723}, journal = {Nature Communications}, keywords = {General Physics and Astronomy, General Biochemistry, Genetics and Molecular Biology, General Chemistry, Multidisciplinary}, publisher = {Springer Nature}, title = {{Witnessing light-driven entanglement using time-resolved resonant inelastic X-ray scattering}}, doi = {10.1038/s41467-023-38540-3}, volume = {14}, year = {2023}, } @article{13990, abstract = {Many-body entanglement in condensed matter systems can be diagnosed from equilibrium response functions through the use of entanglement witnesses and operator-specific quantum bounds. Here, we investigate the applicability of this approach for detecting entangled states in quantum systems driven out of equilibrium. We use a multipartite entanglement witness, the quantum Fisher information, to study the dynamics of a paradigmatic fermion chain undergoing a time-dependent change of the Coulomb interaction. Our results show that the quantum Fisher information is able to witness distinct signatures of multipartite entanglement both near and far from equilibrium that are robust against decoherence. We discuss implications of these findings for probing entanglement in light-driven quantum materials with time-resolved optical and x-ray scattering methods.}, author = {Baykusheva, Denitsa Rangelova and Kalthoff, Mona H. and Hofmann, Damian and Claassen, Martin and Kennes, Dante M. and Sentef, Michael A. and Mitrano, Matteo}, issn = {1079-7114}, journal = {Physical Review Letters}, keywords = {General Physics and Astronomy}, number = {10}, publisher = {American Physical Society}, title = {{Witnessing nonequilibrium entanglement dynamics in a strongly correlated fermionic chain}}, doi = {10.1103/physrevlett.130.106902}, volume = {130}, year = {2023}, } @article{14032, abstract = {Arrays of Josephson junctions are governed by a competition between superconductivity and repulsive Coulomb interactions, and are expected to exhibit diverging low-temperature resistance when interactions exceed a critical level. Here we report a study of the transport and microwave response of Josephson arrays with interactions exceeding this level. Contrary to expectations, we observe that the array resistance drops dramatically as the temperature is decreased—reminiscent of superconducting behaviour—and then saturates at low temperature. Applying a magnetic field, we eventually observe a transition to a highly resistive regime. These observations can be understood within a theoretical picture that accounts for the effect of thermal fluctuations on the insulating phase. On the basis of the agreement between experiment and theory, we suggest that apparent superconductivity in our Josephson arrays arises from melting the zero-temperature insulator.}, author = {Mukhopadhyay, Soham and Senior, Jorden L and Saez Mollejo, Jaime and Puglia, Denise and Zemlicka, Martin and Fink, Johannes M and Higginbotham, Andrew P}, issn = {1745-2481}, journal = {Nature Physics}, keywords = {General Physics and Astronomy}, pages = {1630--1635}, publisher = {Springer Nature}, title = {{Superconductivity from a melted insulator in Josephson junction arrays}}, doi = {10.1038/s41567-023-02161-w}, volume = {19}, year = {2023}, } @article{14103, abstract = {Observations of individual massive stars, super-luminous supernovae, gamma-ray bursts, and gravitational wave events involving spectacular black hole mergers indicate that the low-metallicity Universe is fundamentally different from our own Galaxy. Many transient phenomena will remain enigmatic until we achieve a firm understanding of the physics and evolution of massive stars at low metallicity (Z). The Hubble Space Telescope has devoted 500 orbits to observing ∼250 massive stars at low Z in the ultraviolet (UV) with the COS and STIS spectrographs under the ULLYSES programme. The complementary X-Shooting ULLYSES (XShootU) project provides an enhanced legacy value with high-quality optical and near-infrared spectra obtained with the wide-wavelength coverage X-shooter spectrograph at ESO’s Very Large Telescope. We present an overview of the XShootU project, showing that combining ULLYSES UV and XShootU optical spectra is critical for the uniform determination of stellar parameters such as effective temperature, surface gravity, luminosity, and abundances, as well as wind properties such as mass-loss rates as a function of Z. As uncertainties in stellar and wind parameters percolate into many adjacent areas of astrophysics, the data and modelling of the XShootU project is expected to be a game changer for our physical understanding of massive stars at low Z. To be able to confidently interpret James Webb Space Telescope spectra of the first stellar generations, the individual spectra of low-Z stars need to be understood, which is exactly where XShootU can deliver.}, author = {Vink, Jorick S. and Mehner, A. and Crowther, P. A. and Fullerton, A. and Garcia, M. and Martins, F. and Morrell, N. and Oskinova, L. M. and St-Louis, N. and ud-Doula, A. and Sander, A. A. C. and Sana, H. and Bouret, J.-C. and Kubátová, B. and Marchant, P. and Martins, L. P. and Wofford, A. and van Loon, J. Th. and Grace Telford, O. and Götberg, Ylva Louise Linsdotter and Bowman, D. M. and Erba, C. and Kalari, V. M. and Abdul-Masih, M. and Alkousa, T. and Backs, F. and Barbosa, C. L. and Berlanas, S. R. and Bernini-Peron, M. and Bestenlehner, J. M. and Blomme, R. and Bodensteiner, J. and Brands, S. A. and Evans, C. J. and David-Uraz, A. and Driessen, F. A. and Dsilva, K. and Geen, S. and Gómez-González, V. M. A. and Grassitelli, L. and Hamann, W.-R. and Hawcroft, C. and Herrero, A. and Higgins, E. R. and John Hillier, D. and Ignace, R. and Istrate, A. G. and Kaper, L. and Kee, N. D. and Kehrig, C. and Keszthelyi, Z. and Klencki, J. and de Koter, A. and Kuiper, R. and Laplace, E. and Larkin, C. J. K. and Lefever, R. R. and Leitherer, C. and Lennon, D. J. and Mahy, L. and Maíz Apellániz, J. and Maravelias, G. and Marcolino, W. and McLeod, A. F. and de Mink, S. E. and Najarro, F. and Oey, M. S. and Parsons, T. N. and Pauli, D. and Pedersen, M. G. and Prinja, R. K. and Ramachandran, V. and Ramírez-Tannus, M. C. and Sabhahit, G. N. and Schootemeijer, A. and Reyero Serantes, S. and Shenar, T. and Stringfellow, G. S. and Sudnik, N. and Tramper, F. and Wang, L.}, issn = {1432-0746}, journal = {Astronomy & Astrophysics}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, publisher = {EDP Sciences}, title = {{X-shooting ULLYSES: Massive stars at low metallicity. I. Project description}}, doi = {10.1051/0004-6361/202245650}, volume = {675}, year = {2023}, } @article{14104, abstract = {Thorne–Żytkow objects (TŻO) are potential end products of the merger of a neutron star with a non-degenerate star. In this work, we have computed the first grid of evolutionary models of TŻOs with the MESA stellar evolution code. With these models, we predict several observational properties of TŻOs, including their surface temperatures and luminosities, pulsation periods, and nucleosynthetic products. We expand the range of possible TŻO solutions to cover 3.45≲log(Teff/K)≲3.65 and 4.85≲log(L/L⊙)≲5.5⁠. Due to the much higher densities our TŻOs reach compared to previous models, if TŻOs form we expect them to be stable over a larger mass range than previously predicted, without exhibiting a gap in their mass distribution. Using the GYRE stellar pulsation code we show that TŻOs should have fundamental pulsation periods of 1000–2000 d, and period ratios of ≈0.2–0.3. Models computed with a large 399 isotope fully coupled nuclear network show a nucleosynthetic signal that is different to previously predicted. We propose a new nucleosynthetic signal to determine a star’s status as a TŻO: the isotopologues 44TiO2 and 44TiO⁠, which will have a shift in their spectral features as compared to stable titanium-containing molecules. We find that in the local Universe (∼SMC metallicities and above) TŻOs show little heavy metal enrichment, potentially explaining the difficulty in finding TŻOs to-date.}, author = {Farmer, R and Renzo, M and Götberg, Ylva Louise Linsdotter and Bellinger, E and Justham, S and de Mink, S E}, issn = {1365-2966}, journal = {Monthly Notices of the Royal Astronomical Society}, keywords = {Space and Planetary Science, Astronomy and Astrophysics}, number = {2}, pages = {1692--1709}, publisher = {Oxford University Press}, title = {{Observational predictions for Thorne–Żytkow objects}}, doi = {10.1093/mnras/stad1977}, volume = {524}, year = {2023}, }