Astrophysics of Galaxies
Detection of the Polycyclic Aromatic Hydrocarbon Phenalene (C$_{13}$H$_{10}$) in the Very Low Luminosity Object (VeLLO) MC27/L1521F
Gabi Wenzel, Thomas H. Speak, Ci Xue et al. (+12 more)
To date, 14 polycyclic aromatic hydrocarbons (PAHs) ranging in size from two to seven (including five- and six-membered) carbon rings have been detected in the starless dense core TMC-1 CP within the Taurus molecular cloud. Their detection raises questions about the distribution of PAHs in the cold interstellar medium (ISM) and their
evolution during
star formation. Here, we present the first interstellar detection of a three-ring PAH outside of TMC-1 CP. We detect phenalene (C$_{13}$H$_{10}$), a compact, peri-fused PAH, in the dense core MC27/L1521F, a molecular cloud in Taurus containing a very low-luminosity object (VeLLO). We compare the abundances of phenalene in the two sources with respect to the single-ring aromatic benzonitrile, and find that it is enhanced by a factor of four in MC27/L1521F. We discuss the implications for possible formation and destruction pathways in the two sources. These findings further support the widespread abundance of PAHs throughout the cold ISM and are consistent with survival, inheritance, or replenishment during the earliest stages of
star formation.
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All authors Gabi Wenzel, Thomas H. Speak, Ci Xue, Edwin A. Bergin, Andrew M. Burkhardt, Martin A. Cordiner, Miya Duffy, Zachary T. P. Fried, Andrew Lipnicky, Christopher N. Shingledecker, Reace H. J. Willis, Anthony J. Remijan, Michael C. McCarthy, Brett A. McGuire, Ilsa R. Cooke
Quantum Physics
Quantifying randomness with measurement incompatibility
Sebastian Schlösser, Pauli Jokinen, Martin Plávala et al. (+3 more)
We present a trade-off between the amount of observed measurement incompatibility and the capabilities of a classical Eavesdropper in a prepare-and-measure scenario. The result is based on a qualitative connection between measurement incompatibility and randomness generation together with the utilization of incompatibility witnesses as randomness certificates. This allows one to use a
geometric measure of incompatibility, the generalised robustness, to bound Eve's strategies through a semi-definite program, while providing an explicit protocol for generating randomness from any set of incompatible measurements. By translating the result to
quantum steering, we find a tight connection between steerability and randomness generation in a setting using any finite number of measurement inputs. We further show how our techniques can be generalised to scenarios where Eve has a
quantum memory by using a dimensional generalisation of joint measurability.
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All authors Sebastian Schlösser, Pauli Jokinen, Martin Plávala, Leevi Leppäjärvi, Leonardo S. V. Santos, Roope Uola
High Energy Astrophysical Phenomena
H\alpha\ clarifies picture of IIn supernova SN 2015da
Nikolai Chugai
Observational data on type IIn
supernova SN 2015da are revisited to clarify some ambiguous issues of this phenomenon. The H alpha–emitting site is found to switch around day 90 from the circumstellar matter to the unshocked ejecta. This picture makes it possible to recover the expansion velocity of late time ejecta and to locate the
dust formation in the inner zone of unshocked ejecta.The bolometric light curve and expansion velocities combined with modelling the circumstellar interaction imply that the
supernova exploded with an energy of $\gtrsim 4\times10^{51}$ erg inside the circumstellar envelope with the mass of $\approx 14$ Msun. The recovered density of the circumstellar matter is consistent with the Thomson optical depth inferred from H alpha modelling on day 46.The observed circumstellar envelope is produced by an average mass loss rate of 0.035 Msun/yr during 400 yr before the
supernova explosion.
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Physics and Society
Dynastic dynamics: Modelling powerful naming choices with stochastic prestige
Pablo Rosillo-Rodes, Santiago Lamata-Otín, David Soriano-Paños et al. (+2 more)
The naming choices of powerful rulers encode millennia of cultural, political, and institutional influences. Consequently, the long-term onomastic dynamics within some of the most powerful dynasties cannot be explained by simple mechanisms such as frequency-dependent reinforcement or random name reuse. Here, we propose a minimal model that encapsulates these influences in a single highly
stochastic variable, prestige, and assume that name selection is driven by the prestige accumulated by previous rulers bearing the same name within each dynasty. Using an extensive
dataset spanning ten dynasties, we show that the model reproduces the pronounced inequalities in name frequencies, the long-term persistence of dominant names, and the abrupt rises in popularity observed in historical records. Our results suggest that the naming traditions of powerful rulers preserve institutional
memory through reinforcement while remaining sensitive to rare historical events that can reshape the hierarchy of names across generations.
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All authors Pablo Rosillo-Rodes, Santiago Lamata-Otín, David Soriano-Paños, Laurent Hébert-Dufresne, Peter Sheridan Dodds
Quantum Physics
Low-latency FPGA-based electronic control system for fast preparation of defect-free atom arrays
Ya-Dong Hu, Dong-Qi Ma, Tian-Yang Zhang et al. (+13 more)
The scalability of neutral atom
quantum computing demands integrated electronic control systems with low latency, modular architecture, and real-time feedback capability. Here, we present an FPGA-based electronic control system that eliminates the PC from the feedback loop, integrating
photon counting, real-time decision-making, and waveform generation within a unified PXIe architecture. The system achieves a total feedback latency of $282\,\mathrm{\mu s}$ and is validated in practical experiments by assembling defect-free atom arrays from 24 stochastically loaded optical tweezers. A single-round rearrangement achieves a filling fraction of $\sim96\%$, while feedback-controlled iterative rearrangement over five rounds boosts the success probability for generating a 10-atom defect-free array from $65.7\%$ to $95.4\%$. This system establishes the electronic infrastructure necessary for mid-
circuit measurement and real-time
quantum error correction on neutral-atom platforms.
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All authors Ya-Dong Hu, Dong-Qi Ma, Tian-Yang Zhang, Liang Chen, Yi-Chen Zhang, Xiao-Kang Zhong, Wen-Yi Zhu, Hong-Jie Fan, Qing-Xuan Jie, Yan-Lei Zhang, Gang Li, Xi-Feng Ren, Xu-Liang Zhang, Guang-Can Guo, Zhu-Bo Wang, Chang-Ling Zou
Quantum Physics
Instability of the undecidable behavior of the spectral gap in 1D
Laura Castilla-Castellano and Angelo Lucia
The problem of determining the existence of a spectral gap in a
lattice quantum spin system was previously shown to be undecidable for one [J. Bausch et al., "Undecidability of the spectral gap in one dimension", Physical Review X 10 (2020)] or more dimensions [T. S. Cubitt et al., "Undecidability of the spectral gap", Nature 528 (2015) and Forum of Mathematics Pi, 10 (2022)]. In this work, we focus on the 1-dimensional result, showing that the constructed family with undecidable behavior is extremely sensitive to perturbations. In particular, for any $\varepsilon > 0$, there exists a 1-local, rank 1, perturbation with norm $O(\varepsilon)$, such that the spectral gap problem for the family in [J. Bausch et al., "Undecidability of the spectral gap in one dimension", Physical Review X 10 (2020)] now becomes decidable.
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High Energy Physics (Theory)
Seiji Terashima
Bulk reconstruction is a central problem in AdS/CFT, and
entanglement wedge reconstruction is its subregion version. We argue that this subregion statement should be separated from the stronger
holographic quantum error correction interpretation, in which one region-independent logical bulk operator has code-preserving representatives in several boundary regions. A simple locality argument shows that such a common reconstruction must commute with the code-preserving local
algebras in the complementary regions. This is the mechanism realized in HaPPY-type codes: the erased regions are blind to a protected logical
algebra. An ordinary finite $N$
holographic CFT does not have such a protected invisible sector for supergravity fields. Its low-energy local observables, in particular, suitably smeared stress tensors, detect the physical support and gravitational dressing of ordinary bulk operators, up to possible center or superselection data. Thus, there is no such
holographic quantum error correction and the $N=\infty$ agreement of global and subregion HKLL formulae is a free-theory statement. What remains is
entanglement wedge reconstruction without
holographic quantum error correction, or subregion complementarity: each boundary region has its own code-preserving low-energy
algebra and its own region-adapted bulk interpretation, rather than a shared logical operator.
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Materials Science
Complex polar superstructure controlled thermal conductivity in ferroelectric PbTiO3/SrTiO3 superlattices
Noa Varela-Domínguez, Marcel S. Claro, Araceli Gutiérrez-Llorente et al. (+8 more)
Integrating epitaxial thin films of ferroelectric PbTiO3 and paraelectric SrTiO3 into artificially layered periodic superlattices provides a unique platform for tuning strain, depolarization, and interfacial/surface energies, thereby accessing a rich phase diagram of topological polar structures (skyrmions,
vortices, merons, or sinusoidal waves) and superstructures (polar supercrystals). Here we show that the 3D arrangement of polar
vortices in a supercrystal suppresses thermal conductivity (k) of PTO/STO superlattices (SLs). The temperature dependence of k reflects the
evolution of the polar superstructure, as determined by X-ray diffraction and transmission electron microscopy. The comparison with other SLs suggests that the 3D arrangement is crucial for controlling thermal conductivity beyond the usual interfacial scattering. Moreover, we observed an unexpected reduction in thermal conductivity with increasing superlattice thickness, a phenomenon reminiscent of
phonon-wave Anderson localization. Our results show that complex polar superstructures can be useful active elements for modulating heat transport in technologies where control over heat dissipation is critical.
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All authors Noa Varela-Domínguez, Marcel S. Claro, Araceli Gutiérrez-Llorente, Eric Langenberg, Xinxin Hu, Núria Bagués, Anthony Edgeton, Chang Beom-Eom, Jordi Arbiol, José Santiso, Francisco Rivadulla
Mesoscale and Nanoscale Physics
Magnetophonon Resistance Oscillations in Structures with a GaAs Quantum Well and Barriers of AlAs/GaAs$\langle\delta$-Si$\rangle$ Superlattices
I. L. Drichko, I. Yu. Smirnov, M. O. Safonchik et al. (+3 more)
Magnetophonon resistance oscillations (MPR) associated with the resonant scattering of electrons by optical
phonons at temperatures of 77-240 K, as well as resonant scattering of electrons by acoustic
phonons (PIRO) at temperatures of 10-25 K, were investigated in the same samples featuring a GaAs
quantum well and AlAs/GaAs superlattice barriers doped with Si. The study of MPR demonstrated that resonant electron scattering occurs on bulk longitudinal optical
phonons and does not depend on the dimensionality of the system or inter-subband transitions in systems with two subbands of size quantization. However, the amplitude of the oscillation with number $N=1$ in two-dimensional structures depends on the interplay of scattering mechanisms, which, in turn, is influenced by the structure of the system. As for PIRO, in samples with two size quantization subbands, resonant electron scattering by longitudinal acoustic
phonons is observed against the background of inter-subband transitions (MISO), leading to their interference.
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All authors I. L. Drichko, I. Yu. Smirnov, M. O. Safonchik, M. A. Shakhov, A. K. Bakarov, A. A. Bykov
Plasma Physics
Precision mapping of laser-driven magnetic fields and their evolution in high-energy-density plasmas
Lan Gao, PM Nilson, IV Igumenshchev et al. (+4 more)
Magnetic fields generated by the Rayleigh-Taylor instability were measured in
laser-accelerated planar foils using ultrafast
proton radiography. Thin plastic foils were irradiated with $\sim$4-kJ, 2.5-ns
laser pulses focused to an intensity of $\sim$10$^{14}$ W$/$cm$^{2}$ on the OMEGA EP
Laser System. Target modulations were seeded by
laser nonuniformities and amplified during target acceleration by the Rayleigh-Taylor instability. The experimental data show the hydrodynamic
evolution of the target and MG-level
magnetic fields generated in the broken foil. The experimental data are in good agreement with predictions from 2-D magnetohydrodynamic simulations.
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All authors Lan Gao, PM Nilson, IV Igumenshchev, MG Haines, DH Froula, R Betti, DD Meyerhofer
Fluid Dynamics
Drift of interfaces in forced stably-stratified turbulence and the role of vertically-sheared helical structures
Niccolò Cocciaglia, Luca Biferale, Fabio Bonaccorso et al. (+1 more)
Experimental investigations of forced stably stratified
turbulence (SST) have shown that the step-like density profile, made of well-mixed density layers and sharp interfaces alternating along the
gravity direction, undergo a slow coarsening dynamics with either decay or merging of interfaces. In this Letter, we focus on the coarsening dynamics phenomenon, by means of Direct Numerical Simulations of forced SST at moderate resolutions, and very long temporal integration. We show that the vertical drift and merging of interfaces is associated to the emergence of spatially-uniform, vertically-sheared helical structures that break the mirror-
symmetry of the system. When these are absent, interfaces decay is observed instead. %how the kinetic energy excursions observed at $Fr=0.076$, occurring in parallel to vertical drift of interfaces, are due to the emergence of spatially-uniform, vertically-sheared helical structures that break the mirror-
symmetry of the system. This is absent at larger $Fr=0.22$, where interface decay is observed instead. A dynamical correspondence between helicity dissipation rate by buoyancy effects and the vertical buoyancy flux allows to establish a (causal) connection between the
chiral structures and the vertical movement of interfaces leading to merging.
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All authors Niccolò Cocciaglia, Luca Biferale, Fabio Bonaccorso, Alessandra S. Lanotte
Statistical Mechanics · Cross-listed from math.CO
Twofold universality of large-$N$ melonic random tensors
Carlos I. Perez-Sanchez
We construct a measure that exhibits two aspects of a new type of universality and dramatically simplifies the integration of tensors $T_{a_1,a_2,\ldots,a_D} \in \mathbb{C}$ ($a_1,\ldots,a_D=1,\ldots,N$) at large $N$. In contrast to
matrix integration, in which
matrix traces canonically yield the integrand, tensors need additional information (equivalent to a $D$-coloured graph $B$) to contract their indices and form a tensor trace $B(T)$. We show that, whenever each $B_1,\ldots, B_n$ can be obtained by a recursive construction known as melonicity, then the leading order in $N$ of the integral of $ {B_1}(T) {B_2}(T) \cdots {B_n}(T) $ is independent of the – often intricate – combinatorics of the traces $B_i$, but also, to our surprise, independent of $D$ as far as $D\geq 3$. Instead, at large $N$, these integrals are some functions (indexed by $n$) of the number of vertices $2p_i$ of $B_i$ which we call melonic
polynomials. Melonic traces cumulants with respect to any ('interacting') measure \[ \exp\Big\{-N^{D-1} \sum_{i=1}^m g_i {B_i}(T)\Big\} \mathrm{d}\mu_0(T) \quad (g_1,\ldots,g_m \in \mathbb{R}, \mathrm{d}\mu_0(T) =\text{the tensor Gaussian}) \] with each $B_i$ melonic, can be computed with our universal measure that replaces each $B_i$ by a canonical trace depending only on $p_i$. We prove that any two melonic tensor models are indistinguishable at large-$N$, independently of the number of tensor indices (first universality aspect), and of the fine-grainedness of their interactions (second universality), being a sufficient condition that the couplings (the parameters $g_i$ above) agree and their respective traces are monomials with the same degree in $T$.
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Chaotic Dynamics
Chaos in the Order of Finite Bernoulli Convolutions
Nadav Shrayer
In this note we explore numerically the finite Bernoulli convolutions. We show that with a suitable choice of parameter, it might serve as a toy model for intermittent energy cascade in fully developed
turbulence. We then show how the crossings of $\beta$-expansions distribute in $\beta$, and suggest that it might highlight the parameters with enhanced overlap structure that are related to measures that are singular continuous. We later introduce a notion of order to the $\beta$-expansions based on the lexicographical order of the $N$-binary words, and observe that for most sampled adjacent pairs when $\beta=2$, the distance in their order increases exponentially when $\beta$ decreases from 2 to 1. This suggests 'chaotic' behavior, with the 'Lyapunov exponents' bunched into several clusters that depend on $N$. We end the note with some 'order plots' and an interesting connection between the finite $\beta$-compactum with $\beta=g$ (g being the golden ratio) and binary reflected Gray code.
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Fluid Dynamics
Inverse Transfer and Coherence in Rotating Stratified Flow with Clouds and Phase Transitions
Yeyu Zhang, Yingshuo Peng and Leslie M. Smith
Inverse energy transfer to large-scale coherent structures in idealized models of geophysical flows has been of interest for over four decades. Extensive knowledge exists regarding inverse transfer in rotating and stratified dry dynamics, characterized by the Rossby number and a single dry Froude number. The current study includes effects of water and phase changes, with dynamics characterized by the Rossby number and two Froude numbers for unsaturated and saturated environments. Using numerical computations with random forcing, inverse energy transfer is examined for a model with a Boussinesq dynamical core, incorporating water vapor and
liquid water in the limit of asymptotically-fast cloud microphysics. Besides kinetic energy, total energy includes buoyant potential energies from each phase, and latent moist energy responsible for potential energy transfer at phase boundaries. The rotation and stratification terms are large and comparable, such that the dry version of the
evolution equations is dominated by inverse transfer of pseudo potential vorticity(PV). For fixed Rossby and dry (unsaturated) Froude numbers, compared to dry dynamics, there is a reduction in energy transfer rate, associated with the larger Froude number of saturated regions. The upscale transfer to moist PV is influenced by nonlinear waves at lowest order resulting from nonlinear buoyancy near phase interfaces. These nonlinear waves lead to coherent updrafts and downdrafts roughly aligned with fuzzy, large-scale phase boundaries identified by the time average of a cloud indicator function. Statistical relationships between phase boundaries, updrafts/downdrafts and moist PV are explored in flow regions dominated by moist PV-
vortices.
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Physics and Society
Statistical inference of dynamical processes on networks
Javier Ureña-Carrion, Tiago P. Peixoto and Gerardo Iñiguez
Mechanisms of interaction in spreading models are central to our quantitative understanding of networked contagion processes, from disease transmission to opinion dynamics. Yet, while empirical data can reveal who interacts with whom, they rarely provide direct information about how interactions drive spreading, leaving the underlying mechanism to be inferred from observed dynamics, and selected among competing hypotheses. We propose a general framework for model selection in binary-state spreading processes on networks and show that asymptotic approximations in the thermodynamic limit can accurately predict inference outcomes in finite systems. By systematically exploring a broad parameter space, we characterize the detectability of six archetypal spreading mechanisms commonly used in the literature and find that accuracy generally increases in sparse networks, which are prevalent in real-world systems, and near phase transitions, such as the epidemic threshold of simple contagion processes. We further assess the prevalence of these mechanisms across a diverse set of empirical
datasets, highlighting the impact of data preprocessing on model recovery. Our results show that statistical model selection can fail under common conditions and suggest new directions for overcoming these limitations.
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High Energy Physics (Phenomenology)
Analysis of Nuclear Fragmentation Functions for Pions with $A$ and $\nu$ Dependence
Mengyang Li, Zijian Ye, Jun Gao et al. (+3 more)
We present a QCD analysis of pion
nuclear fragmentation functions (nFFs), which encode
nuclear modifications to hadronization in high-energy
nuclear collisions. Within this framework,
vacuum fragmentation functions and their
nuclear modifications are extracted simultaneously. The
nuclear effects are parameterized as functions of the mass number $A$, the energy of the fragmenting parton in the target rest frame $\nu$, and the
hadron energy fraction $z$, allowing their dependence on these variables to be quantified. Our analysis includes semi-inclusive deep-inelastic scattering data on
nuclear targets, with kinematic cuts chosen to ensure the applicability of perturbative QCD and collinear factorization. The resulting fit provides a good description of most
datasets, with the nFFs well constrained in the energy fraction range $z \in [0.2, 0.7]$. Additionally, with our new nFFs, we present next-to-leading order predictions in $pp$ and $pA$ collisions, which show reasonable agreement with ALICE data within the current experimental uncertainties.
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All authors Mengyang Li, Zijian Ye, Jun Gao, Xiaomin Shen, Hongxi Xing, Yuxiang Zhao
Materials Science
Microwave Studies of Single Crystal TeO2 at Cryogenic Temperatures
Timothy Holt, Maxim Goryachev, William Campbell et al. (+1 more)
We use whispering-gallery-mode analysis to characterise the microwave dielectric properties of single-
crystal TeO$_2$ at cryogenic temperatures and compare its loss performance with other low-loss dielectric materials. Finite-element modelling is combined with measurements at room temperature, 4 K, and 20 mK to develop accurate cryogenic simulations and extract the anisotropic dielectric permittivities, giving $\varepsilon_\parallel=25.75\pm0.08$ and $\varepsilon_\perp=20.90\pm0.07$. Loss measurements reveal quality factors as high as $9\times10^6$ and minimum loss tangents approaching $3\times10^{-8}$, placing TeO$_2$ among promising low-loss dielectrics for cryogenic microwave applications. Electron-
spin-resonance spectroscopy further indicates a clean
spin environment, while identifying distinct
spin systems consistent with the known properties of the
crystal.
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All authors Timothy Holt, Maxim Goryachev, William Campbell, Michael E. Tobar
Materials Science
Best Practices for First-Principles Modeling of Amorphous Oxide Semiconductors: A Statistical Framework and Application to Zn-Sn-O
Michiel J. van Setten, Tonglin L. Newsom, Christopher Pashartis et al. (+3 more)
Ternary and quaternary amorphous
oxide semiconductors have many properties that make them promising candidates for use in electronic applications like display,
memory, and back end of line logic. However, finding the right material for a given application and optimizing its properties, deposition, and integration, requires a thorough understanding of the physics and chemistry at play. When properly carried out, first principles computations can play a crucial role in enhancing this understanding. In this work, we highlight several pitfalls often observed in research applying these computations, with the Zn-Sn-O system as an example. We show that a proper understanding of the fundamental differences between the physics of the crystalline and amorphous or disordered phases is crucial, as is a proper statistical sampling of structural models. For the Zn-Sn-O system we conclude that from a performance point of view, mobility and initial threshold voltage, it is a promising material class. However, our computed results show that a similar sensitivity to hydrogen induced doping may be present as in IGZO.
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All authors Michiel J. van Setten, Tonglin L. Newsom, Christopher Pashartis, Vera van Noort, Rebecca L. Peterson, Geoffrey Pourtois
High Energy Physics (Phenomenology)
Leptogenesis and Low Reheating Temperatures
Marcos A. G. Garcia, Stephen E. Henrich, Wenqi Ke et al. (+1 more)
We study leptogenesis during non-instantaneous reheating in the canonical type-I seesaw framework, with the dominant source of right-handed
neutrino (RHN) production being non-thermal from inflaton decays ($\phi \rightarrow NN$). While matter-like reheating ($w_\phi=0$) fails to be compatible with standard leptogenesis for very low reheating temperatures, the situation is strikingly different for generalized Starobinsky potentials approximated by $V(\phi)\propto\phi^k$ with $k\geq4$ about the minimum. In the latter cases, the observed
baryon asymmetry can readily be obtained for arbitrarily low reheating temperatures above the BBN bound of $\sim4$ MeV. We study radiation-like reheating ($w_\phi=1/3$, $k=4$) in detail, showing that the evolving effective mass of the inflaton condensate leads to kinematic shutoff of the $\phi\rightarrow NN$ channel, which qualitatively changes the leptogenesis dynamics. We include a detailed treatment of the effects of fragmentation of the inflaton condensate. The final
baryon asymmetry depends primarily on only two parameters: the inflaton-RHN coupling, $y_{\phi NN}$, and the CP-violating parameter $|\epsilon|$. Interestingly, the final asymmetry is largely insensitive to the RHN mass, the reheating temperature, and the RHN decay rate. While we focus on fermionic reheating, we show that the general features of these results also hold for bosonic reheating to scalars.
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All authors Marcos A. G. Garcia, Stephen E. Henrich, Wenqi Ke, Keith A. Olive
High Energy Physics (Theory)
The Remnant of a Rotating Regular Black Hole from the Generalized Entropy in the Final Stage of Evaporation
Shingo Takeuchi
We express the generalized
entropy (GE) of the Hawking radiation in the final stage of an evaporating rotating regular black hole (BH) by writing the mass of the BH as $m_{\rm ext} + \alpha$, where $m_{\rm ext}$ represents the mass at the extremal limit and $\alpha$ is a parameter. Generally,
entropy is non-negative. Based on this fact, we assume that, in the GE considered in this study, the signs of the contributions from the area term and the correction term remain unchanged throughout the entire evaporation process of the BH. Therefore, we regard $\alpha$ at which the correction term vanishes as its lower bound and determine it. As a result, we find that such a value of $\alpha$ is finite. Denoting this value by $\alpha_2$, this result indicates that the mass of the BH cannot become smaller than $m_{\rm ext} + \alpha_2$, which can be interpreted as the emergence of a remnant at the final stage of BH evaporation. The BH considered in this study is a rotating regular BH. The regularization is motivated by the possibility that the fine structure of the central region becomes relevant in the final stage of evaporation. A rotating BH is considered from the viewpoint of generality.
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Nuclear Theory
Secondary Hadron–Nucleus Collisions of Short-Lived Hadrons in Ultra-Relativistic Fixed-Target Heavy-Ion Interactions
Sanatan Digal, P. S. Saumia and Ajit M. Srivastava
Ultra-relativistic heavy
nuclei traversing a solid target undergo successive
nuclear encounters separated by atomic
lattice spacings. At sufficiently high beam energies, Lorentz contraction reduces the proper time between collisions to $\mathcal{O}(10^4)$~fm$/c$ in the center-of-mass frame of the first interaction. We then consider the fragmentation region of this first collision, and show that short-lived
hadrons produced in this region, with additional Lorentz boost, can reach the next
nucleus before decaying. We show that this geometry enables secondary
hadron–
nucleus collisions involving species that cannot be realized as conventional secondary beams or in subsequent
hadron–
nucleus interactions in
cosmic-ray cascades. For a $2.76$ TeV-per-nucleon Pb beam incident on a solid Pb
lattice, we determine which forward-produced
hadrons can survive to a second interaction, estimate their collision probabilities, and analyze potential observable consequences. In particular, we identify some representative
hadrons whose proper lifetimes are of order $10^3$ fm/c, e.g. specific
mesons ($\eta^\prime$) and heavy-
flavor resonances ($J/\psi, D^*(2010)$), as projectile species that become accessible through this collision space-time geometry. At substantially higher beam energies (for example, with 10 TeV per-nucleon Pb beam), the survival probabilities are significantly enhanced. This can make even very short lived
hadrons with life times of few tens fm ( $\Xi(1530)$, $\omega(782)$, $\phi(1020)$) available for this secondary
hadron-
nucleus collision, providing an additional motivation for future ultra-relativistic fixed-target heavy-ion experiments.
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Astrophysics of Galaxies
VAPOLA – A multi-year, multi-band polarization survey of AGN and Sgr A* at mm wavelengths with ALMA I. Survey Overview and Science-Ready Archival Products
Alejandro Mus, Ciriaco Goddi, Douglas Carlos et al. (+13 more)
The Atacama Large Millimeter/submillimeter Array (ALMA) is the most sensitive interferometric array at millimeter and submillimeter wavelengths. Through the ALMA Phasing System (APS), it can participate in global Very Long Baseline Interferometry (VLBI) arrays, enhancing their sensitivity and resolution. However, processing and analzing the ALMA data obtained in APS mode during VLBI observations remains a complex task, requiring specialized expertise and time-consuming calibration and imaging procedures. In this paper, we present VAPOLA-the first online, multi-epoch, multi-band repository of high-level data products from ALMA observations of active
galactic nuclei (AGN) and Sgr A* during global VLBI campaigns. Built on an automated pipeline that processes fully calibrated ALMA (QA2) data, generates science-ready products with minimal user intervention. The repository includes fully calibrated interferometric visibilities, full-Stokes images across individual and combined spectral windows, polarimetric and spectral index maps, as well as tabulated polarimetric parameters from visibility-domain polarization fitting. By offering ready-to-use data through a user-friendly web portal, VAPOLA enables non-expert users to perform advanced science analyses without needing in-depth knowledge of ALMA procedures. This resource will facilitate a broad range of scientific investigations, including the characterization of
magnetic field properties in
accretion flows and relativistic jets, the structure and kinematics of dusty and molecular
tori in AGN, and absorption studies of the interstellar medium toward the
Galactic Center. In addition, the
dataset provides source-integrated parameters and calibration metadata essential for refining VLBI calibration and imaging workflows as well as for placing robust observational constraints on theoretical models of supermassive black holes and their environments.
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All authors Alejandro Mus, Ciriaco Goddi, Douglas Carlos, Vincenzo Galluzzi, Ezequiel Albentosa-Ruiz, Ivan Martí-Vidal, Hugo Messias, Kazi L. J. Rygl, Geoffrey B. Crew, Lynn D. Matthews, Elisabetta Liuzzo, Nicola Marchili, Raphael P. Rolim, Mariafelicia De Laurentis, Rocco Lico, Cristiano Urban
Quantum Physics
Temperature Beyond Equilibrium in Isolated Quantum Many-Body Systems and Their Subsystems
Maurizio Fagotti
Temperature is one of the central concepts of thermodynamics, yet its meaning far from
equilibrium remains unclear. The problem is especially challenging in isolated
quantum many-body systems, whose states evolve unitarily, may remain far from
equilibrium, and retain energy coherence, a genuinely
quantum feature with no direct classical counterpart. Specifically, energy fluctuations in a nonstationary
quantum state have two distinct origins. Part of these fluctuations comes from uncertainty in the energy populations and has the usual thermodynamic meaning. The rest comes from
quantum coherence between energy sectors and is responsible for the state's time dependence. We propose that, even away from
equilibrium, temperature identifies the state within the family of regular states sharing the same energy-coherence structure. The resulting inverse temperature is obtained from a principle of minimum discrimination information, which selects the least distinguishable state compatible with the prescribed energy and coherence structure. This replaces the usual maximum-
entropy principle, which, applied naively, can yield a biased
estimator of the inverse temperature. We also lay the groundwork for an extension of the construction to subsystems and show that, although the inverse temperature of a subsystem is not determined by its reduced state alone, under an
alignment assumption, its instantaneous rate of change is a local quantity for sufficiently large subsystems.
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Cosmology and Nongalactic Astrophysics
Can Distance Duality Violation Save Late-time Solutions to the Hubble Tension?
Yashi Tiwari, Ujjwal Upadhyay, Shao-Jiang Wang et al. (+1 more)
The discrepancy between early- and late-Universe determinations of the Hubble constant may point to physics beyond $\Lambda$CDM or to unaccounted-for systematics. Numerous late-time modifications to the expansion history have been proposed to alleviate this discrepancy, with limited success. Recent works have shown that, when the sound-horizon and
supernova calibrations are held fixed, any purely late-time resolution requires a violation of the
cosmic distance duality relation (CDDR). Recasting the tension in the $r_d$-$M_B$ plane, we show explicitly that distance duality, together with BAO and uncalibrated
supernova data and a fixed sound-horizon calibration, determines $H_0$ independently of the late-time expansion history. We then test the viability of the required CDDR violation by separately constraining reciprocity violation and
photon number non-conservation, deriving a new constraint on reciprocity-violating distortions of angular-diameter distances from BAO and
cosmic-chronometer data. Combining this result with existing
photon-number-conservation constraints, we find that the level of distance-duality violation needed to resolve the tension is strongly disfavoured by current data. We therefore conclude that, for fixed sound-horizon and
supernova calibrations, no modification confined to the late-time expansion history – even one violating distance duality – can resolve the Hubble tension, pointing instead toward early-Universe physics or unresolved local systematics.
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All authors Yashi Tiwari, Ujjwal Upadhyay, Shao-Jiang Wang, Vivian Poulin
Materials Science
Physical aging of glasses of an organic semiconductor
Shinian Cheng, Kritika Jha, Zijian Wang et al. (+5 more)
All glasses, including organic
semiconductor glasses, are non-
equilibrium materials whose properties will change with time. This physical aging process is poorly understood for organic
semiconductors, hindering the rational design of highly durable devices. In this study, we investigated the volume and enthalpy recovery processes in both thin films and bulk glasses of N,N'-Bis(3-methylphenyl)-N,N'-diphenylbenzidine (TPD). Our results revealed that volume recovery kinetics exhibit negligible dependence on film thickness for
liquid-cooled TPD films between 400 nm and 100 nm. Additionally, the volume recovery process in TPD films was strongly coupled to the enthalpy recovery observed in bulk TPD glasses during annealing near the glass transition temperature. Remarkably, TPD films prepared by physical vapor deposition at room temperature demonstrated exceptional resistance to physical aging, with an aging rate approximately one order of magnitude lower than that of their
liquid-cooled counterparts. These results not only enhance our understanding of the non-
equilibrium dynamics in amorphous systems but also offer valuable insights for the design of next-generation organic devices with significantly improved stability and durability.
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All authors Shinian Cheng, Kritika Jha, Zijian Wang, Juliana B. Lugo, Hayley Kositzke, John H. Perepezko, Zahra Fakhraai, Mark D. Ediger
General Relativity and Quantum Cosmology
Shadows and lensing signatures of a rotating black hole in a Hernquist dark matter halo
A. A. Araújo Filho, Arun Kumar, N. Heidari et al. (+3 more)
We investigate the optical properties of a rotating black hole immersed in a Hernquist dark matter
halo. The spacetime is generated from a static Hernquist black hole through the noncomplexification version of the Newman-Janis procedure, yielding a Kerr-like geometry whose
halo contribution is encoded in the radial function $\Delta(r)$ \cite{AraujoFilho:2026hernquist}. We derive the null geodesic equations, effective potentials, radial acceleration, and representative three-dimensional
photon trajectories around the event horizon and ergoregion. Using the separability of the Hamilton-Jacobi equation, we obtain the critical impact parameters of unstable spherical
photon orbits and construct the shadow contours for a distant observer. The rotation parameter mainly shifts and distorts the shadow, whereas the Hernquist
halo enlarges the
photon capture region and increases the apparent shadow size. Comparing the area-equivalent shadow diameter with the Event Horizon
Telescope measurements of Sgr A$^\ast$ and M87$^\ast$, we constrain the dimensionless
halo parameter $\hat{\rho}=M^2\rho$. The strongest restriction comes from Sgr A$^\ast$, giving $\hat{\rho}\sim(2.7-3.8)\times10^{-3}$ at $1\sigma$ and $\hat{\rho}\sim(4.1-5.2)\times10^{-3}$ at $2\sigma$. We also analyze strong- and weak-field gravitational
lensing. In the strong-field regime, the
halo shifts the unstable
photon orbit and critical impact parameter, controlling the logarithmic deflection angle and the position of relativistic images. In the weak-field regime, the
halo contributes already to the leading bending angle and enhances deviations from Kerr as $\rho$ grows. From the Einstein ring of ESO325-G004, we further obtain $0\leq\hat{\rho}\lesssim0.00939$ at $1\sigma$ and $0\leq\hat{\rho}\lesssim0.01963$ at $2\sigma$.
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All authors A. A. Araújo Filho, Arun Kumar, N. Heidari, C. F. S. Pereira, Amilcar R. Queiroz, V. B. Bezerra
Quantum Physics
Extracting conformal data from Loschmidt echoes after critical quenches
Aleix Bou-Comas, Stefano Carignano, Sergio Cerezo-Roquebrún et al. (+2 more)
Conformal field theory provides universal predictions for Loschmidt amplitudes following quenches from product states to critical
Hamiltonians. Building on this observation, we develop a route to extracting conformal data from real-time dynamics without preparing critical low-energy states. After analytic continuation, the Loschmidt amplitude is described by a boundary-CFT partition function on a strip, whose transverse transfer
matrix encodes both the boundary operator spectrum and the central charge. Local space-time perturbations of the amplitude are governed by
equilibrium correlation functions, and therefore provide access to critical exponents. In parallel, generalized temporal
entropies exhibit scaling with time analogous to the
equilibrium scaling of spatial
entanglement entropy. We show that the low-lying boundary spectrum can be reconstructed from the system-size dependence of finite-chain Loschmidt echoes, whose damped oscillations encode differences of boundary scaling dimensions. Finally, we propose a finite-size scaling protocol that can extract these quantities from simulations or experiments on state-of-the-art
quantum platforms.
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All authors Aleix Bou-Comas, Stefano Carignano, Sergio Cerezo-Roquebrún, Esperanza Lopez, Luca Tagliacozzo
Mesoscale and Nanoscale Physics
Valley Hall viscosity in the integer quantum Hall phases of (2+1)D Dirac materials
M. Selch
We calculate the valley-resolved
Hall viscosity for Lorentz-invariant integer
quantum Hall phases in Semenoff-semiconducting
graphene-like systems at zero temperature. The Kubo formalism based discussion reported in Phys. Rev. B 100, 115421 (2019) revealed the divergence of single valley viscous
Hall contributions for this case with only a valley-summed
Hall viscosity being finite and therefore well-defined. Our approach to the
Hall viscosity calculation is based on an equivalent Green function formulation within Wigner-Weyl calculus. We find that the previously identified divergence may be regularized in a way compatible with both valley-summed
Hall viscosity and (non)local
Hall conductivity. Together with the local
Hall conductivity and its first nonlocal correction, reported as well in Phys. Rev. B 100, 115421 (2019), we extend the empirical relativistic Hoyos-Son formula to individual valleys. Both the original Hoyos-Son formula for Galilean invariant fluids and its relativistic extension to Dirac materials are found to be structurally identical for integer
quantum Hall phases and expressible in terms of local electric and viscous
Hall responses. In addition we evaluate the valley(-difference)
Hall viscosity for biased Bernal
bilayer graphene in the
chiral fermion low energy approximation using the same regularization prescription. Prospects of measuring valley
Hall viscosity in nonlocal transport for mono- and
bilayer graphene- and group-VI TMD-based devices are discussed.
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Biological Physics
Acceleration-based clustering reveals frequent gait switching in sprint sled dogs
Benjamin Seleb and Saad Bhamla
Continuous
video is difficult to obtain during field studies of sprint sled dogs, limiting analysis of stride-to-stride variation during load-pulling gallop. We developed an acceleration-based pipeline to identify recurrent stride states from harness-mounted tri-axial accelerometers without manual gait labels. Using multivariate dynamic time warping,
manifold embedding, and density-based clustering, we analyzed more than 20,000 strides from a 10-dog team and identified recurrent, dog-specific stride states. In one previously annotated individual, acceleration-derived states were broadly consistent with manually labeled gallop patterns. Across dogs, transitions between stride states were frequent, with substantial inter-individual variation and limited evidence of strong team-level coordination. A simple logistic model based on local tugline-force timing and magnitude had weak predictive power for transition events. These results suggest that sprint sled dog gallop occupies a variable set of nearby stride states and that local tugline-force fluctuations alone do not explain the observed switching.
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Quantum Physics
Symmetry as a route to generalized bosonic Kitaev chains
Gideon Lee, Tony Jin and Aashish A. Clerk
The bosonic Kitaev chain (BKC) model is a deceptively simple looking quadratic pairing
Hamiltonian. Despite being purely Hermitian, it exhibits a number of striking non-Hermitian topological phenomena, including skin effects. We show here how
symmetries play a key role in this model, and how identifying these allows one to develop generalized BKC-like models. We emphasize the surprising fact that any quadratic bosonic pairing
Hamiltonian with a sublattice (
chiral)
symmetry necessarily has a dynamical
matrix with an effective time reversal
symmetry. This
symmetry is unrelated to physical time-reversal, but enables non-trivial topological invariants. We also discuss how this
symmetry is unrelated to another key property of the BKC, the decoupling of quadrature dynamics. This feature can instead be connected to a distinct
symmetry, namely an effective particle-hole
symmetry of the dynamical
matrix. We discuss non-trivial generalized BKC models that only keep one of these two effective
symmetries intact. We also provide a classification of all translationally-invariant 1D pairing
Hamiltonians, and show connections between the BKC and a well-studied non-Hermitian fermionic system, the
symplectic Hatano-Nelson model.
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