High Energy Physics (Theory)
The growth of $SO(9)$ super-representations in Type II string theory
Alessandro Georgoudis, Joseph A. Minahan, Gustav Ström et al. (+1 more)
We study the growth of massive $SO(9)$ super-representations in type II and type I string theories. We do this first directly by finding an empirical formula that specifies which representations appear at any level, and then compute the multiplicities from a refined partition function evaluated over finite fields up to level 501 for individual representations, and level 226 for all representations. We then derive asymptotic formulae for the growth of any representation, which are constructed by integrating about the peaks of the refined partition function. Using a Rademacher sum we can find very accurate approximations for the multiplicities of the representations. Unlike the superstring partition function, which only receives contributions from the odd Rademacher terms, the multiplicities for any representation have contributions from both even and odd terms. Finally, we apply the same techniques to the ordinary representations, where a simplified refined partition function allows for better computational speed and simpler expressions for the asymptotic approximations.
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All authors Alessandro Georgoudis, Joseph A. Minahan, Gustav Ström, Athanasios Zoumis
Atomic Physics
Sub-barrier peaks in atom-atom-ion three-body recombination
Fabian Thielemann, Joachim Siemund, Tobias Schaetz et al. (+1 more)
Hybrid atom-ion experiments have recently entered the few-partial wave regime in which magnetically tunable Feshbach resonances dominate the three-body loss dynamics. This necessitates a treatment of three-body recombination that can incorporate the role of the resonant dimer channel. Here, we develop a two-step Lindemann-type model for resonant atom-atom-ion three-body recombination that combines multichannel
quantum-defect theory for the long-range polarization potential with a universal
quantum-capture treatment of the inelastic atom-dimer step. We show that within our model, rate competition can lead to a peak in the three-body-recombination cross section of higher partial-wave channels at energies well below their corresponding centrifugal barrier. Investigating the resulting loss rates under numerically obtained non-thermal collision-energy distributions, we find that these effects survive the energy averaging and can be observed in state-of-the-art hybrid experimental setups. Our findings pave the way for a detailed characterization of atom-ion Feshbach resonances via the analysis of inelastic three-body-recombination processes.
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All authors Fabian Thielemann, Joachim Siemund, Tobias Schaetz, Krzysztof Jachymski
Quantum Physics
Gravitationally Induced Entanglement Across an Event Horizon
Hatim Salih
It has long been assumed that a particle–having crossed a black hole event horizon unentangled with another particle in the exterior universe–can no longer dynamically entangle with that particle. Here, we first establish the possibility of post-crossing
entanglement via an electromagnetic mediator. We then show within a gravitational time-delayed-potential model that
entanglement can be created between freely falling spatial superpositions across an event horizon. Radial escape, however, triggers bremsstrahlung emission–imposing a dephasing bound that grows with entangling phase, $\Gamma > \frac{6}{11\pi}\Phi$, within a constrained leading-quadrupole model–and is ultimately ruled out by macroscopic which-path leakage. By contrast, equivalent macroscopic optical masses in principle allow local harvesting of
entanglement tangentially, via
quantum erasure, thus revealing a remarkable
geometric duality: Spacetime irreversibly degrades
entanglement under radial escape, while allowing the transverse teleportation of the entangled
qubit to infinity, independent of Hawking evaporation.
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High Energy Physics (Theory)
SCFT/VOA correspondence and R-twisted reductions of $(A_2,D_{3n-2})$ Argyres–Douglas theories
Yutaka Yoshida
We study the SCFT/VOA correspondence for the $(A_2,D_{3n-2})$ Argyres–Douglas theories with $n\geq2$. From the matching of the central charges and the equality of the Schur index with the
vacuum supercharacter to all orders, we propose that the associated VOA is the logarithmic doublet
algebra $\mathcal A(4n-2)$ of Feigin, Feigin, and Tipunin. For $n=2$, this correspondence was studied in detail by Buican and Nishinaka, and our proposal extends it to $n\geq3$. Using the Nahm sum expression for the
vacuum supercharacter, we further propose a family of 3d $\mathcal N=2$ abelian Chern–Simons matter theories that flow to the 3d $\mathcal N=4$ SCFTs obtained by the R-twisted circle reduction, generalizing the $n=2$ construction. We determine the monopole superpotential and show that the Coulomb branch is $\mathbb C^2/\mathbb Z_2$ for every $n$. The superconformal index provides quantitative evidence for the proposed infrared fixed points, including the expected enhancement to $\mathcal N=4$ supersymmetry and the
Higgs and Coulomb branch structure.
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Mesoscale and Nanoscale Physics
Hydrodynamics of two-dimensional electrons due to scattering by disorder
D. R. Raskulov, K. A. Baryshnikov and P. S. Alekseev
The hydrodynamic regime of electron transport, induced by fast inter-electron collisions, was discovered in high-quality nanostructures in recent ten years. However, signs of hydrodynamic transport, primarily, the
giant negative magnetoresistance, were observed even at very low temperatures, when electron-electron scattering is too weak to affect the transport. To address this puzzle, here we develop a theory of mixed, hydrodynamic and non-Markovian, magnetotransport of two-dimensional electrons at zero temperature in samples with weak but still important disorder. Namely, we account for both the
memory effects at electron scattering by localized defects in
magnetic field and an unconventional viscosity effect due to electron scattering by defects in bulk and by rough sample edges. Solution of the model yields a strong negative magnetoresistance, which exhibits at zero
magnetic field a sharp maximum in narrower samples or a blunt maximum in wider samples. This and other our results explain various properties of the
giant negative magnetoresistance observed on ultra-high-quality GaAs
quantum wells, thereby we apparently reveal the nature of low-temperature magnetotransport in these systems.
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Mesoscale and Nanoscale Physics
Extrinsic orbital Edelstein effect from asymmetric scattering
Sankar Sarkar, Koushik Ghorai and Amit Agarwal
The generation and manipulation of orbital angular momentum (OAM) by an external electric field constitute one of the central themes of orbitronics. In particular, the electrically induced nonequilibrium OAM polarization, known as the orbital Edelstein effect (OEE), has attracted considerable
attention in recent years. While the intrinsic band-
geometric mechanism and the role of conventional symmetric
impurity scattering in the OEE are well understood, the contribution from disorder-induced asymmetric scattering remains unclear. Here, we develop a semiclassical theory that separates the OEE into intrinsic, Drude, side-jump, and third- and fourth-order skew-scattering channels. Unlike the Drude channel, the intrinsic, side-jump, and skew-scattering responses survive only in systems with broken time-reversal
symmetry. We find that in a magnetized Rashba two-dimensional electron gas (2DEG), these disorder-induced mechanisms can substantially exceed the intrinsic contribution. Remarkably, we find that for a system with Rashba coupling of $1$ $eV \AA$, the orbital magnetization is about one order of magnitude larger than the
spin magnetization for the chosen parameters, highlighting the crucial role of orbital degrees of freedom in the Edelstein effect.
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Statistical Mechanics
Effective Hamiltonian description on monitored Majorana chains: correlated power-law hoppings and unconventional entanglement scaling
Ken Mochizuki, Hisanori Oshima, Ryusuke Hamazaki et al. (+1 more)
We investigate the structure of effective
Hamiltonians governing monitored dynamics of a one-dimensional Majorana chain using Lyapunov spectral analysis. We focus on the gapless phase of the Lyapunov spectrum, where the effective
Hamiltonians behave differently from conventional critical
Hamiltonians in isolated systems; the spectral gap closes faster than $1/L$ but slower than $1/L^2$ and the
entanglement entropy grows as $[\ln(L)]^2$ where $L$ is the system size. We find that the effective
Hamiltonians have random long-range power-law hoppings with nontrivial magnitude correlations, rather than being independently and identically distributed. To elucidate the role of these non-Gaussian correlations, we construct random power-law hopping models that capture the essential features of the effective
Hamiltonians. The spectral gaps of the constructed models decay faster than $1/L$ but slower than $1/L^2$. We find that, in the absence of hopping correlations, the ground-state
entanglement exhibits $\ln(L)$ scaling. In the presence of correlations, by contrast, the
entanglement entropy is enhanced and its system-size dependence is consistent with $[\ln(L)]^2$ scaling over the system sizes studied. These results suggest that correlations among long-range hopping magnitudes are responsible for the
entanglement scaling rarely encountered in the ground states of conventional isolated
quantum systems.
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All authors Ken Mochizuki, Hisanori Oshima, Ryusuke Hamazaki, Yohei Fuji
Quantum Physics
Frequency-Multiplexed Parallel Gates for Quantum LDPC Codes in a Two-Dimensional Ion Crystal
G.-X. Tang, L.-M. Duan and Y.-K. Wu
Quantum low-density parity-check (qLDPC) codes admit high encoding rates but require nonlocal entangling gates for syndrome measurement. Instead of physically moving the
qubits which slows down with the increasing
qubit number, here we propose to achieve parallel nonlocal entangling gates on a two-dimensional (2D) ion
crystal using frequency-multiplexing. Adiabatic conditions ensure the suppression of gate infidelity and crosstalk error, as well as their robustness against slow drift in the trap frequency which is a leading error source in ion trap. We consider a numerical example of a $[[248,10,18]]$ bivariate bicycle code on a 2D
crystal of 512 ions. By optimizing the mapping of the
qubits and the assignment of the frequency bands for multiplexing, we show that a moderate
laser power is sufficient for parallelism, and that a logical error rate of $10^{-12}$ can be achieved under realistic noise parameters.
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Instrumentation and Detectors
Monitoring antiproton numbers with a CMOS detector in a dense-track environment
C. Regenfus, P. Adrich, I. Belosevic et al. (+42 more)
The production of antihydrogen by the GBAR experiment at AD/ELENA requires good knowledge of the number of incident keV antiprotons, which can be problematic. We have used a commercial CMOS digital camera mounted around the experimental
vacuum chamber to determine antiproton numbers from ionising particles created in the annihilation process on the surface of microchannel plate detectors which are used for beam imaging. We show that the multiplicity of emerging charged particles is as expected for individual annihilations of antiprotons with nucleons at rest, taking into account the surrounding material budget. Most of those particles are in the minimal ionising regime, but can be detected with nearly 100% efficiency in the CMOS pixel detector, while due to the thin depletion layer the device is insensitive to background gammas. Thanks to the high granularity and small pixel size millions of antiproton annihilations can be reconstructed in a dense tracking environment over a large dynamic range with good resolution. From cluster length studies of non perpendicular tracks the thickness of the depletion zone and effective detection area was estimated. The cluster length also allows for a monitoring of track angles. Antiproton numbers are determined from the number of reconstructed clusters in the CMOS sensor by means of the covered solid angle relative to a calibration measurements with well known beam intensities at the most upstream location of the GBAR apparatus. Material effects on the emerging annihilation products were estimated by Monte Carlo (Geant4) calculations, while annihilation artefacts on the complex surface of a microchannel plate are cancelled out in this approach. This method minimises largely systematic uncertainties, leading to a final error of roughly 10% for the reconstruction of absolute antiproton numbers.
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All authors C. Regenfus, P. Adrich, I. Belosevic, F. Benkel, M. Chung, P. Cladé, P. Comini, P. Crivelli, P. Debu, A. Douillet, S. Geffroy, S. Guellati-Khelifa, P. Guichard, P.-A. Hervieux, L. Hilico, P. Indelicato, S. Jonsell, J.-P. Karr, B. Kim, S. Kim, E.-S. Kim, N. Kuroda, B. Lee, L. Liszkay, D. Lunney, G. Manfredi, B. Mansoulié, V. Martimort, M. Matusiak, V. Nesvizhevsky, F. Nez, K. Park, N. Paul, E. Perez, P. Pérez, C. Roumegou, J.-Y. Roussé, F. Schmidt-Kaler, K. Szymczyk, T. A. Tanaka, B. Tuchming, D.-P. van der Werf, D. Won, S. Wronka, P. Yzombard
Astrophysics of Galaxies
Absolute Motion of the Infrared Counterpart to Sagittarius A* in the Gaia Celestial Reference Frame 3 and Limits on an Intermediate-mass Black Hole Companion
Rebecca A. Lewis-Merrill, Tuan Do, Matthew W. Hosek Jr. et al. (+9 more)
We report the first proper motion and acceleration measurements of the infrared (IR) counterpart to Sagittarius A* (Sgr A*-IR), the supermassive black hole (SMBH) at the center of our
Galaxy, in the
Gaia-Celestial Reference Frame (
Gaia-CRF3). This reference frame realizes the International Celestial Reference System (ICRS), which is an absolute reference coordinate system defined by
quasars. A combination of
Gaia and Hubble Space
Telescope data was used to transform Keck adaptive optics (AO) observations into
Gaia-CRF3. We developed a method for selecting reference
stars that minimizes astrometric transformation errors (statistical error = $0.10-0.63$ mas) and drift of the coordinate system (systematic error $\sim 0.01$ mas/yr). We find the proper motion of Sgr A*-IR in
Gaia-CRF3 to be $\mu_{\alpha^{*}} = -3.093 \pm 0.085$ mas yr$^{-1}$ and $\mu_{\delta}= -5.62 \pm 0.13$ mas yr$^{-1}$ with the initial position at $t_{0} = 2016.0$ of R.A. = 266.41680848 $\pm$ 0.00000029 deg and DEC = -29.00783947 $\pm$ 0.00000050 deg, which translates to a precision of 1.05 mas in R.A. and 1.79 mas DEC. This is consistent with the astrometric measurements of the
radio counterpart to Sgr A* by \citet{Xu_2022}. We also place a $2\sigma$ upper constraint of the acceleration of Sgr A*-IR on the sky at 0.061 mas yr$^{-2}$. This acceleration limit on Sgr A*-IR excludes any intermediate-mass black hole companion with mass $\gtrsim 4\times 10^{4}$ $M_{\odot}$ within a distance of $\sim$0.01 pc, consistent with previous studies. With the release of
Gaia Data Release 4, we predict these limits will be improved by at least a factor of two.
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All authors Rebecca A. Lewis-Merrill, Tuan Do, Matthew W. Hosek Jr., Gregory David Martinez, Shoko Sakai, Kelly Kosmo O'Neil, Grant Weldon, Abhimat Gautam, Zoë Haggard, Andrea M. Ghez, Jessica R. Lu, Keith Matthews
Quantum Physics
Algebraic Operator Decomposition: A Partitioned Architecture for Noise-Resilient Quantum Computing
Wladimir Silva
We present an operator-decomposition architecture that mathematically maps a global operator into independently executable local operators, reducing the maximum
quantum circuit depth at the cost of classical reconstruction and sampling overhead. By framing complex
Quantum Circuits around an operator in a vector space that can be algebraically pre-decomposed, AOD complements
quantum error correction and error-mitigation approaches by performing algebraic decomposition before
quantum execution. Our approach leans in the computer science definition of a Monoid: a design pattern and mathematical concept consisting of a data type, a combining function that is associative, and a safe identity (neutral) element that does not change other values when combined. Simulation wise we define a MapReduce programming model where the addition (+) is the reducer, thus leveraging a naturally stable commutative monoid which carries zero "negative-probability tax" or phase conflicts. Furthermore, we define a Vector Space of Linear Operators over Additive Abelian Groups that benefit from this paradigm, including: Inner Products, Series expansions, Traces and Convolutions. Finally, we present the mathematical foundations and simulation results for this paradigm.
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Materials Science
Synthesis and Characterization of Compositionally Complex (Gd/Ho/Er/Dy)2Zr2O7 Thin Film Combinatorial Library
Dalton A. Pearl, Jade Holliman Jr, Reece Emory et al. (+13 more)
High-throughput synthesis and characterization of novel ceramic materials with improved thermomechanical properties and phase stability are needed to accelerate the discovery of next-generation thermal barrier materials. A combinatorial thin film material library of (GdDyHoEr)2Zr2O7 were created via combinatorial magnetron reactive sputtering with rare-earth/zirconium
alloy targets. Structural, chemical, and thermal property characterization mapping across the four component composition space was performed and correlated with thermal transport measurements. Steady state thermoreflectance mapping identifies a pronounced minimum in thermal conductivity within the Dy/Gd-rich quadrant. This minimum does not coincide with either the equiatomic composition or the region predicted to exhibit maximum cation size disorder. Instead, it corresponds to the largest experimentally observed
lattice parameter, despite deviating from Vegard-like chemical averaging, and is independent of grain size and whole-pattern microstrain. These observations suggest that the way the fluorite
lattice accommodates compositional complexity, rather than cation size disorder alone, provides a more informative descriptor of thermal transport. Overall, this work establishes a high-throughput workflow for combinatorial thin-film synthesis and
multimodal characterization, enabling the rapid identification of previously inaccessible structure-property relationships in compositionally complex ceramics.
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All authors Dalton A. Pearl, Jade Holliman Jr, Reece Emory, Joshua Safin, Aditya Raghavan, Kamyar Barakati, Andrew H. Jones, Ethan A. Scott, Jack C. Lasseter, Adam Corrao, Daniel Olds, Bruce Ravel, Sergei K. Kalinin, Patrick E. Hopkins, Katharine Page, Philip D. Rack
Quantum Physics
Small-quench Loschmidt dynamics near quantum critical points
Kohei Kobayashi
We study the short-time Loschmidt dynamics after a small sudden quench near a
quantum critical point. We show that the initial quadratic growth of the Loschmidt rate function is governed by the variance of the quench operator per system size. For a local quench operator, this variance density is exactly equal to the spatial sum of the equal-time connected two-point correlation function in the initial ground state. This relation connects the early-time Loschmidt response to static critical correlations. Assuming power-law correlations at criticality, we classify the finite-size scaling of the short-time coefficient by the scaling dimension of the quench operator. In one dimension, the coefficient is finite, logarithmically enhanced, or algebraically enhanced with system size. We illustrate this operator dependence in the transverse-field Ising chain, where transverse-field and longitudinal-field quenches couple to different critical operators. We also discuss the first correction beyond the quadratic regime using the fourth cumulant of the post-quench
Hamiltonian.
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Quantum Physics
Quantum-Enhanced Phase Estimation with Photon-Added Even and Odd Coherent States in an SU(1,1) Interferometer
Abdelmajid El Maaroufi, Mouad Ait Maskour, Bouchra Maroufi et al. (+2 more)
We investigate phase estimation in an SU(1,1) interferometer employing $m$-
photon-added even and odd coherent states as nonclassical input resources. The phase sensitivity is evaluated through intensity detection and the error propagation method, while the ultimate precision limit is determined from the
quantum Cramér-Rao bound with the
quantum Fisher information serving as the relevant metrological quantity. Our results demonstrate that
photon addition significantly enhances the phase sensitivity, increases the
quantum Fisher information, and reduces the
quantum Cramér-Rao bound, leading to a clear improvement over the corresponding even and odd coherent states. Furthermore, the achievable sensitivity exceeds the standard
quantum limit and gradually approaches the Heisenberg scaling with increasing
photon-addition number. We also find that the $m$-
photon-added even coherent states exhibit a modest advantage over their odd counterparts. As $m$ increases, however, this distinction becomes progressively weaker, suggesting that
photon addition diminishes the role of the initial parity of the coherent state in determining the interferometric performance.
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All authors Abdelmajid El Maaroufi, Mouad Ait Maskour, Bouchra Maroufi, Mohammed Daoud, Saeed Haddadi
Soft Condensed Matter
Topological Mixing and Braiding Universality in Polar Active Matter
Wei Feng, Tianyu Ren, Zhihan Ye et al. (+2 more)
Connecting the autonomous kinematics of active matter to its emergent macroscopic transport is constrained by the requirement for high-resolution Eulerian velocity fields. Here, we use confined bacterial suspensions as a model active fluid, mapping the sparse Lagrangian trajectories of fluorescent spy
cells into (2+1)-dimensional
geometric braids that directly encode the spatiotemporal
entanglement of the flow. We use the finite-time braiding exponent (FTBE) as a proxy to quantify the topological
entropy and chaotic mixing of confined bacterial suspensions. In moderately confined wet systems, we find that hydrodynamic coupling drives a structural transition from a dilute active gas to coherent
vortices, and ultimately to active
turbulence, revealing three distinct density-dependent regimes of topological mixing. Conversely, truncating the hydrodynamic screening length via extreme confinement drives the system toward a dry active matter limit. In this limit, dense in-plane steric collisions suppress irreducible
entanglement and substantially reduce the FTBE at high particle densities. By evaluating the topological complexity generated per encounter, we reveal a transition from a discrete
geometric encounter regime to an areal escape mechanism. Finally, we establish a square-root scaling between the FTBE and the effective diffusivity, placing the self-sustained mixing of active fluids into the pathline braiding universality class.
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All authors Wei Feng, Tianyu Ren, Zhihan Ye, Jonas Berx, Guangyin Jing
Mathematical Physics
A simple derivation of the zero-temperature BCS functional from the reduced BCS Hamiltonian
Christian Hainzl and Riccardo Panza
We consider a grand-canonical reduced BCS
Hamiltonian on the full fermionic Fock space with an attractive pairing interaction supported in an energy shell around the
Fermi surface. For fixed chemical potential, we prove that the exact finite-volume ground-state energy differs from the minimum of the corresponding finite-volume BCS functional by a volume-independent error. As a consequence, the BCS variational principle is exact for the ground-state energy density in the thermodynamic limit.
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Mathematical Physics
Limits of Stochastic Semigroups and Block-Triangular Majorisation
Fabio Deelan Cunden, Jakub Czartowski, Giovanni Gramegna et al. (+1 more)
We investigate limits of
semigroups of
stochastic matrices defined by their invariant distribution. Given probability vectors $\gamma(\beta)$ depending on a parameter $\beta$, we introduce a notion of convergence as $\beta\to\infty$ for the corresponding
semigroups of $\gamma(\beta)$-preserving
stochastic matrices and investigate the structure of the resulting limit. In general, the limiting
semigroup differs from the
semigroup preserving the limiting distribution, showing that these two operations do not commute. We develop a general framework for such limiting
semigroups and study in detail the case in which the invariant distributions are Gibbs vectors at the inverse temperature $\beta$. We show that the limiting
semigroup consists of block-upper-triangular
stochastic matrices subject to additional substochasticity constraints. We characterise and enumerate their extremal elements and determine the preorder on probability vectors induced by the action of the
semigroup. The resulting notion of Block-Triangular majorisation interpolates between ordinary majorisation and upper triangular (aka unordered) majorisation. We show that it is completely characterised by a finite family of monotones and analyse the corresponding behaviour of Rényi $\alpha$-
entropies as $\beta\to\infty$.
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All authors Fabio Deelan Cunden, Jakub Czartowski, Giovanni Gramegna, Marilena Ligabò
General Relativity and Quantum Cosmology
An off-shell conformally invariant Galilean Weyl tensor
Quentin Vigneron, Philip K. Schwartz and James Read
We propose a manifestly conformally invariant off-shell definition of the Weyl tensor in Galilean geometry. We also propose definitions for the electric and
magnetic parts thereof. For the latter to vanish, observers with specific kinematical properties need to exist. While this is guaranteed by the Newton–Cartan equation, it might not be true for other Galilean invariant theories. Therefore, we propose that imposing the existence of observers for which the off-shell
magnetic part is zero should be a necessary condition for a Galilean invariant theory to be called `Newtonian', in the spirit of the `Newtonian' condition, introduced by Trautman, in standard Newton–Cartan
gravity. As a side result, we also show that there exists a unique Galilean boost-invariant connection that can be built from a Galilean structure and a choice of Coriolis field, even when the clock form is not closed. No extra structure is needed, contrasting with the standard approach used to construct boost-invariant connections which introduces a mass gauge field.
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High Energy Astrophysical Phenomena
Sgr A* as a Galactic PeVatron: Multimessenger Signatures of the Magnetic Penrose Process
Marina Cermeño, Pedro De la Torre Luque, Cristina Fernández-Suárez et al. (+5 more)
The
magnetic Penrose process (MPP) is one of the most efficient mechanisms for extracting rotational energy from a magnetized Kerr black hole (BH), enabling charged particles to reach very-high energies. We investigate this process in Sagittarius A* (Sgr A*), the supermassive BH at the
Galactic center (GC), focusing on its ultra-high-efficiency regime, in which
neutrons undergo beta decay inside the BH ergosphere. As a key novelty, we compute the
neutron production spectrum in the
accretion flow directly from the
nuclear reaction kinematics and follow
neutron trajectories in the Kerr spacetime to determine the population that reaches the ergosphere and undergoes the MPP. From this population, we derive the spectrum of accelerated
protons and show that Sgr A* can accelerate them up to PeV energies, strengthening its interpretation as a candidate
Galactic PeVatron. We further compute the gamma-ray and
neutrino emission produced through hadronic interactions of the escaping
protons in the Central Molecular Zone. The predicted gamma-ray fluxes exhibit distinctive spectral features that could provide an observational signature of the MPP and may constitute a non-negligible contribution to the very-high-energy emission detected by H.E.S.S. and HAWC. The associated
neutrino fluxes remain below the diffuse
Galactic component inferred by IceCube, but may still contribute to the high-energy emission from the GC. Remarkably, the predicted signals lie within the projected sensitivity of SWGO for all scenarios considered here and, for some models, only a factor of a few below the nominal CTAO sensitivity, while KM3NeT/ARCA and IceCube-Gen2 will provide complementary tests. Our results establish the MPP as an observable mechanism for extracting BH rotational energy, providing a direct connection between horizon-scale physics and multimessenger observations that can be extended to other magnetized BHs.
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All authors Marina Cermeño, Pedro De la Torre Luque, Cristina Fernández-Suárez, Viviana Gammaldi, Enrique Mier-Alonso, María J. Rodríguez, Miguel Á. Sánchez-Conde, Jaume Zuriaga-Puig
High Energy Physics (Phenomenology)
TQ4Q2.0 Fragmentation Functions for Fully Heavy Tetraquark Production
Francesco Giovanni Celiberto
We investigate the fragmentation dynamics underlying the production of fully heavy tetraquarks by means of the TQ4Q2.0 collinear FF set, covering scalar ($0^{++}$), axial-vector ($1^{+-}$), and tensor ($2^{++}$) configurations. The fragmentation inputs are determined within NRQCD factorization for the complete set of relevant partonic channels and are subsequently evolved across heavy-
flavor thresholds through the HF-NRevo scheme. Perturbative uncertainties associated with fragmentation-scale variations are consistently propagated together with nonperturbative effects encoded in color-composite long-distance
matrix elements.
Attention is devoted to the axial-vector sector, whose fragmentation pattern makes it especially sensitive to intrinsic-charm contributions at LHC and FCC energies. TQ4Q2.0 therefore provides an uncertainty-aware framework for exploring fully heavy tetraquark production over a broad kinematic range and for connecting exotic-
hadron spectroscopy with the partonic structure of the
proton.
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Nuclear Theory
Microscopic Calculation of Electric Quadrupole Effective Charges in Exotic Nuclei
Jia Liu, Yong Peng, Xiao-Yan Zhu et al. (+4 more)
Electric quadrupole ($E2$) effective charges are evaluated based on the self-consistent relativistic Hartree-Fock single-particle states, with core-polarization corrections resummed to all orders using the Tamm-Dancoff approximation (TDA). Configuration-interaction relativistic Hartree-Fock (CI-RHF) calculations employing the TDA effective charges well reproduce the $B(E2)$ strength for neon isotopes from stability to the
neutron drip line. We find that polarization charges associated with continuum states are significantly quenched due to their extended density distributions and weak coupling to the core, underscoring the critical role of continuum effects in $E2$ transition evaluations for exotic
nuclei. Moreover, the CI-RHF model predicts a suppressed $B(E2; 2^+_2 \to 0^+_2)$ in $^{30}$Ne, together with strong in-band $B(E2)$ strengths of the yrast band, suggesting the coexistence of a nearly spherical excited $0^+_2$ state and a deformed ground state within the $N=20$ "island of inversion".
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All authors Jia Liu, Yong Peng, Xiao-Yan Zhu, Xiao-Hua Li, Wen Luo, Yi-Fei Niu, Wen-Hui Long
Instrumentation and Detectors
Testbeam characterization of a 3D silicon sensor read out by Timepix4
E. Chatzianagnostou, M. J. Madurai, K. Akiba et al. (+15 more)
Testbeam results from a $300\,\mu\mathrm{m}$-thick 3D silicon sensor bump-bonded to a Timepix4 ASIC, are presented. The hit detection efficiency, spatial resolution, and timing performance of the 3D sensor are studied for several track angles, bias voltages and charge thresholds. The time measurements are corrected for Timepix4 clock-frequency variations and timewalk, while for the spatial studies, nonlinear charge-sharing corrections are determined. At perpendicular incidence, the time resolution of the 3D detector is equal to $245\,\mathrm{ps}$ with a $97\%$ hit detection efficiency. An optimal angle of $8^\circ$ with respect to the beam direction of the 3D detector was found, in which the time resolution improves by $6\%$ compared to normal incidence, while the hit detection efficiency reaches above $99\%$ and the spatial resolution is approximately $7\,\mu\mathrm{m}$. Intrapixel studies show that a time resolution of $153\,\mathrm{ps}$ at the most probable value of the signal charge can be achieved for hits between the electrodes at normal incidence, while the timing performance of these best-performing regions deteriorate upon sensor rotation. The timing properties at different depths of the 3D sensor have been investigated with tracks at grazing-angle incidence, revealing a dependence of the time resolution along the sensor depth.
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All authors E. Chatzianagnostou, M. J. Madurai, K. Akiba, D. Bacher, R. Bates, M. van Beuzekom, T. Bischoff, V. Coco, R. Dumps, T. Evans, K. Heijhoff, D. Johnson, U. Krämer, E. Lemos Cid, D. Oppenhuis, T. Pajero, E. Rodríguez Rodríguez, D. Rolf
High Energy Physics (Theory)
Cutting corners: exciting and magical bounds from the cusp bootstrap
Ryan A. Lanzetta, Ian Moult and Yifan Wang
An illuminating probe of the dynamics of a line defect is the global geometry of its worldline. For a conformal line defect in a conformal field theory, sharp corners in the worldline, i.e. cusps, host dynamical degrees of freedom characterized in part by a spectrum of scaling dimensions, called cusp anomalous dimensions. We present various general bounds on cusp anomalous dimensions following from unitarity and cutting-and-gluing consistency of different defect geometries. We first establish, for cusps involving conjugate defects, that level crossings upon varying the cusp angle are forbidden between the lightest singlet cusp and any non-singlet cusp, proving that singlet cusps are the lightest. Then, we study line defects arranged in a rectangular geometry, which are subject to bootstrap constraints reminiscent of the spinless modular bootstrap. We find an analytic “magic" functional that produces an optimal and universal lower bound on the dimension of a right angle bare cusp in terms of the universal defect Casimir energy between the corresponding defect and its conjugate in flat space.
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High Energy Physics (Phenomenology)
Exploring Extended Higgs Dynamics via Higgsstrahlung at FCC-ee
Anisha, Francisco Arco, Stefano Di Noi et al. (+2 more)
The Future Circular Electron-Positron
Collider (FCC-ee) will probe aspects of the
Higgs boson and the electroweak scale with unprecedented precision via associated
Higgs production with a $Z$
boson. We focus on the Two-
Higgs-Doublet Model (2HDM) to frame the FCC-ee's precision constraints within a small, concrete parameter space at next-to-leading order. We demonstrate that the projected precision of the FCC-ee's 240 GeV run will enable a precise analysis of Beyond-the-Standard-Model (BSM)-relevant
Higgs-sector interactions near the
alignment limit. As the key aspects of the 2HDM that drive deviations of the cross section from its Standard Model expectation (presence of new scalar states,
Higgs mixing, and non-trivial inter-
Higgs couplings) are also typically present in extensions more complex than the 2HDM, this demonstrates the FCC-ee's indirect potential for unveiling BSM physics around the electroweak scale.
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All authors Anisha, Francisco Arco, Stefano Di Noi, Christoph Englert, Margarete Mühlleitner
Quantum Physics
Discrete time crystals in disordered anisotropic Heisenberg chains
Francesco Formicola, Grazia Di Bello, Antonio De Candia et al. (+2 more)
A discrete time
crystal is an out-of-
equilibrium phase of matter characterized by the spontaneous breaking of discrete time-translation
symmetry. Using extensive numerical simulations based on
matrix-product-state methods, we provide evidence for discrete time-crystalline behavior in strongly disordered
spin chains with Heisenberg interactions, including the isotropic point, subject to periodic driving. Starting from a many-body localized regime, we observe that rotations induced by delta kicks produce a pronounced subharmonic response at half the drive frequency in
spin observables. We investigate the stability of this response against rotation-angle errors through
entanglement entropy,
quantum Fisher information, short-range
spin correlations, and restricted-control ergotropy. Increasing the rotation error reveals an intermediate dynamical regime separating the time-crystalline and Floquet-localized responses. In this regime, most observables exhibit signatures of weakly correlated dynamics reminiscent of Anderson localization.
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All authors Francesco Formicola, Grazia Di Bello, Antonio De Candia, Giulio De Filippis, Carmine Antonio Perroni
Solar and Stellar Astrophysics
Ionized Nebulae Around Two New Symbiotic Stars: GR Cygni and [D75] 141
Howard E. Bond, Calvin Carter, Sven E. Eklund et al. (+4 more)
In the course of selecting targets for a spectroscopic survey of faint planetary-nebula
nuclei, we encountered two anomalous cases of late-type variable
stars surrounded by nebulosities discovered by amateur astronomers. We obtained follow-up deep narrow-band images of the two nebulae: StDr Objet 14 (diameter 1.5 arcmin) and StDr 4 (diameter 2.5 arcmin). StDr Objet 14 is found to be a low-excitation nebula, bright only in Ha+[N II], and showing a unique double-ring "bull's-eye" morphology. StDr 4 exhibits a bow-shock structure, bright in Halpha and [S II], embedded in an extended emission nebula. Both central
stars, respectively GR Cygni and [D75] 141, are found to be pulsating semiregular variable
stars. Our spectroscopic observations show GR Cyg to be a cool carbon
star of type C9,2, with emission lines of the Balmer series, [O II] and [O III], [Ne III], [S II], and Fe II. A synthetic narrow-band image of GR Cyg shows that the source of its strong [O II] 3727 A emission line is a
knot displaced from the
star by about 1.6 arcsec, indicative of a recent collimated ejection event. [D75] 141 is a M6 III red
giant, with weak Balmer-series emission. Both
stars show a blue excess, and GR Cyg was detected in the near-UV by the GALEX spacecraft. These data establish both
stars as new symbiotic binaries, containing a late-type red
giant and a hot companion accreting from its
stellar wind. We speculate that the double rings surrounding GR Cyg were ejected during helium-shell thermal pulses (or conceivably from recurring nova outbursts), while the nebula around [D75] 141 may be the result of a collision of the symbiotic
star's ejecta with an interstellar cloud. Our accidental discoveries of these two binaries because they are surrounded by faint nebulae supports the view that there is a significant population of "missing" symbiotic
stars yet to be discovered.
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All authors Howard E. Bond, Calvin Carter, Sven E. Eklund, Peter Goodhew, Ulisse Munari, Jonathan Talbot, Gregory R. Zeimann
High Energy Physics (Theory)
Cusped Defects: Cusp Operator Expansion, Conformal Properties and Bootstrap Applications
Lorenzo Bianchi, Andrea Cavaglià, A. David Gutiérrez et al. (+2 more)
We analyze general properties of cusped defect lines embedded in generic conformal field theories (CFTs). We prove that suitably defined cusp scaling operators transform like primary operators under general conformal transformations. We show that, via the cusp operator expansion (COE), defects of general shape can be expanded in a basis of cusped defects. These findings are checked and exemplified in the case of the localized
magnetic field defect. Finally, we derive analytic constraints on dynamical cusp data by making use of a crossing equation, and discuss possible numerical bootstrap applications of our results.
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All authors Lorenzo Bianchi, Andrea Cavaglià, A. David Gutiérrez, Stefanos R. Kousvos, Marco Meineri
Soft Condensed Matter
Mechanistic Framework for Multicomponent Nanoparticle Assembly: Predicting RNA-lipid and PEI-DNA nanoparticle assembly
Turash Haque Pial and Tine Curk
The assembly of multicomponent nanoparticles is often kinetically controlled and exhibits strong pathway dependence. Transport, solvent exchange, nucleation/growth, and collision-driven coalescence together determine not only ensemble-averaged properties but also particle-to-particle compositional heterogeneity. Here, we present a computational modeling framework for predicting nanoparticle property distributions by coupling processing conditions, early-stage self-assembly physics, and molecular chemical details with kinetic Monte Carlo (kMC) simulations. The framework combines (i) mixing conditions with solvent-exchange-mediated particle initialization and growth, and (ii) kMC simulations that resolve
stochastic collision histories, electrostatics-controlled coalescence, and composition at the level of individual particles. Applied to mRNA lipid nanoparticles, the model predicts size-loading correlations and provides insight into how processing-dependent assembly pathways lead to heterogeneous payload distributions. The kMC simulations further provide merging lineage histories, which explain the emergence of log-normal volume and payload distributions through multiplicative particle-growth pathways. The same framework is also applied to PEI-DNA polyelectrolytic complexation, yielding single-particle-resolved DNA-PEI stoichiometry distributions. The framework and its open-source implementation, FormLNP, provide a process-aware route to predicting and controlling single-particle property distributions across a broad range of multicomponent nanoparticle systems.
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Optics
Accounting for the detection response brings cavity ring-down spectroscopy to sub-permille accuracy
Rajesh Chell, Marcin Gibas, Szymon Wójtewicz et al. (+3 more)
For nearly four decades, cavity ring-down spectroscopy (CRDS) has been among the simplest, most widely used absorption techniques, requiring no calibration because it measures decay times, not intensities. Yet as accuracy requirements have tightened, CRDS has proven strikingly inconsistent: reported errors range from several percent to the permille level - the signature of an uncontrolled systematic effect so far worked around rather than resolved. This has confined applications demanding the highest accuracy - from testing ab initio theory to atmospheric sensing and
quantum-based metrology - to a handful of laboratories relying on advanced calibration or architectures, at the cost of simplicity. Here we show the main source was hiding in plain sight: the detection chain's transient response. It distorts every ring-down, biasing the retrieved decay times differently from instrument to instrument - a bias that routine truncation of the early decay masks rather than removes. We measure this response with a calibration-free beat-note method and build it into the ring-down model. Validation uses a well-characterized carbon monoxide transition and an independent frequency-based reference. Across four detection configurations, line-intensity biases of up to 14 % shrink 41- to 87-fold, the results converge, reaching up to sub-permille agreement with the reference. This holds down to 4 us ring-down times, extending accurate CRDS to stronger absorption. Independent of the absorbing species and requiring no change to the CRDS setup, the approach turns a technique valued for its simplicity into one equally valued for its accuracy.
Benchmark-quality measurement thus comes within reach of any CRDS laboratory.
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All authors Rajesh Chell, Marcin Gibas, Szymon Wójtewicz, Jakub Łasocha, Daniel Lisak, Agata Cygan
Quantum Physics
Robust multi-hypothesis quantum-state discrimination under unknown common unitary perturbations via least favorable priors
Daichi Fujiki and Fuyuhiko Tanaka
We study robust K-ary
quantum-state discrimination when all candidate states are affected by the same unknown common
unitary perturbation. The unknown perturbation does not represent the label to be identified, but acts as a nuisance factor that changes the performance of a fixed measurement. We formulate the problem as a minimax decision problem over the possible perturbations and propose using the Bayes-optimal collective measurement associated with a least favorable prior (LFP) on the nuisance-parameter space. For a finite discretization of this space, we show that the LFP can be computed by a semidefinite program and that the corresponding value coincides with the finite-grid minimax success probability. As numerical demonstrations, we consider a binary nonorthogonal
qubit model and a nonorthogonal three-state qutrit model with an unknown common
unitary perturbation. The LFP-based measurement substantially flattens the success-probability profile and improves the worst-case success probability compared with a reference-point optimal measurement and a uniform-prior Bayes measurement. The resulting LFP concentrates its weight on regions of the nuisance-parameter space that actively limit the robust discrimination performance, thereby providing both a constructive measurement design and a diagnostic description of the difficult nuisance-parameter regimes.
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