Mathematical Physics
Existence and absence of Bose-Einstein condensation in the interacting random Kac-Luttinger model
C. Boccato, J. Kerner, M. Pechmann et al. (+1 more)
In this paper, we study interacting
bosons at zero temperature in a random and higher-dimensional continuum model introduced by Kac and Luttinger. For weak interactions we prove that there is condensation in the lowest eigenstate of the one-particle
Hamiltonian (type-I BEC). For strong interactions, however, we show that condensation in a localized state cannot occur. We also prove generalized condensation, where a family of eigenstates of the one-particle
Hamiltonian is macroscopically occupied as a whole. Combining these results yields a scenario where there is generalized condensation into a family of eigenstates of the one-particle
Hamiltonian, but none of them is macroscopically occupied itself (type-III BEC). This proves a transition in the type of condensation. To the best of our knowledge, this is the first rigorous result in this direction for a random continuum model in higher dimensions.
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All authors C. Boccato, J. Kerner, M. Pechmann, W. Spitzer
Quantum Physics
Action on the Sphere: An Interfering Mean-Field Propagator for the Bose-Hubbard Dimer
Elana F Todd-Miller and Eva-Maria Graefe
The Bose-Hubbard system has been studied extensively both theoretically and experimentally, in particular in the context of ultracold atomic gases in optical
lattices. Even in the two-mode case the many-particle dynamics display complex interference effects resulting in revival and breakdown phenomena as well as tunnelling. The most basic theoretical description is the mean-field approximation, which can be derived from a time-dependent variational principle assuming the many-particle wave function is an SU(2) coherent state. Here we build on this to construct a simple initial-value coherent state propagator, summing over mean-field trajectories and keeping track of their phases, given by the corresponding mean-field actions. This yields an approximation to the full time-dependent many-particle state, and is able to reproduce breakdown and revival dynamics. Applying a time-slicing procedure on top of this, we are able to accurately capture many-particle tunnelling effects. While in this paper we focus our analysis on the Bose-Hubbard dimer, the methods developed can be applied to more general SU(2)
Hamiltonians, and can be extended to SU(M) systems.
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General Relativity and Quantum Cosmology · Cross-listed from math.DG
Differential Invariants of Carrollian Spacetimes
Boris Kruglikov, Eivind Schneider and Wijnand Steneker
We compute invariants of Carrollian spacetimes, deriving them from the geometry of the screen bundle. For generic Carrollian structures we specify how to generate the entire
algebra of differential invariants, with emphasis on dimension 3, which has special physical relevance. Then, in the framework of jet-spaces, we compute the numerology behind these invariants: the
Hilbert and Poincaré functions that govern their numbers according to order. Finally, we compute the Spencer
cohomology behind the Carrollian geometry that, in particular, contains the spaces of intrinsic torsion and intrinsic
curvature, which are fundamental invariants, important in the equivalence problem and
symmetry analysis. Thus, we also discuss
symmetry sizes of Carrollian spacetimes.
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Fluid Dynamics
Sudden expansion stability thresholds modified by lateral flows
T. Salamon, R. Debuysschère, A. Chafaï et al. (+2 more)
We study the flow in a symmetric three-dimensional confined sudden expansion with lateral inflow at Reynolds number below 300 and varying lateral-to-central flow rate ratio, using experiments, linear stability analysis, weakly nonlinear theory, and direct numerical simulations. Three distinct flow regimes are identified. Outside an intermediate band of lateral-to-central flow rate ratio, the flow undergoes a steady
symmetry-breaking bifurcation above a critical Reynolds number, deflecting the central jet toward one side wall; weakly nonlinear analysis shows this bifurcation to be supercritical, excepting a very narrow parametric range. Within the intermediate band, no such critical Reynolds number exists and direct numerical simulations confirm that residual velocity asymmetries reflect the imposed
geometric imperfections rather than intrinsic amplification. Fluctuations observed experimentally in the intermediate band of lateral-to-central flow rate ratio remain unexplained and warrant further investigation.
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All authors T. Salamon, R. Debuysschère, A. Chafaï, B. Scheid, F. Gallaire
Soft Condensed Matter · Cross-listed from q-bio.SC
Pathway variability, coat stiffening and mechanical adaptation during clathrin-mediated endocytosis
Johannes H. H. Dreckhoff, Ulrich S. Schwarz and Leon Lettermann
Clathrin assemblies in
cells can persist as flat plaques, abort after partial invagination, or close into clathrin-coated vesicles, but the determinants of these different fates remain unresolved. To investigate the
stochastic and complex dynamics of clathrin assemblies, we have developed a kinetic Monte Carlo simulation framework that couples individual clathrin
agents to an adaptive continuum membrane. In this hybrid discrete-continuum description, the effective coat bending
rigidity and the preferred coat
curvature emerge during growth, rather than being prescribed as material parameters. Once connected, curved
lattices stiffen from molecular bending modes to coat-level
rigidities, because
curvature changes require increased stretching or compression, while newly incorporated triskelia hardcode a history-dependent preferred
curvature. An analytical theory for non-Euclidean elasticity identifies the relevant internal variables and predicts growth laws that are validated by the simulations. The same microscopic assembly rules yield flat, stalled, and closed coats through two sequential gates in the effective membrane-coat energy landscape. Comparisons with experimentally observed coat geometries and nanodissection-induced
curvature changes agree with our theoretical predictions without any fitting parameters. The clathrin coat thus emerges as an adaptive assembly with prestress and
memory, whose fate and material parameters reflect the environment in which it has been growing.
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High Energy Astrophysical Phenomena
Systematic study of the morphology and length of slow stable hybrid star branches
Mauro Mariani, Milva G. Orsaria, Germán Lugones et al. (+1 more)
We introduce and systematically study the length of the slow stable hybrid
star branch as a quantitative measure of the extended stability region that arises in hybrid
neutron stars when the
hadron-
quark phase conversion is slow compared to the radial oscillation timescale. Combining generalized piecewise-polytropic hadronic equations of state of varying stiffness with a constant-speed-of-sound
quark-matter model, we construct a large set of hybrid equations of state spanning a broad range of transition pressures, energy-density jumps, and
quark-matter speeds of sound. We identify four morphological types for the slow stable branch in the mass-radius plane: waterfall branches that descend monotonically from the hadronic maximum mass, bridges that connect the hadronic branch to a second unconditionally stable hybrid branch, tails that extend briefly beyond the maximum mass of an unconditionally stable hybrid branch, and tail-bridges that combine features of the latter two. Their prevalence is governed primarily by the transition pressure and the energy-density jump, while the branch length is also significantly influenced by the stiffness of the hadronic sector and the
quark-matter speed of sound. Imposing current astrophysical and microphysical constraints shows that viable long branches are predominantly of waterfall type, and that stiff hadronic equations of state – strongly disfavored under the rapid-conversion assumption – remain compatible with all current constraints within the slow-conversion framework. In the plane of transition
baryon density versus density jump, slow stable configurations open a new region of viable parameter space inaccessible under rapid conversions.
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All authors Mauro Mariani, Milva G. Orsaria, Germán Lugones, Ignacio F. Ranea-Sandoval
Statistical Mechanics
Robust secret storage in networks
Vinko Zlatić
The problem of storing secure information on a network is studied. A formal framework for distributed secret storage is introduced, and possible applications in technological and social systems are discussed. The problem is formulated as the optimization of a robustness functional in which two competing requirements are balanced: survivability under network-degrading processes and resistance to
adversarial compromise. An exact representation of survivability is derived in terms of minimal information-carrying subgraphs (MICS), which provide a reduced description of the reconstruction events relevant to the stored information. This representation is then used to construct semi-local optimization methods whose dynamics do not require global knowledge of the network structure. Finally, it is shown that, in a limiting case, the robustness functional can be mapped naturally to an effective
spin Hamiltonian.
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Quantum Physics
Photonic Violation of Wigner's Inequality
Maximilian Rottensteiner, Dorian Schiffer, Tobias Pausch et al. (+2 more)
Teaching
quantum mechanics is challenging, not least because the theory often conflicts with our classical worldview.
Quantum correlations in particular are notoriously counter-intuitive. Their non-classical behavior is typically revealed through Bell-type inequalities. Among these, Wigner's Inequality constitutes a particularly accessible test, as it relies on minimal set-theoretic assumptions. In this pedagogical paper, we derive Wigner's Inequality, describe a
quantum-optical setup to experimentally violate it, and provide access to the raw data, enabling students and instructors to perform their own analyses. Our measured data shows clear violations of Wigner's Inequality, directly illustrating the non-classical nature of
quantum correlations. By connecting theory, experiment, and data analysis, this paper equips educators with a resource for engaging students in authentic scientific practice and developing a deeper understanding of
quantum systems.
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All authors Maximilian Rottensteiner, Dorian Schiffer, Tobias Pausch, Alois Mair, Anton Zeilinger
Astrophysics of Galaxies
No evolution in the number density of little red dots from cosmic dawn to cosmic noon
Federica Loiacono, Roberto Gilli, Marco Mignoli et al. (+24 more)
We present our search for little red dots (LRDs) in the "J1030 field", a region of the sky around the $z\sim 6.3$
quasar SDSS J1030+0524, observed by the JWST EIGER program. Over 154 point-like sources selected in a JWST-based photometric catalog, we find five broad line emitters (with $FWHM \gtrsim 1000\ \rm km s^{-1}$) that are red ($F200W - F356W > 0$) and are undetected in the X-rays. We use these sources to derive the bolometric luminosity function (LF) of LRDs at $z = 2.4$ and $z = 4.5$. At $z = 2.4$, the space density of LRDs is only a factor of $\sim 2$ lower than that of all pre-JWST active
galactic nuclei (AGNs) with bolometric luminosity $L_{\rm bol} \gtrsim 3 \times 10^{44}\ \rm erg\ s^{-1}$. At $z = 4.5$, our estimate is consistent with those derived for LRDs based on larger areas of the sky. A similar behaviour is observed in the black hole mass function. More importantly, we study the number density of LRDs from
cosmic dawn to
cosmic noon. We find that there is no significant
evolution in the abundance of LRDs with $L_{\rm bol} \gtrsim 3 \times 10^{44}\ \rm erg\ s^{-1}$ at $z > 2$. We speculate that the drop at $z < 4$ seen by other studies is due to their sampling of only the bright-end of the LRDs LF. At
cosmic noon, the abundance of LRDs is $n = 3.4^{+5.6}_{-2.4} \times 10^{-5}\ \rm Mpc^{-3}$, which is a factor of $\sim 350$ larger than recent model predictions and is comparable with that of X-ray selected AGNs with similar bolometric luminosity. Our result may imply that, if LRDs are the early, rapid stages of supermassive black hole growth, as suggested by some models, then the formation of black hole seeds can be efficient down to epochs as recent as
cosmic noon. Alternatively, LRDs may simply be a high-
accretion phase in already mature black holes.
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All authors Federica Loiacono, Roberto Gilli, Marco Mignoli, Marcella Brusa, Francesco Calura, Marco Chiaberge, Andrea Comastri, Quirino D'Amato, Roberto Decarli, Ivan Delvecchio, Kazushi Iwasawa, Ignas Juodžbalis, Giorgio Lanzuisi, Roberto Maiolino, Stefano Marchesi, Giovanni Mazzolari, Colin Norman, Alessandro Peca, Isabella Prandoni, Matteo Sapori, Matilde Signorini, Paolo Tozzi, Eros Vanzella, Cristian Vignali, Fabio Vito, Gianni Zamorani, Anita Zanella
Mesoscale and Nanoscale Physics
Topological control of third-harmonic generation in a mesoscopic quantum ring with spiral dislocation
Carlos Magno O. Pereira, Denise Assafrão and Edilberto O. Silva
We investigate the nonlinear optical response of a two-dimensional mesoscopic
quantum ring subjected to a spiral dislocation, with emphasis on third-harmonic generation (THG). The topological defect is modeled through a torsion-induced deformation of space, which modifies the effective metric without introducing
curvature. By combining the minimal-coupling prescription in curved space with a radial ring confinement and a perpendicular
magnetic field, we derive the effective radial Schrödinger problem, obtain the bound states, and evaluate the nonlinear susceptibilities within the electric-dipole approximation. We show that the axial
symmetry of the topologically deformed ring preserves the dipole selection rule $\Delta m=\pm 1$ and therefore suppresses second-harmonic generation, while THG remains allowed through multistep transition chains. The study is further expanded through three complementary analyses that can be implemented without changing the
Hamiltonian: a dephasing-controlled study of spectral resolution, three-dimensional waterfall spectra showing the dependence on $\beta$ and $B$, and a channel-resolved decomposition of the THG amplitude. Together, these results establish the spiral dislocation as a robust
geometric knob for tuning nonlinear optical activity in mesoscopic ring-shaped nanostructures.
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Quantum Physics
Quantum percolation based dynamic propagation connectivity for critical-area identification in transport networks
Junxiang Xu, Chence Niu, Vinayak Dixit et al. (+2 more)
Transport networks often lose functionality through gradual degradation in link operating conditions before topological disconnection occurs. Link-centred and binary percolation measures identify important facilities or connectivity failures, but they provide limited information on which spatial areas cause the largest loss of network-wide propagation capability. This paper develops a Dynamic Propagation Connectivity (DPC) metric based on
quantum percolation for critical-area identification in transport networks. Time-varying link travel times are converted into continuous propagation strengths, which define a Hermitian propagation operator at each observation time. Candidate regions are then evaluated by a regional degradation experiment that measures the resulting loss of DPC. The method is applied to a
benchmark Sioux Falls network and six Florida road networks during the post-Hurricane Irma disruption and recovery period, using 1,281 five-minute observation times. The
benchmark confirms that the regional DPC score identifies a predefined structurally critical corridor. In the Florida networks, the identified critical areas differ from regions selected by link count, local degradation, edge betweenness, algebraic connectivity, and classical percolation. In Networks 1 to 4, DPC and classical percolation rankings have negative Spearman correlations, showing that continuous propagation degradation and binary fragmentation reveal different vulnerability patterns. Robustness tests under alternative travel time scaling, degradation strength, and grid size show stable results, with mean rank agreement between 0.84 and 0.96. The findings extend transport resilience analysis based on percolation from binary connectivity loss to continuous propagation degradation and provide a spatial diagnostic tool for regional monitoring, emergency planning, and recovery prioritisation.
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All authors Junxiang Xu, Chence Niu, Vinayak Dixit, Divya Jayakumar Nair, Tingting Zhang
Statistical Mechanics
Surviving the Attack of the Clones
Denis S. Grebenkov
We consider a population dynamics model in which each diffusing particle that hits a catalytic surface can split into two independent copies (clones). The particles of such a growing-in-size population search in parallel for a hidden partially reactive target to trigger a reaction event (e.g., a viral attack). We investigate the statistics of the fastest first-reaction time (FRT) among all the particles. We establish a nonlinear integral equation for the survival probability and then analyze the associated probability density of the FRT and its moments. Lower and upper bounds on the mean FRT are then deduced in terms of the system parameters (target reactivity, catalytic rate, diffusivity, etc.). Because autocatalytic replication can rapidly increase the number of searchers, it can substantially accelerate the diffusive search. We solve the nonlinear equations numerically in a basic
geometric setting and reveal advantages and limitations on the autocatalytic search.
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Materials Science
Boron-assisted stabilization of low-resistivity mixed-valence Cu-O thin films prepared by reactive magnetron sputtering
Nirmal Kumar, Jemal Yimer Damte, Michal Procházka et al. (+5 more)
This study systematically investigated the influence of boron incorporation in Cu-O thin films and the effect of oxygen partial pressure ($p_{\rm ox}$) on the phase
evolution, chemical bonding, and electrical characteristics of the prepared films. A phase transition from Cu$_2$O to Cu$_2$O/Cu$_4$O$_3$ to CuO was observed as oxygen partial pressure increased. Boron incorporation significantly broadened the stability window of the Cu$_2$O and Cu$_4$O$_3$ phases and delayed the transition to CuO at higher oxygen partial pressure. In the highly B-doped Cu-O films, Cu$_4$O$_3$ was stabilized even under oxygen-rich conditions along with the CuO phase, suggesting that boron significantly altered the oxidation pathway. The formation of B-O and possible B-O-Cu configurations altered the local oxygen chemistry and promoted mixed-valence copper
oxide phases. Electrical measurements revealed that highly B-doped Cu-O films exhibited a delayed transition from a high-resistivity low-$p_{\rm ox}$ regime to a low-resistivity mixed-valence regime, ultimately reaching approximately 0.06 $\Omega$ cm, among the lowest reported resistivities for a CuO-like material. These findings demonstrate that boron doping is an effective approach for tailoring the phase stability, defect chemistry, and electrical characteristics of Cu-O thin films for optoelectronic and photovoltaic applications.
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All authors Nirmal Kumar, Jemal Yimer Damte, Michal Procházka, Radomír Čerstvý, Jiří Houška, Pavel Baroch, Stanislav Haviar, Jiří Rezek
High Energy Physics (Theory)
Complex Phase Structure and Widom line for Euler Heisenberg black holes
Mozib Bin Awal and Prabwal Phukon
We investigate the supercritical thermodynamics of Euler-Heisenberg AdS black holes within the framework of Lee-Yang phase transition theory. We show that the system admits two distinct critical points associated with a four-phase thermodynamic structure and identify a degenerate higher-order critical point where the two criticalities merge. Extending the thermodynamic description into the complex domain, we determine the distribution of Lee-Yang singularities and construct the corresponding complex phase diagrams. At the degenerate critical point, we find that a well-defined Widom line emerges despite the absence of a conventional coexistence curve, acting as an effective stability boundary in the supercritical regime. In the two-critical-point regime, the complex phase diagram exhibits two distinct Widom lines, one associated with a coexistence curve and the other arising solely from the complex singularity structure. We further show that the Lee-Yang formalism consistently reproduces the expected phase structure for systems with a single critical point and in the absence of criticality. Our results reveal a rich supercritical phase structure and provide new insights into the origin and physical interpretation of Widom lines.
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High Energy Physics (Theory)
Exact calculation of entanglement negativity for a 1+1D massless scalar field using phase space methods
Jason Pye, Atharva Hingane and Robert H. Jonsson
Quantum fields exhibit a rich
entanglement structure which is still not fully understood. In this work, we study the
entanglement structure of the
vacuum state of a massless scalar field in (1+1)-dimensions – a paradigmatic case for both high energy and condensed matter physics. We fully characterize the
entanglement negativity between two arbitrary compact spacelike-separated regions of the field by calculating the logarithmic negativity along with the modes carrying it, called negativity cores. We achieve this using a framework based on the Kähler structure of Gaussian states, wherein we calculate the diagonalization of the operator associated with the partially-transposed restricted linear complex structure. In doing so, we extend the methods of this framework by proposing a basis-independent definition of the transpose operation. The explicit diagonalization we perform is enabled by a reformulation of the
eigenvalue problem as a boundary value problem in the complex plane. Our results also suggest extensions to higher dimensions and fermionic fields.
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Cosmology and Nongalactic Astrophysics
Cosmology with Multi-Wavelength Line Intensity Mapping Synergies in the SKAO Era
Debanjan Sarkar, Suman Majumdar, Chandra Shekhar Murmu et al. (+21 more)
Line intensity mapping (LIM) has emerged as a powerful tool for surveying the large-scale structure of the Universe across
cosmic time by measuring spatial fluctuations in the cumulative emission of spectral lines from unresolved sources or the intergalactic medium. Besides the most abundant 21-cm hyperfine line of neutral hydrogen, there are bright far-infrared fine-structure lines like [CII] 158 $\mu$m, [OIII] 88 $\mu$m, [NII] 122/205 $\mu$m, and [OI] 63 $\mu$m, as well as mid-/high-$J$ CO rotational transitions, hydrogen Ly$\alpha$ and H$\alpha$ as potential LIM probes. A key opportunity lies in combining and cross-correlating 21-cm intensity maps from SKAO with other line intensity maps, targeted by a range of ongoing and forthcoming LIM experiments that probe overlapping
cosmic volumes. Cross-correlation between 21-cm maps and other line tracers mitigates uncorrelated systematics and enhances sensitivity to the underlying matter distribution, while multi-line analyses help disentangle cosmological and astrophysical parameters. Beyond cross-power spectra, higher-order and morphological statistics – such as cross-bispectra, marked correlations, and morphological measures – capture non-Gaussian features and the environmental dependence of structure formation. This chapter explores the synergies that can be achieved by combining SKAO observations with other line-intensity mapping experiments, demonstrating how such joint analyses can unlock new insights into
galaxy evolution and cosmology.
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All authors Debanjan Sarkar, Suman Majumdar, Chandra Shekhar Murmu, Leon Noble, Manas Mohit Dosibhatla, Vishrut Pandya, José Luis Bernal, Yashrajsinh Mahida, Mohd Kamran, Caroline S. Heneka, Anshuman Tripathi, Samit Kumar Pal, Gabriella De Lucia, Fabio Fontanot, Matteo Viel, Marta Spinelli, Parth Kothari, Sarah Libanore, Abinash Kumar Shaw, Martin Sahlen, José Fonseca, Abhirup Datta, Ziad Sakr, Wenkai Hu
High Energy Physics (Phenomenology)
Multiparameter Quantum Estimation and Degeneracy Structure in Three-Flavor Neutrino Oscillations
Bhavna Yadav, Amir Subba and Yu Shi
We investigate three-
flavor neutrino oscillations within the framework of
quantum estimation theory using the
quantum Fisher information
matrix (QFIM). We analyze all six independent elements of the QFIM for the parameters $\theta_{23}$, $\delta_{\mathrm{CP}}$, and $\Delta m^2_{31}$, together with the corresponding
quantum Cramér–Rao bounds and normalized parameter correlations. To connect the intrinsic
quantum sensitivity of the
neutrino state with experimentally accessible information, we further compare the QFI with the classical Fisher information (CFI) associated with
flavor-probability measurements. We find that the difference between the
quantum and classical information bounds is strongly dependent on the oscillation parameter and $L/E$, demonstrating that the efficiency with which the available
quantum information is accessed depends on the measurement. We also investigate probability-degenerate solutions in the $(\theta_{23},\delta_{\mathrm{CP}})$ parameter space. Although different parameter sets can produce identical $\nu_\mu\rightarrow\nu_e$ appearance probabilities at specific $L/E$ values, their corresponding
quantum states can remain distinct, as demonstrated by the
quantum fidelity. The QFIM differences further reveal distinct local
quantum-information geometries for these probability-degenerate solutions, while the corresponding CFIM differences show a parameter and $L/E$ dependent degree of distinguishability accessible through the
flavor-probability measurement. Our results demonstrate that QFI and CFI provide complementary information for
neutrino parameter estimation, with the QFIM serving as a measurement-independent
quantum benchmark and the CFI characterizing the information accessible through a specified measurement.
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Chemical Physics
How is Water released in Hydrogen-Based Metal Oxide Reduction? Unraveling the Kinetic Bottleneck in Sustainable Metal Production
Zhaoxi Chen, Yulu He, Zhuoran Yao et al. (+11 more)
Hydrogen-based direct reduction of metal
oxides is a ubiquitous solid-gas redox process central to geophysics, sustainable metallurgy, redox energy cycles and catalysis. During this process, hydrogen removes
lattice oxygen to form water, yet product water has long been regarded as a passive exhaust, and its nanoscale formation, trapping and removal remain poorly understood. Here, we directly observe redox-product water release from iron
oxide during hydrogen-based direct reduction. Because water removal emerges from coupled structural, chemical and crystallographic
evolution across multiple length-scales under realistic non-
equilibrium reaction-conditions, we establish a correlative multiscale in-situ approach that links pore
evolution, molecular water signatures, phase transformation and chemical-state
evolution during hematite reduction. We uncover a mechanism in which oxygen removal induces closed nanopores spatially delocalized from reaction surfaces, causing transient trapping of water vapor. Water is released only when these pores coalesce into a percolating network connected to the surface, coinciding with and accelerating the onset of the hematite-to-magnetite transformation. These findings show that dynamically evolving pore
topology governs mass transport and redox kinetics in solid-gas reactions, closing a critical mechanistic gap in product-water removal and providing nanoscale guidance for hydrogen-based metal extraction, reactor design, and sustainable redox energy technologies under practical conditions.
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All authors Zhaoxi Chen, Yulu He, Zhuoran Yao, Chunwen Wang, Lei Lei, Jun Cai, Martin Aaskov Karlsen, Claudio Pistidda, Wu Zhou, Marc-Georg Willinger, Yan Ma, Dierk Raabe, Zhi Liu, Zhu-Jun Wang
Quantum Physics
Quantum percolation theory for dynamic propagation connectivity of transport networks
Junxiang Xu, Chence Niu, Divya Jayakumar Nair et al. (+1 more)
Connectivity degradation in transport networks under structural disturbance is a central problem in network resilience research. Existing methods rely mainly on percolation theory and topological connectivity measures. They focus on whether paths exist and whether connected components fragment. These approaches cannot capture functional degradation where network
topology remains intact but propagation ability has already declined substantially. This paper introduces
quantum percolation theory into transport network connectivity analysis and proposes Dynamic Propagation Connectivity (DPC) as a new measure that characterises network propagation ability under disturbance. By mapping a transport network under disturbance into a propagation operator system, this paper establishes a spectral analysis framework for DPC and defines the time-averaged participation index as its core quantification. This paper provides a series of rigorous theoretical results. DPC remains constant under homogeneous disturbance and degrades under heterogeneous disturbance. This paper establishes a quantitative relationship between the degradation rate, the minimum
eigenvalue spacing of the propagation operator, and heterogeneous deviation strength. This paper proves a separation
theorem between DPC and algebraic connectivity. It derives an analytical expression for DPC and a second-order perturbation approximation on the ring graph. Numerical experiments on three transport
benchmark networks verify all theoretical conclusions and confirm degradation monotonicity, separation from algebraic connectivity, and degradation amplification by network size. This paper provides a theoretical framework for transport network resilience assessment that goes beyond topological connectivity.
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All authors Junxiang Xu, Chence Niu, Divya Jayakumar Nair, Vinayak Dixit
Atomic Physics
All-Optical Control of Birefringence in a Cold Atomic Ensemble
Apoorva Apoorva, Naudson Lucas Lopes Matias, Bérengère Pinoche et al. (+3 more)
We demonstrate all-optical control of birefringence in a cold atomic cloud of ytterbium. By optically dressing the excited $^{3}\mathrm{P}_1$ state via an off-resonant coupling to the $^{3}\mathrm{D}_1$ level, we induce polarization-dependent light shifts of the Zeeman sublevels, resulting in a tunable polarization-dependent refractive index. For a circularly polarized dressing beam, we observe a rotation of the probe linear polarization, characteristic of the Faraday effect, in the absence of any
magnetic field. In addition, for a linearly polarized dressing beam, the probe acquires ellipticity without rotation, corresponding to linear birefringence. More generally, the polarization of the dressing beam controls the axis of rotation of the probe polarization on the Poincaré sphere. Our results establish cold atoms as a versatile platform for engineering and controlling light-induced birefringence and open new perspectives for the fast and reconfigurable control of optical response of resonant media.
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All authors Apoorva Apoorva, Naudson Lucas Lopes Matias, Bérengère Pinoche, Daniel Benedicto Orenes, Robin Kaiser, Raphaël Saint-Jalm
Mesoscale and Nanoscale Physics
Rolling Two-Dimensional Collinear Magnets into Chiral Nanotubes with $p$-Wave Magnetism
Zhejunyu Jin, Robin R. Neumann, Rodrigo Jaeschke-Ubiergo et al. (+2 more)
$p$-wave magnets are noncollinear compensated
magnetic systems that exhibit nonrelativistic antisymmetric
spin splitting in momentum space. Their odd-parity
spin symmetry enables unconventional spintronic functionalities, including highly efficient charge-to-
spin conversion via the Edelstein effect. An outstanding question is whether such
magnetic phases can emerge from simple and broadly accessible
magnetic building blocks rather than from intrinsically noncollinear
magnetic orders. Here, we show that rolling two-dimensional collinear magnets – ferromagnets, antiferromagnets, and altermagnets – into nanotubes generates a rich
spin-
symmetry landscape controlled by
curvature, chirality, and
magnetic order. Remarkably,
chiral nanotubes hosting radial or tangential coplanar
spin textures generically realize $p$-wave magnetism irrespective of the underlying collinear parent phase. The emergent odd-parity
spin symmetry manifests itself in both electronic and magnonic spectra through antisymmetric $p$-wave
spin splitting. Our results establish
magnetic nanotubes as a versatile platform for engineering unconventional $p$-wave magnetism and predict a nonrelativistic Edelstein response that exceeds conventional
spin-orbit-driven charge-to-
spin conversion by more than an order of magnitude.
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All authors Zhejunyu Jin, Robin R. Neumann, Rodrigo Jaeschke-Ubiergo, Jairo Sinova, Alexander Mook
High Energy Physics (Phenomenology)
Doubly charmed baryon-light meson scattering in chiral effective theory with lattice constraints
Peng-Qi Wang and Zhi-Hui Guo
We study the scattering of the ground states of doubly charmed
baryons ($\Xi_{cc}^{++},\Xi_{cc}^{+},\Omega_{cc}^{+}$) and light-
flavor pseudoscalar
mesons ($\pi,K,\eta$) up to the next-to-leading order within
chiral effective theory. We perform the unitarization of the $S$-wave scattering amplitudes in order to study the excited doubly charmed
baryons. The unknown next-to-leading order low energy constants are determined through the fits to recent
lattice data in the elastic scattering processes based on the CLQCD ensembles. Following the
chiral extrapolation to physical
quark masses, we predict resonance, virtual and bound doubly-charmed-
baryon states arising from the single- and coupled-channel scattering of $\Xi_{cc}^{++},\Xi_{cc}^{+},\Omega_{cc}^{+}$ with $\pi,K,\eta$. Furthermore, we also calculate the corresponding scattering lengths, effective ranges, phase shifts and inelasticities at physical
quark masses, which could shed light on future experimental searches and
lattice simulations.
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Instrumentation and Methods for Astrophysics
Improving Beam Quality in Gravitational-Wave Interferometers Illuminated by Higher-Order Laguerre-Gaussian Modes
Liu Tao, Yuefan Guo, Alberto Gatto et al. (+5 more)
Higher-order Laguerre-Gaussian (LG)
laser modes have been proposed to reduce test-mass thermal noise in
laser interferometric gravitational-wave detectors, owing to their more homogeneous intensity profiles compared to the currently employed fundamental Gaussian beam. However, LG beams such as the LG$_{3,3}$ mode suffer significant beam quality degradation in Fabry-Perot arm cavities in GW detectors with realistic state-of-the-art mirror surface figure errors, due to scattering into degenerate modes of the same order, which are resonantly enhanced by shared cavity resonance conditions. In this work, we investigate an alternative ”donut-shaped” LG$_{0,\ell}$-like mode, specifically the LG$_{0,6}$ mode, and demonstrate strategies to improve its performance. These include the introduction of a tailored circular mirror mask with anti-reflective coating in the central region, which selectively increases the losses of parasitic degenerate modes while minimally impacting the LG$_{0,6}$ mode due to its limited overlap with the masked area. We further assess the marginal benefits of anticipated improvements in mirror surface figure errors and the potential reduction of cavity finesse. We demonstrate that these strategies can reduce the average contrast defect by more than two orders of magnitude and lower the mode loss by nearly a factor of five, achieving performance at or below the typical values observed in current detectors. This work opens up new research and development pathways for employing LG$_{0,\ell}$-type modes that achieve significant thermal noise reduction while maintaining beam quality and optical performance comparable to current gravitational-wave interferometers.
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All authors Liu Tao, Yuefan Guo, Alberto Gatto, Eleonora Capocasa, Jérome Degallaix, Massimo Granata, Matteo Tacca, Matteo Barsuglia
Instrumentation and Methods for Astrophysics
Operational capabilities and on-sky performance of SAMOS at the completion of science commissioning
Massimo Robberto, Stephen A. Smee, Robert H. Barkhouser et al. (+9 more)
We present the operational capabilities and on-sky performance of the SOAR Adaptive Module Optical Spectrograph (SAMOS) at the completion of its science commissioning phase. SAMOS is a Digital Micromirror Device (DMD)-based multi-object spectrograph and imager installed behind the SOAR Adaptive Module (SAM) ground-layer adaptive optics system. The instrument relays the full 3 x 3 arcmin AO-corrected field onto a large-format DMD, where each micromirror can direct light to either a spectroscopic or a parallel imaging channel. This architecture enables programmable slit-mask patterns that can be generated and reconfigured within seconds. SAMOS provides low-resolution spectroscopy over the 4000-10000 A wavelength range at resolving power R ~ 2500 and high-resolution spectroscopy (R ~ 10,000) in the 4500-5150 A and 6 000-7000 A bands. We summarize the operational workflow established during commissioning, including target acquisition, astrometric registration, DMD slit-mask generation, simultaneous imaging and spectroscopy, and automated data reduction. Science-verification observations demonstrate accurate target acquisition, reliable programmable slit-mask operation, multiplexed spectroscopy of crowded
stellar fields, wavelength-calibration accuracy of about 0.3 A, and end-to-end spectrophotometric calibration through the combination of imaging and spectroscopic data. These results establish SAMOS as a unique facility instrument that combines adaptive-optics-assisted imaging, programmable multi-object spectroscopy, and rapid slit-mask reconfiguration for efficient spectroscopic surveys, transient follow-up, and studies of crowded
stellar populations.
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All authors Massimo Robberto, Stephen A. Smee, Robert H. Barkhouser, Stephen C. Hope, John J. Piotrowski, Dana Koeppe, Mario Gennaro, Zoran Ninkov, Megan E. Donahue, Andrei Tokovinin, Randolph P. Hammond, Albert J. Harding
Nuclear Experiment
Precision measurement of radiative neutron e̱ta}-decay: methodology and systematic effects
J.S. Nico, R. Alarcon, M.J. Bales et al. (+18 more)
In the Standard Model the free
neutron decays to a
proton, an electron, and an antineutrino along with a continuous spectrum of
photons. In 2016 the RDK II collaboration reported on a measurement of the
photon energy spectrum and branching ratio over the range of 0.4 keV to the 782 keV endpoint using two different detector arrays. In the experiment, the radiative decay
photons were observed in coincidence with the decay electrons and
protons. In this paper, we present details of the analysis, including the determination of the systematic corrections and uncertainties and comparison of measured particle and
photon energy spectra to Monte Carlo simulations. We conclude with approaches to improving the precision of these measurements.
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All authors J.S. Nico, R. Alarcon, M.J. Bales, C.D. Bass, E.J. Beise, H. Breuer, T.E. Chupp, K.J. Coakley, R.L. Cooper, M.S. Dewey, S. Gardner, T.R. Gentile, T.E. Haugen, D. He, S.F. Hoogerheide, H.P. Mumm, B. O'Neill, J.W. Paster, T. Rao, A.K. Thompson, F.E. Wietfeldt
Optics
Comb-enabled spectral-domain image transport through perturbation-prone multimode fibers
Maohan Li, Zijian Wang, Bowen Sun et al. (+9 more)
Multimode fibers (MMFs) offer a compact platform for imaging, sensing, and information transport, but their practical deployment is hindered by sensitivity to fiber perturbations, which alter modal coupling and invalidate conventional speckle-based calibrations. Here, we demonstrate perturbation-resilient image transport through MMFs by combining image-to-spectrum encoding with dual-comb spectroscopy. Two-dimensional images are converted into comb-line-resolved spectral signatures before fiber transmission, allowing spatial information to be carried in the spectral domain rather than in the output speckle field. After propagation, dual-comb heterodyne detection maps the encoded spectrum into the
radio-frequency domain, enabling massively parallel spectral readout with a single photodetector. Neural-network-assisted compressive reconstruction further enables high-fidelity imaging from sparse, noisy, and spectrally aliased measurements. Our approach achieves Pearson correlation coefficients exceeding 0.9 under strong fiber perturbations and supports frame rates up to 2.5 MHz, allowing the observation of transient switching dynamics in a digital micromirror device. These results establish a powerful tool for robust, real-time image transport through flexible MMFs, with potential applications in remote sensing and fiber-based optical instrumentation.
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All authors Maohan Li, Zijian Wang, Bowen Sun, Zhuoren Wan, Xiangze Ma, Xiuxiu Zhang, Yuan Chen, Mei Yang, Qi Wen, Zhaoyang Wen, Ming Yan, Heping Zeng
Cosmology and Nongalactic Astrophysics
Cosmology with Intensity Mapping via Statistics Beyond the Power Spectrum in the SKAO Era
Suman Majumdar, Debanjan Sarkar, Leon Noble et al. (+38 more)
The cosmological distribution of neutral hydrogen (HI) during the post-reionization era is highly non-Gaussian due to the underlying non-linear structure formation, complex
galaxy biasing, and potential
primordial non-Gaussianity. One needs higher-order (beyond two-point) statistics to maximally extract the non-Gaussian information out of the 21-cm intensity maps. This chapter summarizes the potential of several higher-order statistics, including voxel intensity distribution, emission line stacking, probability density functions, $\ell_1$-norm, bispectrum, and various marked statistics. Additionally, image-based morphological descriptors, such as the Largest Cluster Statistic, local dimensions, and Minkowski functionals, etc., can potentially characterize the morphology and geometry of the
cosmic web encoded in the 21-cm intensity maps. This chapter presents forecasts of the detectability of these higher-order statistics in the context of the future SKAO observations. These forecasts incorporate instrumental noise, observational effects, and, in some cases, foreground removal in their analyses. With its unprecedented sensitivity, the future SKAO 21-cm observations will enable us to measure these higher-order statistics more precisely, possibly helping to break degeneracies between astrophysical and cosmological parameters, and maximizing the science outcome from these surveys.
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All authors Suman Majumdar, Debanjan Sarkar, Leon Noble, Manas Mohit Dosibhatla, Zhaoting Chen, Bernhard Vos-Ginés, Vishrut Pandya, Mohd Kamran, Sourav Pal, Chandra Shekhar Murmu, Cora Uhlemann, Pauline Gorbatchev, Jean-Luc Starck, José Luis Bernal, Marta Spinelli, Caroline S. Heneka, Matteo Viel, Gabriella De Lucia, Fabio Fontanot, Stefano Camera, Steve Cunnington, Benedetta Spina, Dionysis Karagiannis, Samit Kumar Pal, Anshuman Tripathi, Sarah Libanore, Abinash Kumar Shaw, Rajesh Mondal, Yashrajsinh Mahida, Yashar Akrami, Philip Bull, Chris Clarkson, Abhirup Datta, José Fonseca, Yin-Zhe Ma, Roy Maartens, Liantsoa F. Randrianjanahary, Martin Sahlen, Xin Wang, Yougang Wang, Jochen Weller
Optics
Arduino based interferometer stabilizer equipped with a digital lock-in amplifier
Giuseppe Emanuele Lio, Saravanan Rajamani, Alessandro Pitanti et al. (+2 more)
Interferometric sensors are ubiquitous in precision metrology, yet their performance is fundamentally limited by environmental noise and thermal drift. To achieve maximum sensitivity, these systems must be actively stabilized at the quadrature point of the interference fringe. Commercial stabilization solutions, typically based on analog lock-in amplifiers or FPGA architectures, are often prohibitively expensive and do not not offer the flexibility needed for custom experimental setups. In this work, we present an open-source, compact and low-cost digital stabilization system built upon the dual-core Arduino Giga R1 microcontroller. The system features a custom analog front-end with programmable gain amplifiers (PGAs) and active signal conditioning, enabling direct integration with standard amplified photodiodes. We implement a firmware-based digital lock-in amplifier running at a 100 kHz sampling rate, which performs real-time demodulation and PID feedback control without the latency bottlenecks of PC-based loops. Experimental characterization demonstrates that the system effectively suppresses long-term thermal drift and actively rejects external perturbations. The resulting device provides a standalone, Arduino-based alternative for
laser frequency stabilization and interferometric control in educational and research laboratories.
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All authors Giuseppe Emanuele Lio, Saravanan Rajamani, Alessandro Pitanti, Stefano Roddaro, Simone Zanotto
General Relativity and Quantum Cosmology
Orbital, Shadow, and Thin-Disk Signatures of a Regular Black Hole with Gravitational Self-Energy
Erdinç Ulaş Saka
We investigate geodesic motion, shadow observables and thin-disk
accretion for the regular black hole generated by a non-local gravitational self-energy contribution. The geometry is controlled by a zero-point length and can be followed smoothly from the Schwarzschild limit to a cold extremal remnant. We compute the
photon ring, critical impact parameter, apparent shadow radius, null Lyapunov exponent, innermost stable circular orbit, orbital frequencies and Novikov-Thorne flux profile. As the self-energy scale grows, both the
photon ring and the ISCO move outward, while the
photon-ring frequency and instability exponent decrease. The horizon-normalized shadow area increases by about a factor of 2.7 for the near-extremal
benchmark, although the same shadow radius decreases when normalized by the ADM mass. The ISCO binding efficiency grows modestly, whereas the zero-torque thin-disk flux peak moves outward and falls to about 61% of the Schwarzschild peak as the solution approaches the remnant regime. These trends identify a coherent set of optical, orbital and
accretion signatures of the gravitational-self-energy regularization.
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Quantum Gases
Spin-orbit coupling induced geometric squeezing in rotating Bose-Einstein condensates
Fei Zhu, Chunxia Guo, Rui Zhang et al. (+3 more)
Squeezed states play a key role in diverse frontiers of
quantum physics. Geometrically squeezed states, a squeezed state in the orbital phase space of rotating Bose-Einstein condensates (BEC), have been conventionally generated by anisotropic trapping potentials. In this work, we propose a different route to generate
geometric squeezing via
spin-orbit coupling (SOC) in a pseudospin-1/2 BEC. We show that the SOC enables effective two-
phonon transitions within the lowest Landau level via virtual
spin-flip processes, leading to exponential squeezing dynamics in both
spin components. Furthermore, by applying a $\pi/2$
spin rotation, the two
spin channels can be coherently coupled to produce two-mode
geometric squeezing. We also investigate the influence of interatomic interactions on squeezing performance and identify parameters where robust squeezing can be achieved. Our work provides a viable pathway to realize and manipulate
geometric squeezing in spinor
quantum gases.
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All authors Fei Zhu, Chunxia Guo, Rui Zhang, Lianghui Huang, Ren Zhang, Li Chen