Strongly Correlated Electrons
Effects of nonlocal interactions on s- and d-wave superconducting correlations in the extended Hubbard model
Pavol Farkasovsky
We investigate the influence of nonlocal interactions on superconducting correlations within the extended Hubbard model. In addition to the on-site Coulomb interaction and nearest-neighbor hopping, we include next-nearest-neighbor hopping together with several physically relevant nonlocal terms, namely nearest-neighbor Coulomb interaction, correlated hopping, exchange interaction, and pair hopping. Using Lanczos exact diagonalization on a $4\times4$ cluster, supported by projector
quantum Monte Carlo simulations for selected parameter regimes, we analyze pairing correlations in both the s- and d-wave channels. We demonstrate that nonlocal interactions exert a highly nontrivial and
symmetry-dependent influence on superconducting correlations. While the on-site repulsion in cooperation with next-nearest-neighbor hopping enhances d-wave pairing tendencies, correlated hopping and nearest-neighbor Coulomb interaction strongly promote s-wave correlations, whereas exchange and pair-hopping interactions can efficiently suppress superconductivity beyond relatively small critical strengths. When all nonlocal interactions are considered simultaneously, the resulting phase diagrams reveal a complex interplay and competition between different pairing
symmetries. Our results highlight the crucial role of extended interactions in shaping the pairing landscape of strongly correlated systems and demonstrate that a comprehensive treatment beyond the minimal Hubbard model is essential for a realistic description of unconventional superconductivity.
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Superconductivity
Majorana modes in helical altermagnet without net magnetism and spin-orbit coupling
Xing-Jian Yi, Yue Mao, Cheng-Ming Miao et al. (+1 more)
We propose a scheme to realize topological
superconductor and Majorana bound states (MBSs) in a one-dimensional metal nanowire on the surface of a helical altermagnet and in proximity to an s-wave
superconductor, removing the requirement of conventional
spin-orbit coupling and net magnetism. Through gauge transformation, we demonstrate that the helical frame naturally induces
spin-momentum locking while the altermagnetism breaks time-reversal
symmetry. The topological superconducting phase is well tuned by chemical potential, altermagnet strength, and helical frequency. Besides, our transport calculation results reveal quantized conductance signatures: a 2e2/h zero-bias peak at nanowire ends and a 4e2/h tunneling conductance at the domain wall of nanowires with opposite chirality, detected via metal lead and scanning tunneling microscopy, respectively. Our research offers new perspectives on finding MBSs.
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All authors Xing-Jian Yi, Yue Mao, Cheng-Ming Miao, Qing-Feng Sun
Nuclear Experiment
Measurements of charged-particle pseudorapidity and transverse momentum distributions in O+O and Ne+Ne collisions at $\sqrt{s_{_\text{NN}}} = 5.36$ TeV with the ATLAS detector
ATLAS Collaboration
Measurements of charged-particle transverse momentum spectra, multiplicity, and mean transverse momentum are presented as a function of pseudorapidity and collision centrality in O+O and Ne+Ne collisions at $\sqrt{s_{_\text{NN}}}= 5.36$ TeV using 27.7 $\mu\text{b}^{-1}$ and 53.1 $\mu\text{b}^{-1}$ data sets recorded by the ATLAS experiment at the LHC. The collision centrality is characterized by the total transverse energy measured in the ATLAS forward calorimeters. The kinematics of charged particles are reconstructed with the inner detector over the fiducial pseudorapidity and transverse momentum ranges $|\eta|<2.5$ and $0.27 < p_{\text{T}} < 5$ GeV using data from the ATLAS inner detector. The per-event charged-particle pseudorapidity density $dn/d\eta$ and mean transverse momentum $\langle p_{\text{T}}\rangle$ are measured over this fiducial range as a function of $\eta$. The results are reported in 5%-wide centrality intervals covering the 5-80% centrality range, and in 1%-wide intervals covering the 0-5% centrality range. Invariant per-event yields are evaluated as a function of $\eta$ and $p_{\text{T}}$. Their $p_{\text{T}}$ dependence is fitted to estimate extrapolated $dn/d\eta$ and $\langle p_{\text{T}}\rangle$ values over $0 < p_{\text{T}} < 5$ GeV. To evaluate the impact of using pseudorapidity instead of rapidity, measurements are also performed as a function of rapidity computed using a pion mass hypothesis. The fiducial and extrapolated results are compared with hydrodynamic calculations.
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Materials Science
On representation of macroscopic crack in periodic fine-scale discrete mechanical models
Jan Raisinger and Jan Eliáš
In multiscale modeling of heterogeneous softening materials, boundary conditions (BC) in the fine-scale model strongly influence the strain localization pattern and the macroscopic response. For rectilinear models (e.g., squares or cubes), standard Periodic BCs produce artificially ductile behavior with excessive energy dissipation when the localization band inclination does not match the periodicity directions. Recently proposed Tessellation and Percolation-path-aligned BCs promise to address this by adapting the periodicity frame to align with the evolving localization bands. Alternatively, spherical/circular models provide an orientation independent response by design. Unfortunately, the standard Periodic BCs do not allow development of proper localization band crossing spherical model's boundaries. A recently proposed modification addresses this by adding a displacement jump to the spherical periodic BCs. This study evaluates the applicability of these novel BCs to a mesoscale discrete particle model of concrete. Two-dimensional square and circular models under uniaxial tension with different loading directions are analyzed, with the selected approaches extended to three-dimensional cube models. Results show that Percolation-path-aligned BCs exhibit major shortcomings: they can lead to multiple localization bands due to uneven straining of the two boundary sections and their weakly constrained section can be prone to spurious strain localization. In contrast, Tessellation BCs consistently yield a well-defined localization band, whose length is determined solely by the model geometry, making it straightforward to account for in post-processing. Periodic boundary conditions augmented with a displacement jump applied to a circular model sometimes incorrect produce crack patterns similar to those under the standard Periodic BCs.
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Earth and Planetary Astrophysics
Geophysical and atmospheric implications of $f$O$_{2}$-dependent melting on rocky exoplanets
Mariana Sastre, Tim Lichtenberg, Laurent Soucasse et al. (+3 more)
The geochemical
evolution of long-lived magma oceans is strongly regulated by volatile exchange between the molten mantle and the atmosphere. For
planets inside the runaway-greenhouse limit, this coupled
evolution can persist for billions of years. However, most existing studies assume Earth-like (oxidized) conditions and neglect the influence of redox state on melt thermodynamics and volatile release. We quantified how experimentally derived, oxygen-fugacity-dependent melting curves implemented within the coupled interior-atmosphere framework PROTEUS propagate into the thermal structure, melt fraction, and rheological
evolution of rocky
exoplanet interiors, applying this to the short-period super-Earth GJ 1132 b. We found strongly non-linear thermal responses to variations in melting curves. In volatile-poor systems, reduced melting curves promote earlier deep-mantle crystallisation relative to oxidised and Earth-like cases, favouring late-stage surface magma oceans sustained by greenhouse warming, while oxidized melting curves maintain higher melt fractions and a vertically extended magma ocean. Reduced mantles produce massive H$_2$-CO-rich atmospheres; oxidized mantles favour thinner H$_2$O-CO$_2$ envelopes. In volatile-rich systems, the interior reaches radiative
equilibrium at high melt fractions, sustaining a steady-state global magma ocean in which melting curve variations do not significantly influence solidification timing. This indicates a hierarchical control: volatile inventory and surface oxygen fugacity act as the primary regulators of thermal state, while oxygen-fugacity-dependent melting relations provide a secondary modulation. These contrasting regimes produce distinct atmospheric compositions and formation timescales, offering testable spectral predictions for close-in rocky
exoplanets evaluable with forthcoming JWST observations.
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All authors Mariana Sastre, Tim Lichtenberg, Laurent Soucasse, Dan J. Bower, Harrison Nicholls, Inga Kamp
General Relativity and Quantum Cosmology
The auxiliary-metric formulation of Born-Infeld New Massive Gravity
Bayram Tekin
Born-Infeld New Massive
Gravity (BINMG) completes New Massive
Gravity to all orders in
curvature through the determinant of the metric shifted by the Einstein tensor. We recast it with an independent auxiliary metric $q_{\mu\nu}$, whose algebraic equation of motion $q_{\mu\nu}=g_{\mu\nu}+\frac{\sigma}{m^2}G_{\mu\nu}(g)$ recovers the determinant action exactly on the regular branch and resums the infinite
curvature series into a single relation. In the densitized variable $P^{\mu\nu}=\sqrt{-q}\,q^{\mu\nu}$ the three-dimensional action is
polynomial, with all derivative dependence carried by the coupling $P^{\mu\nu}G_{\mu\nu}(g)$. The formulation makes known properties follow with substantially less
algebra: the unique
vacuum follows in one line, and the quadratic action yields a single Pauli-Fierz massive
spin-2 field with the Fierz-Pauli tuning generated rather than imposed. On locally AdS backgrounds the conserved charges, BTZ mass and angular momentum, central charge, and
entropy reduce to the Einstein results times a common factor. The formulation also isolates the nonlinear degree-of-freedom problem in the right variables, leaving the full Dirac count to separate work.
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Quantum Physics
Mitigating Trotter Errors via Post-Processed Symmetry Restoration
Sangjin Lee and Sangkook Choi
Quantum simulation is a powerful tool for exploring complex
quantum many-body systems such as condensed matter physics and gauge theories. Trotterization, which approximates the ideal time
evolution operator by decomposing it into a sequence of local gate operations, is one of the most widely used
quantum simulation
algorithms. However, such Trotterized implementations generally fail to preserve the
symmetries of the target
Hamiltonian during compilation. As a result, they can drive
quantum states out of symmetrically allowed subspaces, leading to unphysical dynamics and
symmetry-violating algorithmic errors. In this work, we propose a
symmetry-based Trotter error mitigation protocol using classical post-processing. By applying
symmetry transformations to the initial state or interleaving them between discrete Trotter layers, and then averaging an ensemble of the resulting measurement outcomes via classical post-processing, our method systematically projects out the
symmetry-violating components of the Trotter error while leaving the ideal dynamics unchanged. Importantly, this framework naturally accommodates non-local spatial
symmetries and anti-
unitary operations such as time reversal, which are difficult or impossible to implement directly with hardware-native
quantum gates. We
benchmark our protocol on the one-dimensional XY model and the one-dimensional Schwinger model. In the XY model, enforcing reflection
symmetry suppresses the leading-order Trotter error, whereas in the Schwinger model, interleaving gauge transformations between Trotter layers enables gauge-twirling effectively to reduce unphysical violations of local Gauss's law. These results demonstrate that
symmetry-based post-processing provides a depth-preserving route to substantially improving the fidelity of Trotterized
quantum simulations on near-term devices.
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Quantum Physics
Random Projections for Multi-Copy Quantum Algorithms
Xiaoyu Liu, Jordi Tura and Johannes Knörzer
Estimating nonlinear properties of
quantum states is a central task in
quantum information science. Multivariate traces, $\mathrm{tr}(\rho_1 \cdots \rho_K)$, and nonlinear observables such as $\mathrm{tr}(\rho^K)$, for integer $K$, can be accessed through collective measurements on multiple state copies, but standard protocols based on swap tests require coherent operations on the full
Hilbert space and become experimentally unfeasible for large systems. In this work, we introduce a framework for multi-copy measurements based on random projections onto lower-dimensional subspaces prior to the collective measurement, which is then performed only on the reduced
Hilbert space. This procedure yields a tunable tradeoff between coherent
quantum resources and statistical sampling overhead, allowing the amount of coherent processing to be matched to the capabilities of the underlying hardware. We derive explicit formulas relating the Haar-averaged projected moments to multivariate traces of the original states and analyze the sampling overhead induced by the projection procedure. Specifically, after compressing an $n$-
qubit state to a reduced $q$-
qubit subspace, estimating $\mathrm{tr}(\rho^K)$ requires approximately $O(2^{(n-q)(K-1)})$ copies of $\rho$, with each
qubit projected out increasing the sampling cost by a factor of $2^{K-1}$. Our results establish how coherent multi-copy operations can be traded for additional state copies, enabling multi-copy
quantum protocols to be optimized for the available hardware resources.
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Statistical Mechanics · Cross-listed from cs.AI
Thermodynamic Measure of Intelligence
Ishanu Chattopadhyay
Can intelligence be measured? We propose that intelligence can be defined as the lawful amplification of rare but valid futures: a system increases the probability of outcomes that would be unlikely under passive dynamics but remain admissible under the constraints of the domain. We start with the premise that an intelligent system must model the world and its own place within it. Because the system is part of the world it models, this leads naturally to recursive self-simulation: the system represents futures in which its own actions are part of the trajectory. Our central results give a necessity statement and a conditional near-sufficiency statement connecting this architecture to a precise thermodynamic measure of lawful amplification of rare-valid futures: high rare-valid lift is impossible unless the internal simulation identifies rare-valid futures with high fidelity; conversely, when rare-valid fidelity is high and the simulation contains an effective policy, the achievable lift approaches the actuation-limited optimum. Thus recursive self-simulation is not merely a plausible feature of intelligence but, under the stated assumptions, is necessary and nearly sufficient for high thermodynamic intelligence. The resulting framework makes intelligence measurable on a universal scale, from passive matter and feedback controllers, large
language models, and humans as text generators to Maxwell-demon-like information engines.
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Earth and Planetary Astrophysics
TOI-2147 b and TOI-6019 b: Two eccentric warm Jupiters detected and characterized with TESS and MaHPS
Luis Thomas, Louise D. Nielsen, Hanna Kellermann et al. (+36 more)
The population of Jupiter-sized
exoplanets with orbital periods between 10 and 200 days (WJs) exhibits a broad range of orbital eccentricities and system architectures, suggesting a diversity of formation and migration pathways. In this work, we report the detection and characterization of two new eccentric WJs, TOI-2147 b and TOI-6019 b, initially identified as
planet candidates by the Transiting
Exoplanet Survey Satellite (TESS). We combined TESS photometry with ground-based follow-up observations, including multiband photometry from LCOGT and MuSCAT2, high-angular-resolution speckle imaging, and high-precision radial velocity measurements from the high-resolution Manfred Hirt
Planet Finder Spectrograph (MaHPS). Using these data, we were able to confirm the planetary nature of both candidates. TOI-2147 b has a radius of $10.5 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $116 \pm 22\,\mathrm{M}_\oplus$. It orbits its slightly metal-poor ($\mathrm{[Fe/H]} = -0.29^{+0.07}_{-0.08}$) G-type host
star on an eccentric orbit ($e = 0.29 \pm 0.07$) with a period of 26.2 days. TOI-6019 b has a radius of $12.3 \pm 0.3\,\mathrm{R}_\oplus$ and a mass of $149 \pm 15\,\mathrm{M}_\oplus$. It orbits a slightly evolved,
solar-
metallicity G-type sub-
giant with a period of 14.5 days on a significantly eccentric orbit ($e = 0.48^{+0.05}_{-0.04}$). Both
planets have bulk densities below that of Jupiter, indicating mildly inflated radii, with interior structure modeling using GASTLI. This suggests that
tidal heating from the nonzero eccentricities likely contributes to this inflation and disfavors large atmospheric metal enrichment. No significant signals from additional companions were detected in the radial velocity time series or transit timing variations. Together with the elevated eccentricities, this is consistent with a high-eccentricity migration origin for both systems.
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All authors Luis Thomas, Louise D. Nielsen, Hanna Kellermann, Bibiana Prinoth, Yutong Liu, Elif Zeynep Özden, Arno Riffeser, Claus Gössl, Frank Grupp, Jerome de Leon, Karen A. Collins, Allyson Bieryla, Lorena Acuña-Aguirre, Keith Baka, Malte Busmann, David R. Ciardi, Catherine A. Clark, Juliana Ehrhardt, Mark E. Everett, Akihiko Fukui, Jan-Vincent Harre, Keisuke Isogai, Yanxi Li, Felipe Murgas, Norio Narita, Enric Palle, Hannu Parviainen, Jan-Niklas Pippert, Christoph Ries, Boris S. Safonov, Thomas Schäfer, Michael Schmidt, Richard P. Schwarz, Laura Schöller, Gregorg Srdoc, Ivan A. Strakhov, Suzanne Taylor, Wenjie Zhou, Raphael Zöller
High Energy Physics (Phenomenology)
Addressing uncertainties of model predictions for extensive air showers initiated by high energy cosmic rays
Sergey Ostapchenko, Tanguy Pierog and Günter Sigl
A new Monte Carlo generator of hadronic collisions, QGSb, is applied for studying model uncertainties regarding calculations of the development of extensive air showers (EAS) initiated by interactions of high energy
cosmic rays in the atmosphere. More specifically, we investigate possibilities to modify the model predictions for two EAS characteristics mostly used in experimental studies of
cosmic ray composition: air shower maximum depth and the
muon number at ground level. For all the considered modifications of the model, we discuss in some detail the underlying physics mechanisms and investigate the impact of the changes, regarding a comparison of the model results to relevant accelerator data.
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High Energy Physics (Theory)
Higher-loop wormhole length in sine-dilaton gravity from DSSYK Krylov complexity
Eleonora Alfinito and Matteo Beccaria
The
quantum wormhole length in sine-dilaton
gravity has been shown to equal the Krylov spread complexity in the double-scaled SYK model. In the infinite temperature limit, we compute the five-loop semiclassical expansion of DSSYK complexity by singular perturbation of the operator Liouville-type equations of motion, extending the existing one-loop results. The same method is applied to evaluate the Krylov variance and third-order cumulant, related to the connected two- and three-point functions of the length operator at coincident points. The small- and large-time behaviour of these observables is also studied. In particular, for the large-time slope of the wormhole linear growth, we determine the all-order resummation of the perturbative series, and the leading non-perturbative corrections.
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Nuclear Experiment
Probing Strange-Quark Hadronization via (Multi-)Strange Hadron Multiplicity Distributions in Small Collision Systems with ALICE
Sara Pucillo
Strangeness enhancement is defined as the increased relative production of strange
hadrons in heavy-ion collisions compared to
proton–
proton (pp) interactions. It was originally proposed as one of the signatures of
quark–
gluon plasma (QGP) formation. At the LHC, the ALICE experiment observed that strange-
hadron-to-pion yield ratios rise with increasing charged-particle multiplicity at midrapidity, independently of collision energy ($\sqrt{s}$) and system size, from pp to p–Pb and up to Pb–Pb collisions. To gain deeper insight into the mechanisms of strangeness production, the ALICE collaboration has measured the probability distribution of producing a given number of strange particles ($K^{0}_{S}$, $\Lambda$, $\Xi$, and $\Omega$) of the same species per event in pp collisions at $\sqrt{s}~=~5.02$ TeV. This measurement extends the study of strangeness production beyond the mean particle yield by employing, for the first time, a technique based on event-by-event particle counting. It provides a new test bench for production mechanisms, probing events with large imbalances between strange and non-strange content. The results are compared with state-of-the-art phenomenological models implemented in commonly used Monte Carlo event generators, offering enhanced sensitivity to the underlying dynamics of strangeness production.
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Solar and Stellar Astrophysics
Solar Wind Dependence on Source Distance from the Open-Closed Boundary
Chloe P. Wilkins, David I. Pontin, Anthony R. Yeates et al. (+2 more)
The origin and variability of the slow
solar wind remains an open question in
solar physics, but is thought to be closely linked to dynamics at the Sun's open-closed
magnetic flux boundary (OCB). Interchange
magnetic reconnection at the OCB has been proposed as a mechanism for releasing closed-field
plasma into the heliosphere, but observational evidence linking
solar wind composition to OCB
topology remains limited. We relate in situ
solar wind measurements by Ulysses over a 10-year period to the
magnetic topology of their source regions using two coronal
magnetic field models: a potential field source surface model and a magnetofrictional model. We find a strong dependence of
solar wind composition on the distance of the source
magnetic flux from the OCB. Enhanced ion charge-state ratios, elemental abundances, and compositional variability are found to be concentrated within a supergranular-scale region (around 25 Mm) surrounding the OCB, consistent with the spatial scales of interchange
magnetic reconnection. This variability decreases systematically with increasing distance from the boundary, with coronal hole wind exhibiting more uniform fast-wind signatures. We also find that the composition of
solar wind emerging from regions close to the OCB is influenced by the strength of neighbouring closed
magnetic fields, with stronger fields preferentially associated with slow-wind properties. These results indicate that the composition of the slow wind is strongly governed by the
magnetic topology of the OCB, providing compelling evidence that interchange reconnection plays a crucial role in slow
solar wind release and structure.
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All authors Chloe P. Wilkins, David I. Pontin, Anthony R. Yeates, Nicholeen M. Viall, Spiro K. Antiochos
Nuclear Theory
Trace anomaly and interior curvature of neutron stars in energy-momentum squared gravity
Ratikanta Swain, Sayantan Ghosh and Bharat Kumar
In energy-momentum squared
gravity (EMSG), the spacetime inside a
neutron star is sourced by effective thermodynamic variables that need not coincide with the physical fluid pressure and energy density. It is therefore an open question whether the trace anomaly of dense matter – the QCD measure of how strongly conformal
symmetry is broken – still organizes interior profiles and
curvature in the same way it does in general relativity (GR). We adopt a clear matter-geometry separation: the trace anomaly is computed from the fluid sector alone, while spacetime
curvature scalars are built from the variables that actually source the modified Tolman-Oppenheimer-Volkoff equations. For five relativistic mean-field equations of state, the radial trace-anomaly profiles increase monotonically from core to surface in all accepted EMSG models, as in GR, but split systematically with the EMSG coupling strength; the splitting grows with
stellar compactness. Despite this deformation,
curvature invariants still fall onto organized bands when plotted against the trace anomaly, extending the GR thermodynamic-
geometric correspondence. The
Ricci contraction shows the tightest organization, whereas the
Ricci scalar remains the most equation-of-state sensitive. EMSG effects are modest for observationally accessible
stars but largest in stiff, ultracompact configurations, indicating that the trace anomaly remains a useful thermodynamic label for interior geometry even when
gravity couples nonlinearly to matter.
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High Energy Astrophysical Phenomena
Dependences of radio pulsar parameters on the kick velocity
Anton D. Lazarev and Sergei B. Popov
According to several studies, analysis of observational data and theoretical modeling favor a bimodal distribution of the natal velocity kick of
neutron stars. We analyze this proposal by using available data on
radio pulsars. For $\sim200$ normal isolated
radio pulsars with well-measured
spin and kinematic parameters, we determine if they belong to the low- or high-velocity mode of such a distribution by applying the parametrization proposed by Igoshev (2020). Our results demonstrate that about $23\%$ belong to the low-velocity mode. We then analyze the differences in the properties of the two sets of
pulsars belonging to the two modes. For some parameters (characteristic ages and distances), we see a clear difference between the two modes. However, for these quantities, it can be attributed to selection bias. For those parameters that are not subject to strong selection, such as pulse width, we do not observe any difference. Interestingly, we detect a notable difference in the
magnetic field distribution between the two modes. Lower-field
pulsars ($B\lesssim 10^{12}$~G) are overabundant among objects from the low-velocity mode. Among
pulsars with low fields ($\lesssim 10^{11}$~G), we do not identify any objects from the high-velocity mode of the kick distribution. The origin of this discrepancy is not clear, and we discuss several possibilities. Our analysis demonstrates that, most probably, this feature can be explained by selection effects. Thus, we conclude that there is no robust bimodality in physical parameters of
radio pulsars that can be related to the proposed bimodality of the kick velocity. This can be considered as an indirect argument against the hypothetical bimodality in the NS kick distribution. (abridged)
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Astrophysics of Galaxies
Abundances of CNO in candidate young metal-poor stars
Piercarlo Bonifacio, Elisabetta Caffau, Luca Sbordone et al. (+6 more)
In this contribution we investigate the CNO abundances in five apparently young evolved
stars, with the aim of discriminating between truly young
stars and
stars that were rejuvenated by accreting mass from another
star.
Stars that have accreted mass are expected to show low C and O and a very low [C/O] ratio, as displayed by some
stars in the Globular Cluster 47 Tuc, that are believed to have undergone mass-transfer. In our sample the low [C/O] ratios observed appear to be compatible with their evolutionary status. There is thus no indication for these
stars having accreted mass.__
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All authors Piercarlo Bonifacio, Elisabetta Caffau, Luca Sbordone, Lorenzo Monaco, Linda Lombardo, Rosine Lallement, Monique Spite, Patrick Francois, Alessio Mucciarelli
Instrumentation and Methods for Astrophysics
MOSAIC at ELT: Design and First Prototyping of Novel Robotic Optical-Relay Positioners
Maxime Rombach, Markus Thurneysen, Lucas Ortolani et al. (+27 more)
The Extremely Large
Telescope (ELT) is, to date, the most ambitious ground-based
telescope under construction. MOSAIC is a multi-objects spectrograph (MOS) that aims to make full use of the largest
telescope in the world. At its heart, about 300 robotic positioners will pick-off skylight from the focal surface of the ELT to feed it to its Near Infrared (NIR) and visible (VIS) spectrographs. The gigantic scale of the ELT presents three main challenges for MOSAIC positioners: (1) the light beams on the focal surface cannot be focused in a single fiber, similarly to other MOS instruments, involving a design with relay mirrors patrolling the field of view, and reimaging the sub-field on 2 fixed fiber bundles located 600 mm behind the ELT focal plane (2) The positioner needs to adapt to the local telecentricity, which means it has to point at the ELT pupil center located 37.868 m away from the focal plane (3) The Atmospheric Dispersion Corrector (ADC) needed to cover the whole focal surface of the ELT is impossible to build to this scale; hence each positioner needs its own ADC. EPFL is responsible for designing and supervising the mass manufacturing of the positioners. This paper aims to present its initial design and prototypes.
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All authors Maxime Rombach, Markus Thurneysen, Lucas Ortolani, Jurgen Schmoll, Diane Chapuis, Malak Galal, Sebastien Pernecker, Alec York, Ellen Schallig, Ian Lewis, Louis Gabarra, Cassio Berni, Ojonugwa Adukwu, Gavin Dalton, Fabio Fialho, Michaela Hirschmann, Thomas Augustejin, Kacem El Hadi, Marisa Garcia-Vargas, Marie Larrieu, Alessandro Meoli, Tim Morris, Roser Pello, Mathieu Puech, Myriam Rodrigues, Ruben Sanchez-Janssen, Alondra Sola, Jay Stephan, Christian Surace, Jean-Paul Kneib
Quantum Physics
Optimal multi-spectral squeezing via deterministic 2D-phase optimization
Bastien Oriot, Peter Namdar, Emilie Gillet et al. (+2 more)
Optimization routines are ubiquitous in
quantum information technologies and essential to reach the resource levels required by
quantum protocols. Specifically, multi-spectral squeezing for use in such protocols requires that losses be kept minimal at every stage, including coherent detection, which is performed by interfering the signal with a classical local-oscillator beam. This in turn requires control over all optical degrees of freedom of the beam in order to optimize the detection. The most general framework for this optimization relies on agnostic, off-the-shelf machine-learning techniques. Here we take the opposite approach: by focusing on a physical description of the specific optical process, we develop a deterministic sequential
algorithm that provably reaches the global maximum of the visibility in a pixel basis and scales linearly with the number of pixels, thereby offering an efficient and theoretically grounded alternative to black-box optimization. In our waveguide-based setup, the optimized mask increases the visibility from 76% to 84%, corresponding to a 20% gain in mode-matching efficiency. Multi-spectral squeezing measurements confirm that this improvement translates directly into
quantum readout: for the most squeezed spectral mode, the squeezing increases from $-2.08$ dB to $-2.64$ dB, consistent with the inferred efficiency gain. These results establish deterministic spatial phase shaping as an effective, interpretable route to enhanced multimode squeezing in waveguide platforms.
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All authors Bastien Oriot, Peter Namdar, Emilie Gillet, RL Rincon Celis, Valentina Parigi
Soft Condensed Matter
Independent Control of Transport and Order in a Ratcheted Colloidal Suspension
Sudipta Mandal, Dipanjan Chakraborty and Debasish Chaudhuri
We study directed transport in a two-dimensional suspension of repulsively interacting colloids driven by a
stochastic asymmetric piecewise-linear flashing ratchet using large-scale molecular dynamics simulations. The driving frequency and the ratchet asymmetry offer two independent ways of controlling the particle current, but they affect the suspension differently. At fixed asymmetry, the current shows a resonance with ratcheting frequency that is set by the collective relaxation dynamics of the interacting particles. The resulting increase in transport is accompanied by defect-mediated structural changes, showing density-dependent hexatic and solid-like states, with larger currents generally associated with weaker ordering. By contrast, at fixed frequency, changing the ratchet asymmetry mainly alters the strength of the directed bias and can significantly enhance the current while leaving the hexatic order largely unchanged. Near the
equilibrium hexatic-melting regime, this makes it possible to generate substantial directed currents without strongly disrupting sixfold orientational order. These results show that frequency tuning couples transport to structural reorganization, whereas asymmetry tuning primarily controls transport leaving the structure largely unaltered, providing distinct and complementary routes for manipulating transport and order in driven colloidal suspensions.
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Disordered Systems and Neural Networks
Truncated Wigner dynamics of biclique quantum spin glasses
Dries Sels
Quantum spin glasses are often considered testbeds for studying
quantum optimization
algorithms and as such have been the subject of various
quantum advantage claims. Here we investigate the near adiabatic dynamics of biclique
quantum spin glasses within the (discrete) truncated Wigner approximation (TWA).
Benchmarks on small systems show that TWA recovers sample-to-sample fluctuations of the Edwards-Anderson order parameter, over a wide range of annealing times, with increasing fidelity when the system size increases. We extract critical exponents from the Binder cumulant in line with theoretical expectations, reproducing recent
quantum experiments. The computational cost of the method is minimal and it can easily be applied to tens of thousands of
qubits.
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Quantum Physics
Operator learning for efficient quantum computation
Paul Over, Sergio Bengoechea, Leonardo Borello Busilacchi et al. (+3 more)
An efficient implementation of
quantum algorithms is often hindered by the lack of efficient primitives for operators and state preparation. This limits both the ability of near-term
quantum hardware to simulate complex problems and the potential of fault-tolerant
algorithms to achieve practical
quantum advantage. To address this, we propose a framework that maps discrete operators onto compact, structured
quantum circuits. The resulting variational
circuits can be tailored to the connectivity and long-range interaction of the target hardware. The learning process employs backpropagation together with a cost function that efficiently optimizes
unitary operators and non-
unitary –dense or sparse– operators using only a single ancilla
qubit for block encoding. Additionally, we introduce a regularization term that reduces the approximation error. The approach is validated for both
quantum mechanical and engineering applications. In the former case, we learn propagators that arise in native
quantum problems –such as
quantum simulation and
quantum chemistry– and achieve improved resource scaling in comparison to standard Suzuki–Trotter expansions. In the latter case, we demonstrate the approach's ability to implement the second-order central finite difference approximation of the Laplace operator –relevant for solving partial differential equations– while improving upon current error metrics. The final example deals with learning a dense, non-
unitary operator that arises in the analysis of inviscid potential flow around an airfoil. These results motivate the extension of the framework to a broader class of operator-synthesis problems beyond the prototypical engineering and
quantum applications considered here.
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All authors Paul Over, Sergio Bengoechea, Leonardo Borello Busilacchi, Martin Kiffner, Thomas Rung, Alexios A. Michailidis
Strongly Correlated Electrons
Anomalous Transverse Response in Nodal line Semimetal Mn$_{3}$SnC
Sunil Gangwar and C. S. Yadav
The interplay of topological surface states and magnetism gives rise to unconventional transport behaviors such as the anomalous
Hall effect (AHE) and anomalous Nernst effect (ANE). Antiperovskites such as Mn$3$SnC, which are nodal-line semimetals and exhibit concurrent
antiferromagnetic (AFM) and
ferromagnetic (FM) ordering, provide a fertile ground for anomalous transport phenomena. Here, we report that the anomalous transport (AHE and ANE) in this compound is predominantly governed by the intrinsic Berry-
curvature effect. We establish a unified relationship between the AHE and ANE using Mott's relation. Electron scattering by both AFM and FM
magnons is manifested in the anomalous Nernst signal. The ratio of the anomalous Nernst conductivity to the anomalous
Hall conductivity, $|\alpha^A{xy}|/\sigma^A_{xy}$, constitutes a sizable fraction of $k_B/e$, indicating a strong Berry-
curvature contribution to the ANE.
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Instrumentation and Detectors
Zhizheng Zhao, Changhao Qin, Rongfeng Zhang et al. (+5 more)
Cosmic-ray
muon scattering
tomography can image dense, shielded, or inaccessible objects without an artificial radiation source. In a compact magnet-free tracker, however, each accepted
muon provides only a few hit positions and no event-by-event momentum measurement. The downstream hit residual is therefore a compound observable: target scattering,
muon momentum, detector resolution, support material, air scattering, and track extrapolation all enter the same measured displacement. We introduce Nuisance-Aware
Muon Tomography (NAMT), a residual-likelihood reconstruction method for magnet-free trackers. The upstream hits define the incident track, downstream hit residuals carry the scattering signal, and a radiation-length density field $\lambda=1/X_0$ predicts their material-induced variance through a path integral. NAMT marginalizes the unmeasured momentum with a shared event-level scattering scale and uses open-field blank scans to fix detector and environmental residuals before object reconstruction. On eight Geant4
benchmark scenes spanning strong, weak, and negative scattering contrast, NAMT-4P reaches a mean area under the ROC curve (AUC) of $0.916$ at $120$k effective
muons and $1$ mm hit error, compared with $0.784$ for ASR, $0.749$ for MLS-EM, and $0.643$ for PoCA. NAMT-3P uses one downstream hit plane in reconstruction and still reaches $0.909$ mean AUC at the reference setting, while giving the highest reference mean contrast-to-noise ratio (CNR) and the best mean AUC at $30$k
muons.
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All authors Zhizheng Zhao, Changhao Qin, Rongfeng Zhang, Zibo Qin, Ziyu Xu, Xingyu Xiao, Qiang Li, Qite Li
Materials Science
Large spin splitting at ferromagnetic surfaces of bulk antiferromagnets
William A. Schaarman and Sophie F. Weber
We use density functional theory and model
Hamiltonians to reveal large
spin splitting of bands localized at
ferromagnetic surfaces of bulk antiferromagnets (AFMs). There is great interest in material platforms combining the robustness and ultrafast dynamics of AFMs with large, functional
spin splitting which is often restricted to ferromagnets (FMs). Here, we show that a subset of AFM surfaces which have
symmetry-allowed magnetization can host large
spin splitting via bulk degeneracy lifting of sublattice-resolved exchange splittings. We find that the
spin splitting is maximized for two
ferromagnetic surface motifs: terminations with single uncompensated
magnetic sublattices, and two-sublattice surfaces whose sublattices are magnetically compensated in the bulk, but acquire distinct
crystal field environments via surface truncation. The latter case can yield FM-like
spin splitting magnitudes while also having small uncompensated magnetization. We confirm these predictions with first-principles calculations of $\mathrm{Cr_2O_3}$ and $\mathrm{FeF_2}$, finding splittings as large as $1~\mathrm{eV}$ depending on the surface in question. Our findings point to intrinsic surface
symmetry breaking as a route to large, functional
spin splitting in an expanded range of AFM materials.
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Quantum Physics
Quantum-Accelerated Self-Consistent Field: A Hybrid Algorithm
Alexis Ralli, Tim Weaving, Thomas M. Bickley et al. (+2 more)
We present the Grover adaptive search self-consistent field (GAS-SCF)
algorithm. GAS-SCF leverages
quantum arithmetic to construct an efficient oracle that marks target states (Fock states) which improve upon some initial classical energy estimate. Amplitude amplification then increases the probability of measuring these states. This approach offers a theoretical quadratic speed-up for the optimization problem encountered in SCF
quantum chemistry and establishes a baseline against which structured optimization
algorithms, such as QAOA and DQI may be compared. In this work, we classically simulate three examples as proofs of concept of the
algorithm, the largest consisting of 26
qubits. We then extend our analysis to two larger systems, with O3 representing the largest case at 330
qubits. These examples are chosen to probe classically challenging SCF regimes. Achieving chemically relevant applications of GAS-SCF will require large-scale, fault-tolerant
quantum hardware.
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All authors Alexis Ralli, Tim Weaving, Thomas M. Bickley, Peter V. Coveney, Peter J. Love
Astrophysics of Galaxies
A Consistent Comparison of Intracluster Light Assembly in Simulations I. Redshift Evolution and Progenitor Galaxies
Harley J. Brown, Garreth Martin, Frazer R. Pearce et al. (+5 more)
The
tidal stripping of satellite
galaxies and the
stellar detritus ejected during
galaxy mergers builds up a diffuse
stellar component in
galaxy clusters known as the intracluster light (ICL). We investigate ICL assembly in cluster-mass
haloes ($M_{178c}\sim10^{14}-10^{15}$ M$_\odot$) using four different hydrodynamical simulations (Horizon-AGN, TNG100, The Three Hundred Gizmo-Simba 7K, and Hydrangea) under a homogenized ICL identification framework. For our fiducial ICL definition we obtain broadly consistent $z\approx0$ ICL
stellar mass fractions ($\sim0.1-0.2$) and, by tracking the progenitors of $z\approx0$ clusters back to $z\gtrsim2$, find no significant
evolution in average ICL mass fractions. Alternative approaches for distinguishing the ICL from the central
galaxy show the absolute ICL fraction to be highly sensitive to adopted definition, but we never find any significant inter-simulation discrepancies when implementing a consistent methodology to identify the ICL. Whether the average ICL mass fraction falls with increasing
redshift or does not evolve is determined by the ICL definition adopted. By tracing $z\approx0$ ICL
stars back to their progenitor
galaxies, we find that lower-mass satellites typically make slightly larger ICL contributions relative to their mass in every considered simulation, but which
galaxies make the dominant contribution to the ICL is primarily controlled by the infalling satellite mass function. Most ICL
stars sourced from satellite
galaxies are therefore expected to originate from
galaxies with infall
stellar masses above $\sim10^{10}$ M$_\odot$ and largely within $10^{10.5}-10^{11.5}$ M$_\odot$.
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All authors Harley J. Brown, Garreth Martin, Frazer R. Pearce, Yannick M. Bahé, Madeline Butler, Weiguang Cui, Nina A. Hatch, Alexander Knebe
Cosmology and Nongalactic Astrophysics
High-accuracy polarimetry for CMB: new frontiers with the POLOCALC project
A. Novelli, F. Astori, L. Bizzarri et al. (+8 more)
Modern
telescopes observing the
Cosmic Microwave Background (CMB) polarization require an exquisite control of systematics to target Inflationary Gravitational Waves (IGW),
Cosmic Birefringence (CB), and
Primordial Magnetic Fields (PMF). The absolute polarization angle of the detectors is a critical parameter to disentangle the $E$-modes and $B$-modes of the CMB, allowing a correct detection of
primordial $B$-modes as well as testing
Cosmic Birefringence theories. To this end, we discuss the current status of the POLOCALC project, an ERC Advanced Grant that aims to develop air-borne calibration sources for CMB small-aperture
telescopes. The main scientific objective of POLOCALC is to enable a direct calibration of the absolute polarization angle of CMB polarimeters with an accuracy of $0.01 \degree $. We present the latest developments regarding the calibration source, the calibration strategies designed to use drone-based calibrators, and the application to modern ground-based experiments.
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All authors A. Novelli, F. Astori, L. Bizzarri, F. Cacciotti, G. Cattaneo, G. Coppi, N. Dachlythra, I. Karaaslan, N. Mezzanzanica, F. Nati, M. Zannoni
Mesoscale and Nanoscale Physics
Transient triplet blockade in Andreev junction
R. Taranko, J. Baranski, A. Jankiewicz et al. (+3 more)
We study the time-dependent triplet configuration, appearing under nonequilibrium conditions in a nanoscopic junction with two
quantum dots coupled in series between
superconductor and normal metallic lead. We show that in the situation, when both
quantum dots are singly occupied by identical
spin electrons, the on-dot electron pairing is suppressed what substantially affects the subgap charge transport. We investigate processes in which such configuration can be temporarily encountered, either due to the initial conditions or by imposing the external
magnetic field. Our analytical and numerical calculations provide estimations for the temporal scales, characterizing
evolution of the triplet configuration which could be manifested in the time-resolved tunneling measurements. Such nonequilibrium features of the triplet configuration might be relevant to operations on superconducting
qubits, in their conventional and/or topological realizations.
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All authors R. Taranko, J. Baranski, A. Jankiewicz, K. Wrzesniewski, I. Weymann, T. Domanski
Statistical Mechanics
Norms, overlaps and Yangian descendants for the Haldane-Shastry spin chain
Yunfeng Jiang, Jules Lamers and Yuan Miao
The Haldane-Shastry
spin chain is a prototypical integrable model with long-range interactions, notable for hosting quasiparticles with fractional statistics and serving as a discrete analogue of a conformal field theory. Its remarkable simplicity is closely tied to a full Yangian
spin symmetry. While the highest-weight states for this
symmetry are known explicitly, a systematic treatment of the descendant states, needed for the computation of various physical quantities, has remained incomplete. In this work, we provide a detailed construction of these descendants in terms of the algebraic Bethe ansatz following recent work of Ferrando et al. In the limit of extreme twist, it includes the Gelfand-Tsetlin basis. As an application, we derive product and determinant formulae for norms and overlaps of these states.
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