Cosmology and Nongalactic Astrophysics
Bounding the Effect of HOD Assumptions on Small-Scale Clustering Constraints
Nick Magnelli, Zachery Brown and Lado Samushia
Small-scale
galaxy clustering is expected to contain substantial cosmological information, but the extent to which this information constrains
halo-based cosmologies independent of an assumed
galaxy–
halo connection remains unclear. We quantify this dependence using LRG-like mock
galaxy catalogs built from 81 cosmologies in the {\tt AbacusSummit} suite. We analyze two-point correlation function multipoles on scales ranging from $5$–$80$ Mpc/$h$ and compare two limiting treatments, the \enquote{floor} and \enquote{ceiling}, of the standard five-parameter HOD model. In the conservative floor case, we impose only broad initial HOD bounds and profile over HOD parameters to determine the minimum constraining power available; we accomplish this with HODmin, a two-stage global optimization
algorithm written for minimizing $\chi^2$ in HOD space. In the optimistic ceiling case, we assume the HOD parameters are known exactly. We find a significant difference between the floor and ceiling when comparing against the same Planck $\Lambda$CDM mock data vector with identical modeling assumptions: for the floor, $25\%$ of the discrete {\tt AbacusSummit} cosmologies tested are excluded at $3\sigma$, whereas for the ceiling, $\sim81\%$ are excluded. Many cosmologies agree well with data in the floor, and yet in the ceiling are excluded by multiple orders of magnitude in $\chi^2$. We therefore observe the strength of small-scale clustering constraints depends heavily on the amount of prior HOD information assumed. We compare the sensitivity of this effect to various choices like scale cut, angle cut, multipole inclusion, mock phase, and mock HOD model. Our wide floor–ceiling bracket indicates that informative
galaxy–
halo priors are necessary for extracting strong small-scale clustering constraints.
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High Energy Physics (Phenomenology)
Collective neutrino oscillations: Many-body non-forward effects and non-classicality
Julien Froustey, Ermal Rrapaj, Yuhao Liu et al. (+3 more)
Neutrino evolution in dense astrophysical environments is typically described either within a
quantum kinetic framework, which neglects the build-up of multi-body correlations, or through simplified many-body calculations that allow significant
entanglement to develop. In this work, we compare these two approaches in a simple
neutrino-gas configuration, with particular emphasis on the role of non-forward scattering processes. These effects are incorporated either through a collision term in the kinetic description, or by considering the full
neutrino-
neutrino many-body
Hamiltonian. We highlight differences between the two descriptions in both their characteristic timescales and asymptotic behavior. Motivated by the natural suitability of
quantum computing for many-body calculations, we further investigate the non-classicality of
neutrino evolution, discussing Trotter error scaling, along with the associated costs of constructing
quantum circuits in terms of entangling gates and non-Clifford gates. We find that the resources needed for
neutrino many-body
evolution are on the low end of typical high-energy physics problems and on the mid to high end with respect to
quantum chemistry problems. For the full
Hamiltonian, resource requirements increase relative to the truncated version. We emphasize the importance of efficient
fermion-to-
qubit encodings, which are essential for reducing the substantial computational resources required for such simulations.
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All authors Julien Froustey, Ermal Rrapaj, Yuhao Liu, Gushu Li, Costin Iancu, Vincenzo Cirigliano
Earth and Planetary Astrophysics
The carbon isotope ratio of \beta\ Pic b with high-resolution spectroscopy
D. González Picos, I.A.G. Snellen, R. Landman et al. (+6 more)
Isotopic ratios trace the formation and
evolution of
planets and link their atmospheres to the chemistry of their natal protoplanetary discs. We measure $^{12}\mathrm{C}/^{13}\mathrm{C} = 58^{+18}_{-15}$ in the atmosphere of the young super-Jupiter $\beta$ Pic b from 11 nights of CRIRES+ K-band spectroscopy ($\mathcal{R} \approx 100{,}000$) at the Very Large
Telescope (VLT). We detect both $^{12}\mathrm{CO}$ and $^{13}\mathrm{CO}$ and constrain $^{12}\mathrm{C}/^{13}\mathrm{C}$ with a
Bayesian retrieval jointly fitted with near-infrared photometry. The inferred $^{12}\mathrm{C}/^{13}\mathrm{C}$ is consistent with the present-day interstellar medium (ISM), is below the
solar value, and is comparable to measurements in other young super-Jupiters. We also retrieve $T_{\rm eff} = 1629^{+30}_{-28}\,\mathrm{K}$, near-
solar to mildly super-
solar metallicity ([M/H]$ = 0.20^{+0.16}_{-0.12}$), a
solar-like carbon-to-oxygen ratio (C/O$ = 0.52 \pm 0.03$), and tentative evidence for thick clouds. We analyse each night independently and combine the results of the six epochs with the highest signal-to-noise ratio (S/N), propagating night-to-night scatter into the final uncertainties. This provides an isotopic
benchmark for a directly imaged
planet interior to the CO snow line.
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All authors D. González Picos, I.A.G. Snellen, R. Landman, S. de Regt, N. Grasser, J. L. Birkby, T. Stolker, I. Koutalios, M.A. Kenworthy
Physics and Society
Revealing Peri-Urban Dislocation through Percolation Analysis
Dr Melissa Barrientos-Trinanes, Professor Stephen Marshall and Professor Elsa Arcaute
This paper introduces peri urban dislocation as a structural condition that complements existing sprawl metrics by capturing hierarchical misalignments between inner city and peripheral areas. Whereas conventional measures emphasise density, land-use mix, or fragmentation, peri-urban dislocation reflects deeper divergences in the core periphery relational functional organisation of urban systems. We operationalise this concept using percolation analysis of street networks, revealing hierarchical patterns via clustering maps and dendrograms, providing a relational structure between urban elements. Two case studies, Valdivia, Chile, and Boston, USA, demonstrate contrasting manifestations: a structural reversal in Valdivia, where a homogeneous residential periphery dominates the hierarchical clustering process, and peri-urban voids in Boston, where isolated parcellations persist despite metropolitan consolidation. These findings position peri-urban dislocation as a structural dimension linked to sprawl yet distinct from metrics based on density or peripherality; one that may occur independently or represent a previously unidentified structural signature of sprawl. Methodologically, we apply established percolation techniques to expose this previously unarticulated structural phenomenon, enabling the detection of hierarchical misalignments within urban systems. Conceptually, we introduce peri urban dislocation as a new dimension of urban structure, helping articulate debates on sprawl and peri urbanisation through a complexity informed lens and enabling core periphery diagnostics across diverse urban contexts.
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Optics
Quantifying the Distribution of Biexciton Emission Efficiencies in Colloidal Quantum Shells
Tjom Arens, Dulanjan Harankahage, Divesh Nazar et al. (+2 more)
The efficiency of multi-
photon emission is an important characteristic of
quantum light sources. Bright multi-
photon emission is desirable for high-power lighting and
lasers, while its complete suppression is required for high-purity single-
photon generation. In colloidal
quantum emitters, multi-
photon emission can vary significantly between individual particles. Resolving this heterogeneity remains challenging with conventional particle-by-particle approaches. Here, we introduce a crosstalk-suppressed SPAD-array
photon-correlation approach for high-throughput quantification of multi-
photon emission from more than 1000 colloidal
quantum shells. By projecting two images of the same sample onto distant regions of the detector array, we avoid short-range crosstalk between detector pixels. Time gating suppresses dark-count coincidences and distinguishes individual emitters from clusters. Applying this method to
quantum shells reveals a near-Gaussian distribution of biexciton emission efficiencies, with a mean of 0.55 and an estimated intrinsic standard deviation of 0.12. Intra-batch correlations between the biexciton efficiency and the particle brightness are consistent with the volume scaling of Auger quenching. These results establish SPAD-array
photon correlation as a scalable route to resolve multi-
photon heterogeneities in nanoparticle ensembles.
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All authors Tjom Arens, Dulanjan Harankahage, Divesh Nazar, Mikhail Zamkov, Freddy T. Rabouw
Quantum Physics
Scaling-optimal purification of noisy qubit unitary channels
Ryotaro Niwa, Satoshi Yoshida, Koki Ono et al. (+5 more)
We consider the problem of purifying noisy
qubit unitary channels. Given the ability to apply an unknown
qubit unitary channel followed by depolarizing noise, we aim to construct a superchannel that purifies the noisy
unitary back to the original unknown
unitary. We first provide numerical evidence that sequential strategies can strictly outperform parallel strategies when the number of channel uses is finite, highlighting the fundamental distinction from state purification. We then provide a concrete $\mathrm{U}(2)$-covariant parallel protocol based on a novel
entanglement-assisted
quantum error-correcting code that suppresses the first-order noise strength as $O(1/n)$ with $n$ channel uses and show this scaling is asymptotically optimal in the low-noise regime, even when sequential strategies are allowed.
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All authors Ryotaro Niwa, Satoshi Yoshida, Koki Ono, Takeru Utsumi, Zhaoyi Li, Yuxiang Yang, Ryuji Takagi, Mio Murao
High Energy Physics (Phenomenology)
The Fundaments of Unity: ${\mathcal O}(1)$ Couplings in Quantum Field Theories
Ben Allanach
We critically examine the expectation that in a fundamental
quantum field theory, dimensionless couplings in the Lagrangian density should all be of order unity. We propose a measure to quantify the adherence of a theory to this: the spread (the ratio of the largest to the smallest of the magnitudes) of such dimensionless couplings, obtaining various closed-form results. If we take independent and identically distributed (IID) couplings to parameterise our uncertainty on the values of the order-unity couplings, the spread can be much larger than one might naively expect. For a theory with 20 IID unit normal couplings, the probability that the spread is greater than 100 is 0.29, for example. Even when the IID couplings have exponentially suppressed tails, the distribution of the spread has fat power-law tails whose amplitude grows with the number of independent couplings.
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Plasma Physics
Secondary drift-driven instabilities in the presence of a parallel-propagating electromagnetic ion cyclotron wave and cold multi-component ions
Opal Issan, Patrick Kilian, Vadim Roytershteyn et al. (+2 more)
Electromagnetic ion cyclotron (EMIC) waves are commonly observed in Earth's inner magnetosphere, particularly during geomagnetic storms driven by anisotropic ring-current
protons. While their role in radiation belt scattering of hot ions is well established, their interaction with the cold (less than 100 eV)
plasma remains less understood. This is partly due to limited magnetospheric cold ion observations, as spacecraft charging can prevent cold ions from reaching onboard instruments. It is well-known that the electric field of a parallel-propagating EMIC wave can drive inter-species perpendicular polarization drifts that excite lower-hybrid secondary instabilities. In multi-component
plasmas, these include the modified two-stream and the ion-ion cross-field instabilities. In this paper, we study the impact of such secondary instabilities on the parallel-propagating EMIC wave and multi-component
plasma via a fully kinetic particle-in-
cell simulation and linear theory. We find that the secondary waves persist even at low EMIC amplitudes, provided the cold population remains sufficiently cold. The kinetic simulation demonstrates that these secondary modes produce anisotropic heating of cold
protons and singly-charged oxygen ions, primarily in the direction perpendicular to the ambient
magnetic field and of electrons in both parallel and perpendicular directions.
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All authors Opal Issan, Patrick Kilian, Vadim Roytershteyn, Salomon Janhunen, Gian Luca Delzanno
High Energy Astrophysical Phenomena
Time-dependent cosmic-ray escape from wind bubbles: hard spectra formation
Lukas Merten, Sophie Aerdker and Enrico Peretti
Overview: Wind-driven bubbles are dynamic systems that can accelerate
cosmic rays, depending on their physical properties, up to very high energies. We investigate how a time-dependent description of the particle transport may impact the escaping
cosmic-ray flux. Model: The wind bubble system is modeled as spherically symmetric.
Cosmic rays are continuously injected at the position of the termination shock and propagate through advection and
diffusion until the escape at the time-dependent position of the forward shock, which is treated as a free escape boundary. Methods: The one-dimensional spherical time-dependent transport equation is solved by transforming it into the corresponding set of
stochastic differential equations, and integrated with a modified version of the open source
cosmic-ray propagation framework CRPropa. Results: We find that, during the wind driven phase, the downstream escaping spectra from wind bubbles can be harder than $\sim E^{-2}$, the conventional expectation from diffusive shock acceleration. Depending on the
turbulence model the initial energy spectrum can be significantly suppressed at lowest energies, which could be an observable feature to distinguish between different
turbulence realizations. This effect could lead to an efficient confinement of low energy particles, potentially leading to observable implication in terms of multi-messenger radiation and
cosmic-ray accumulated grammage within the bubble.
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Cosmology and Nongalactic Astrophysics
KiDS-Legacy: Joint analysis of second- and third-order cosmic shear
L. Linke, L. Porth, P. Burger et al. (+21 more)
Weak
lensing by large-scale structure is a powerful cosmological probe. While most analyses rely on second-order correlations, these are primarily sensitive to the parameter combination $S_8 = \sigma_8 (\Omega_m/0.3)^{0.5}$, limiting their ability to constrain $\Omega_m$ and other cosmological parameters independently. Higher-order statistics capture non-Gaussian features of the density field and can therefore break parameter degeneracies and extract more cosmological information from weak
lensing surveys. We present a joint analysis of second- and third-order
cosmic shear in the final data release of the Kilo-Degree Survey (KiDS-Legacy). We combine COSEBIs (Complete Orthogonal Sets of E-/B-mode Integrals) at scales between 2' and 300' with third-order aperture mass moments at scales between 4' and 32' to perform a joint analysis of second- and third-order statistics. Compared to previous KiDS analyses, we implement several methodological advances: an intrinsic
alignment model with
redshift and mass dependence, a
baryon correction model validated on multiple hydrodynamical simulations, and corrections for reduced shear and source clustering. Combining COSEBIs with third-order aperture mass statistics in KiDS-Legacy yields $\Omega_m = 0.297^{+0.056}_{-0.040}$ and $S_8 = 0.806^{+0.025}_{-0.023}$, significantly tightening the $\Omega_m$ constraints and more than doubling the figure of merit in the $\Omega_m$–$S_8$ plane compared to the two-point analysis alone. The third-order measurements pass stringent internal consistency tests, are fully compatible with the KiDS-Legacy 2-point constraints, other 2+3-point
lensing results and with Planck CMB measurements within $1\sigma$, providing no evidence for an $S_8$ tension and demonstrating the maturity of 3-point
cosmic shear as a key probe for forthcoming surveys.
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All authors L. Linke, L. Porth, P. Burger, J. Harnois-Déraps, S. Heydenreich, P. Schneider, M. Asgari, M. Bilicki, C. Georgiou, C. Heymans, H. Hildebrandt, H. Hoekstra, P. Jalan, B. Joachimi, S. Joudaki, K. Kuijken, S. Li, L. Moscardini, M. Radovich, R. Reischke, B. Stölzner, A. H. Wright, Z. Yan, Y.-H. Zhang
Quantum Physics
Minimality of the Stabilizer ZX Calculus
Harry K. Stoltz
The stabilizer fragment of the ZX calculus is amongst the most important fragments of the theory. Crucially, the stabilizer calculus can be described by a small collection of rewrites, most of which have been shown to be necessary by Backens–Perdrix–Wang (arXiv:1709.08903). However, two rules, describing the red/green compact-structure coincidence and the important bialgebra law, had not been shown to be necessary. We present two alternate interpretations, showing that both of these rules are individually necessary. Thus, this resolves a problem which has remained open for over a decade, and gives the first complete, minimal ruleset for the stabilizer ZX Calculus.
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Computational Physics · Cross-listed from cs.CE
A coupled finite element formulation for chemo-mechano-thermodynamical contact and its application to bonding and debonding
Roger A. Sauer
This work presents a finite element formulation for coupled chemo-mechano-thermodynamical large deformation contact. The formulation is based on the contact theory of Sauer et al. (2022) that contains six coupled (but separate) fields: the deformation and temperature of the two contacting bodies, as well as an interfacial bonding field and interfacial temperature. The latter is governed by the chemical and mechanical energy dissipation at the interface. Here the focus is placed on the
evolution of bonding and debonding, and how it is coupled to the mechanical and thermal contact state. Several elementary models are proposed for this based on a quadratic contact potential. The resulting contact formulation becomes very general and versatile, which is illustrated by several challenging examples. They include pressure- and gap- dependent bonding, exothermic bonding reactions, thermal hardening and thermal expansion, as well as simultaneous bonding and debonding. They are based on a monolithic finite element implementation using classical and isogeometric shape functions together with implicit time integration. Its full linearization, required for the Newton-Raphson solution method, is also provided for the six-field problem, as well as for several of its simplifications. If bonding sites are material points, the bonding variable can be condensed-out locally.
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High Energy Physics (Theory)
Nonadditivity in Quantum Field Theory: Replica Energies, Scaling Filters, and the Renormalization Group
Giacomo Santoni and Francesco Scardino
Extensive systems have a simple thermodynamic signature: the dimensionless canonical free energy scales homogeneously with the size of the system. We show that the failure of this scaling, measured by the replica energy ${\cal E}$, provides a useful bridge between statistical mechanics and
quantum field theory. The associated differential operator $(1-\frac1d L\partial_L)$ removes the leading bulk contribution to $\mathcal{F}=\beta F_{\rm can}=-\log Z$ and isolates the part that is sensitive to boundaries,
topology, defects, long-range forces, or other sources of nonadditivity. In
quantum field theory this thermodynamic idea has two closely related uses. For ordinary finite-volume or spherical partition functions, suitable higher-order versions of the same filter remove local counterterms and extract universal fixed-point data such as the central charge, the sphere free energy $F$, and the Euler anomaly coefficient $a$. For replica geometries with entangling defects, the same filtering principle gives the renormalized defect free energy. In $2+1$ dimensions, its $n\to1$ limit gives the entropic $F$-function, with the sign fixed below by the standard free-energy convention. We use this perspective to distinguish ordinary finite-size corrections,
topology-dependent constants in gapped phases, subextensive fracton degeneracies, and genuinely nonextensive systems with long-range interactions such as self-gravitating thermal matter. Replica energy therefore offers a common thermodynamic
language for additivity, defect free energies, and renormalization-group irreversibility.
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Quantum Physics
Fermions are fundamentally more nonlocal than Bosons
Fatemeh Moradi Kalarde, Sadra Boreiri, Xiangling Xu et al. (+5 more)
Bell's
theorem shows that entangled
quantum particles can exhibit correlations that classical particles cannot reproduce without an additional nonlocal resource, such as communication. In this sense,
quantum particles are fundamentally more nonlocal than classical ones, and
entanglement becomes unavoidable in physics. Here we prove the analogous result within
quantum theory itself: indistinguishable
fermions transmitted through a
quantum network can generate correlations that distinguishable particles or indistinguishable
bosons cannot reproduce without additional communication. In the same sense,
fermions are fundamentally more nonlocal than
bosons or distinguishable particles, motivating fermionic anticommutation and indistinguishability as unavoidable operational resources. Our result further implies that
fermions can strictly surpass all
qubit-based protocols for certain distributed computing tasks, demonstrating that a complete understanding of information processing requires going beyond
qubits to fermionic information carriers - febits.
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All authors Fatemeh Moradi Kalarde, Sadra Boreiri, Xiangling Xu, Lucas Tendick, Salman Beigi, Paolo Perinotti, Tommaso Guaita, Marc-Olivier Renou
Solar and Stellar Astrophysics
Three-Phase Evolution of Aspect Ratio in Fast and Slow CMEs from the Sun to 1 AU
Wageesh Mishra, Anjali Agarwal and Nandita Srivastava
Coronal mass ejections (CMEs) undergo significant
geometric evolution as they propagate from the Sun to 1 AU, influencing their radial size, expansion, and space weather impact. We investigate the
evolution of CME aspect ratio and expansion dynamics for four fast and four slow Earth-directed CMEs. Using multipoint coronagraphic observations with the Graduated Cylindrical Shell (GCS) model and corrected in situ measurements of associated
magnetic clouds (MCs) at 1 AU, we track the
evolution of aspect ratio from the low-middle corona to interplanetary space. We find that aspect ratio does not remain constant but exhibits a systematic three-phase
evolution: a rise phase in the low-middle corona ($\lesssim10$-$15\,R_{\odot}$), a saturation phase at intermediate heights, and then a decline phase in the interplanetary space. The ratio of radial expansion speed to leading-edge speed ($V_{\rm exp}/V_{\rm LE}$) decreases substantially from the corona to 1 AU, indicating a reduction in radial expansion efficiency during interplanetary propagation. The consistent
evolution of aspect ratio and $V_{\rm exp}/V_{\rm LE}$ suggests a transition from magnetically dominated expansion in the corona to a regime increasingly controlled by the heliospheric environment. We note that fast CMEs show stronger early expansion and evolve into larger, more radially extended structures, whereas slow CMEs exhibit a more gradual rise and a steeper decline. These results demonstrate that CME geometry evolves significantly during propagation and highlight the need to incorporate aspect ratio
evolution in models to improve predictions of CME size, arrival time, and geoeffectiveness.
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Lattice Field Theory
Soma Onoda
A central issue in
lattice formulations of
chiral gauge theories is how the anomaly cancellation mechanism of the continuum theory can be realized at finite
lattice spacing. In the present paper, based on non-Abelian bosonization, we propose a
lattice formulation of the bosonic theory corresponding to a two-dimensional non-Abelian
chiral gauge theory. In the continuum theory, the gauge anomaly of
chiral fermions is represented, in the bosonized description, as anomaly inflow from a three-dimensional Chern–Simons-type bulk contribution contained in a gauged Wess–Zumino–Witten model. Motivated by this structure, we introduce gauge-neutral spectator
fermions and use the resulting bosonized description. We then construct a
lattice counterpart of the gauged Wess–Zumino–Witten model with a three-dimensional bulk extension under appropriate smoothness conditions. A salient feature of this
lattice formulation is the cancellation of the left and right bulk contributions in the exponentiated action. This cancellation occurs even before taking the continuum limit when the anomaly-free condition is satisfied, namely when the left and right representations have identical quadratic indices. Thus, the present construction realizes the anomaly-cancellation mechanism at finite
lattice spacing via the bosonized description of two-dimensional anomaly-free
chiral gauge theories. Establishing the desired continuum limit remains an important open problem.
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High Energy Astrophysical Phenomena
Stellar mass loading drives dissipation and reacceleration in AGN jets: Explaining VLBI-Gaia offsets and constraining jet power
G. Fichet de Clairfontaine, M. Perucho, J. M. Martí et al. (+1 more)
Recent Very Long Baseline Interferometry (VLBI) and
Gaia astrometry reveal systematic milliarcsecond-scale offsets between the
radio and optical centroids of active
galactic nuclei (AGN). These "
radio-optical offsets" do not alter the standard opacity-driven interpretation of
radio core shifts. Instead, they indicate that the optical emission centroid is frequently displaced downstream of the
radio synchrotron optical depth $\tau = 1$ surface, implying that additional dissipation and particle reacceleration occur beyond the opacity
radio core within relativistic jets. We perform steady-state, axisymmetric relativistic magnetohydrodynamic (RMHD) simulations of AGN jets, including baryonic mass-load from
stellar winds, varying jet kinetic power, and
stellar core radius. Synthetic synchrotron emission maps in
radio and optical bands are generated via a radiative transfer code, and centroid offsets are extracted for comparison with observations. Parsec-scale
radio-optical offsets arise only for jet powers $L_{\rm j} \sim 10^{42.5} - 10^{44}\,\rm{erg}\,\rm{s}^{-1}$. In this regime,
stellar winds trigger jet deceleration at intrinsic distances of a few $10^2-10^3\,\rm{pc}$, shifting the optical centroid downstream and producing offsets of $\sim 0.1 - 4\,\rm{mas}$ (a few tens of parsecs at $z=1$). Offsets depend on
stellar distribution, viewing angle, and optical jet dominance, and vanish outside this power range. We reproduce the observed
redshift evolution of offset incidence, linking it to the
cosmic evolution of thermally pulsing asymptotic
giant branch (TP-AGB) mass loss. Although
stellar mass loading is unlikely to be the sole dissipation mechanism, its unavoidable presence in
galactic nuclei makes it a natural baseline for energy dissipation.
Radio-optical offsets therefore offer a constraint on AGN jet power and jet-host coupling, independent of traditional lobe-based methods.
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All authors G. Fichet de Clairfontaine, M. Perucho, J. M. Martí, Y. Y. Kovalev
Astrophysics of Galaxies
UV-to-optical insights into the BH$^*$ model in little red dots
Rosa M. Mérida, Marcin Sawicki, Chris J. Willott et al. (+2 more)
Little Red Dots (LRDs) are a heterogeneous class of objects, with several proposed scenarios for their physical nature and
evolution. While these theories have been tested on individual LRDs using limited spectral features, a systematic
Bayesian analysis of the LRD population incorporating the different models across a broad wavelength range is still lacking. In this study, we conduct a consistent ultraviolet (UV)-to-optical continuum fitting analysis of 99 LRDs at 2<z<6 using JWST/NIRSpec PRISM spectroscopy. Employing a modified version of Bagpipes-including blackbody (BB) emission affected by Balmer absorption,
stellar and nebular emission attenuated by
dust, and an active
galactic nucleus (AGN) component-we assess the performance of the black hole
star (BH*) model in describing the LRD population. We adopt broad priors and therefore do not impose any specific physical scenario. Our results show that only ~4% of LRDs with statistically robust solutions (81 objects in total) are best-fit by a BH* in the optical and a host
galaxy in the UV. ~9% of LRDs show BB-dominated optical continua but lack a
stellar component or exhibit AGN UV leakage. Most LRDs are dominated by
stellar and/or AGN emission in the optical, with minor BB contribution. When we adopt a prior that disfavors a strong AGN continuum to enforce BH*-like solutions, the percentage of BH* systems increases to ~35%, highlighting the strong degeneracy between a BH* solution and alternative scenarios. Even when BH*-like solutions are enforced, many LRDs still require a
stellar-dominated optical continuum. This could indicate limitations in the BH* model, as further supported by independent evidence, such as the detection of high-ionization emission lines in some LRDs.
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All authors Rosa M. Mérida, Marcin Sawicki, Chris J. Willott, Gaia Gaspar, Kartheik G. Iyer
Mesoscale and Nanoscale Physics
Gate-tunable spin-valley transport via carrier velocity in monolayer WSe$_2$
Otman Bouladiane, Hocine Bahlouli, Clarence Cortes et al. (+2 more)
We theoretically investigate
spin- and valley-resolved
quantum transport in monolayer tungsten diselenide (WSe$_2$) described by an effective massive Dirac
Hamiltonian. Particular
attention is devoted to a finite barrier region characterized by simultaneously modulated
Fermi velocity and scalar potential. The barrier velocity $v_2$ is related to the external velocity $v_1$ through a velocity ratio $\xi=v_2/v_1$, motivated by an optical analogy with the Snell-Descartes law. The exact refraction condition depends on the full
spin- and valley-resolved dispersion, and the simple ratio $\xi=v_2/v_1$ is recovered only in the massless, symmetric limit. The interplay of intrinsic
spin-orbit coupling in the conduction and valence bands, quantified by $\lambda_c$ and $\lambda_v$, with
spin- and valley-dependent Zeeman fields, $M_s$ and $M_v$, gives rise to substantial changes in the quasiparticle dispersion, leading to pronounced modifications of the transport characteristics. By solving the Dirac equation and enforcing current-conserving matching conditions at the interfaces, we compute the
spin- and valley-dependent transmission probability and conductance. Our results demonstrate that the barrier velocity, scalar potential, incidence angle, incident energy, and barrier width serve as effective control parameters for transport, giving rise to strong anisotropy and resonant tunneling features. Furthermore, we show that both the magnitude and orientation of
spin- and valley-polarized currents can be continuously tuned via velocity and potential modulation. These findings establish combined velocity and potential engineering as a powerful theoretical framework for controlling
spin-valley physics in two-dimensional transition-metal dichalcogenides.
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All authors Otman Bouladiane, Hocine Bahlouli, Clarence Cortes, David Laroze, Ahmed Jellal
Geophysics · Cross-listed from cs.CE
Local Stress Redistribution Controls Interactions between Hydraulic Fractures and Pre-existing Fractures
S. Shandilaya, M. Alaleeli, S.H. Kim et al. (+2 more)
Hydraulic fracture (HF) propagation in naturally fractured formations is strongly influenced by local stress states near pre-existing natural fractures (NFs). The role of NF-induced shear deformation and stress redistribution in controlling HF trajectories remains poorly characterized. This study investigates how NF-induced stress redistribution governs HF-NF interactions through coupled laboratory experiments and poroelastic extended finite element simulations on intact and pre-fractured PMMA specimens under plane-strain conditions. Digital image correlation provides full-field measurements of displacement and strain
evolution during mechanical loading and hydraulic fracturing. Under fixed-base, lateral confinement, and vertical compression boundary conditions, inclined NFs induce asymmetric stress redistribution and shear deformation, generating distinct local stress states prior to fluid injection. The results demonstrate that the HF trajectory is governed by the sign and spatial distribution of shear stress and shear strain components generated by NF orientation relative to the far-field maximum principal stress. Shear deformation that promotes compressive stress development adjacent to the NF causes the HF to deflect away, whereas shear deformation that reduces the effective normal stress along the NF promotes fracture attraction and linkage. Corresponding numerical reproduction of HF
curvature in pre-fractured specimens requires mixed-mode (Mode I-II) fracture energy release criteria, while the intact specimen propagates in pure Mode I. Overall, the findings reveal a transition from tensile opening to shear-assisted mixed-mode propagation as local stress states evolve due to the presence of NFs, providing a mechanistic basis for predicting and controlling fracture trajectories in subsurface stimulation and storage applications.
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All authors S. Shandilaya, M. Alaleeli, S.H. Kim, M. Mobasher, S. Roshankhah
High Energy Physics (Theory)
Entanglement generation between field modes mediated by a fluctuating conducting wall
Luca Giovanni Cammarata, Tommaso Fazio, Roberto Passante et al. (+1 more)
We consider a movable conducting plate of finite mass, between two fixed ones, whose mechanical degrees of freedom are treated
quantum-mechanically and bound to its
equilibrium position by a harmonic potential. The movable wall is thus subjected to
quantum fluctuations of its position. This creates a system of two subcavities separated by the movable fluctuating plate, and two massless one-dimensional scalar fields, one in each subcavity. This system is described by an appropriate generalization of the Law
Hamiltonian. The presence of the movable wall yields an effective plate-fields interaction, as well as an effective interaction between the field modes. We obtain, at the second order in perturbation theory, the ground state of the interacting system and the reduced density operator of the fields in each subcavity by tracing out the wall's degrees of freedom. We calculate the
entanglement between two field modes, one in each cavity, by evaluating analytically the negativity; we then evaluate numerically also the total multimode negativity. Our results show that in both cases the fields in the two subcavities are entangled, in contrast to the case in which the wall is fixed in space. We discuss the amount of the field
entanglement present as a function of relevant physical parameters of the system such as the mass and oscillation frequency of the movable wall, its distance from the fixed walls and the frequencies of the field modes considered.
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All authors Luca Giovanni Cammarata, Tommaso Fazio, Roberto Passante, Lucia Rizzuto
Chemical Physics
Transferable Machine Learning of Electronic Hamiltonians with Superposition-of-Atomic-Potentials Features
Chaoqun Zhang, Christian Venturella, Enzhi Chen et al. (+1 more)
Machine learning (ML) of electronic
Hamiltonians offers a unified route to electronic wave functions and physical observables. We introduce a
Hamiltonian learning framework built on electronic features derived from the superposition-of-atomic-potentials (SAP) approximation, an efficient self-consistent-field initial guess that captures essential electron-electron screening. SAP quantities define a
symmetry-adapted intrinsic atomic orbital learning basis and provide physics-informed inputs to an orbital-based graph neural network that predicts converged Kohn-Sham Fock
matrices. To extend the approach to larger basis sets, we further develop a downfolding scheme that predicts large-basis electronic structure from minimal-basis features. On the QM9
dataset, the model accurately reproduces frontier and core orbital energies, dipole moments, and the full density of states. For organic charge-transport materials, it yields accurate intermolecular transfer integrals for benzene, tetracyanoquinodimethane (TCNQ), and tetrathiafulvalene (TTF) dimers, and transfers to unseen substituted-benzene heterodimers with a mean absolute error of 4.8 meV. These results establish SAP-based ML of electronic
Hamiltonians as a transferable and scalable tool for high-throughput electronic-structure prediction.
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All authors Chaoqun Zhang, Christian Venturella, Enzhi Chen, Tianyu Zhu
Atomic Physics
Photon Cycling and Laser Cooling of an Asymmetric Top Molecule
Grace K. Li, Giseok Lee, Jack Mango et al. (+8 more)
We realize two-dimensional magnetically-assisted Sisyphus
laser cooling of an asymmetric top molecule (ATM), calcium monoamide (CaNH$_2$). Vibrational state closure is achieved with $41.1 \pm 6.3$
photons scatters using optical pumping of the $X[3_1]$ state.
Photon-cycling measurements show good agreement with branching ratios determined by dispersed fluorescence spectroscopy. Rotational closure is maintained by driving the $X[1_{11}] \to A [0_{00}]$ transition. The observed absence of additional state leakage channels broadens the scope of molecular
laser cooling to include ATMs, which are the most general
geometric class of molecules and possess the richest internal structure. Future applications of
quantum controlled ATMs include new
quantum information platforms and searches for physics beyond the Standard Model.
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All authors Grace K. Li, Giseok Lee, Jack Mango, Hana Lampson, YongWoong Lee, Winston Wang, Avikar Periwal, Nathaniel B. Vilas, Alexander Frenett, Loïc Anderegg, John M. Doyle
Plasma Physics
Mixed Hermite-Legendre spectral method for kinetic plasma simulations
Opal Issan, Gian Luca Delzanno and Vadim Roytershteyn
Kinetic collisionless
plasma equations are commonly solved via spectral methods in velocity space. The most commonly used spectral method is based on Hermite
polynomials with a Maxwellian weight, as this basis efficiently represents near-Maxwellian distributions with relatively few degrees of freedom. An alternative approach uses Legendre
polynomials, which are better suited for resolving strongly non-Maxwellian features. In this paper, we propose a mixed method that combines the Hermite and Legendre expansions. The mixed method is particularly advantageous for problems in which non-Maxwellian features are localized in velocity space, such as beams and plateaus. We demonstrate analytically and numerically that the mixed method conserves total mass, momentum, and energy by imposing certain constraints. The numerical results show that, for the same number of degrees of freedom, the proposed mixed method can achieve improved accuracy in comparison to the individual Hermite or Legendre methods, while maintaining comparable computational cost.
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Quantum Physics
Quantum repeater segment with free-space coupled co-trapped ions using telecom photon interference
Max Bergerhoff, Pascal Baumgart, Christian Haen et al. (+5 more)
A
quantum repeater segment is a basic building block of a
quantum repeater, generating buffered
entanglement of
quantum memories to connect
quantum repeater
cells. It also enables the connection between
quantum computers. In the implementation we present here,
photons emitted from two co-trapped free-space coupled $^{40}$Ca$^+$ ions are converted to the telecom-C band and interfered after transmission over 440$\,$m of optical fiber (220$\,$m per arm), where a photonic Bell measurement is performed to create
entanglement between the
memories. With this scheme we generate an entangled $\left|\Psi^+\right\rangle$ Bell state with $\ge 68(8)\,$% fidelity, highlighting trapped $^{40}$Ca$^+$ ions as a promising
quantum repeater hardware platform.
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All authors Max Bergerhoff, Pascal Baumgart, Christian Haen, Jonas Meiers, Tobias Bauer, Jonas Haferkamp, Christoph Becher, Jürgen Eschner
High Energy Physics (Phenomenology)
Sensitivity to top-quark couplings in diboson production at lepton colliders
Eugenia Celada, Víctor Miralles and Eleni Vryonidou
We study the next-to-leading order electroweak corrections to $e^+e^- \rightarrow W^+W^-$ from dimension-six two-
fermion top-
quark operators in the Standard Model Effective Field Theory. We compute analytical and numerical results for future electron-positron
colliders, focusing on the proposed LEP3 and FCC-ee that will operate at centre-of-mass energies below the $t \bar{t}$ production threshold. We compare the indirect sensitivity arising from virtual corrections to $WW$ production to that from $ZH$ production, and to the current constraints from LEP and LHC data. We show that NLO corrections can provide competitive sensitivity to these operators. This work represents a first step towards the systematic computation of electroweak corrections to $W$-pair production at
lepton colliders in the SMEFT, whose impact can then be properly assessed in global analyses.
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Materials Science
Effect of polar distortions on the linear and nonlinear anomalous Hall conductivity of altermagnetic $\alpha$-MnTe
Mathews Benny, Sahar Izadi Vishkayi, Amar Fakhredine et al. (+2 more)
Altermagnetic $\alpha$-MnTe with Néel vector along the $y$-axis exhibits a finite anomalous
Hall conductivity (AHC) and weak ferromagnetism along the $z$-axis. As already demonstrated in the bulk, there is the breaking of the C$_6$
symmetry by the in-plane Néel vector, leaving a C$_2$-type
magnetic symmetry. The surface of $\alpha$-MnTe breaks the C$_2$, leaving only a time-reversed mirror
symmetry with respect to the $x=0$ plane. Therefore, we demonstrate that on the surface, the interplay between breaking of the
crystal symmetry and Néel vector orientation produces a reduction of the space group from hexagonal P6$_3$/mmc to orthorhombic Amm2. As a result, the surface exhibits not only a polar distortion along the $z$-axis, but also a polar distortion and a weak ferrimagnetism along the $y$-axis. To describe the surface of MnTe in an accessible way, we simplify the problem and examine the effect of the in-plane electric field in bulk MnTe. Moreover, as a doped ionic
semiconductor, the properties of MnTe can be influenced by
lattice polarization under an applied electric field. We investigate the interplay between the intrinsic anomalous
Hall effect and
lattice polarization, showing that polarization effects can substantially affect the AHC. Since the electric field breaks inversion
symmetry, this contribution from the
lattice polarization coexists with the non-linear anomalous
Hall effect, highlighting the rich transport phenomenology of altermagnets.
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All authors Mathews Benny, Sahar Izadi Vishkayi, Amar Fakhredine, Chanchal K. Barman, Carmine Autieri
Quantum Physics
Partitioned Iterative Quantum Scheduling of Satellites for Urgent Disaster Response: Case study of Wildfire
Lucas T. Braydwood, Taejin Park, Hirofumi Hashimoto et al. (+4 more)
The standard in Earth-observation tasks today is having near real-time access to surface images in response to changing conditions. For instance, as urban environments interface more with wildlands and wildfires become less predictable, their tracking with satellite resources becomes essential. This requires the coordination of increasingly large constellations of satellites, giving rise to challenging computational problems. With wildfire detection and tracking as a backdrop, we investigate the power of special purpose and novel computing paradigms to tackle the ensuing satellite scheduling problems, making a compelling case for
quantum algorithms. We bring
quantum scheduling
algorithms closer to implementation by examining both the emerging iterative
quantum algorithm framework, which comes with analytic guarantees compared to some classical
algorithms, and distributed
quantum computing methods whose relevance is on the rise as utility-scale problems begin to get solved with
quantum computers. Drawing strength from several computing fronts, we develop a distributed/parallelization scheme in conjunction with the
quantum algorithm design and apply these techniques to real-world
datasets for wildfire detection. While our
quantum subprocesses are currently too small to see significant
quantum advantage, our results validate the utility of these techniques, and continue forging the path toward distributed
quantum computing.
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All authors Lucas T. Braydwood, Taejin Park, Hirofumi Hashimoto, Zoe Gonzalez Izquierdo, Andrew Michaelis, Eleanor Rieffel, Shon Grabbe
High Energy Physics (Phenomenology)
$\boldsymbol{\chi_{c1}}(3872)$ and its Partners in the Diabatic Born-Oppenheimer Approximation for QCD
Fareed Alasiri, Eric Braaten and Roberto Bruschini
In the Born-Oppenheimer approximation for QCD, the exotic hidden-charm tetraquark
meson $\chi_{c1}(3872)$ is a near-threshold bound state in Born-Oppenheimer potentials associated with an isospin-0 adjoint
meson. The $\chi_{c1}(3872)$ is the $1^{++}$ member of a heavy-
quark spin-
symmetry multiplet whose other members have $J^{PC}$
quantum numbers $0^{++}$, $1^{+-}$, and $2^{++}$. We introduce a simple model for the Born-Oppenheimer potentials that interpolates between the adjoint-
meson potential at short distances and the triplet-
meson-pair potential at large distances. We take into account the
spin splittings of charm
mesons nonperturbatively for the first time by solving the diabatic Schrödinger equation. We also take into account the
spin splittings of the adjoint
meson as well as a narrow avoided crossing with the quarkonium potential. We tune the energy of $\chi_{c1}(3872)$ to the $D^* \bar{D}$ threshold and then calculate the
spin splittings of the other members of the multiplet and their decay widths into charm-
meson pairs. We also calculate the energies and decay widths of the corresponding multiplet of hidden-bottom tetraquarks. These calculations provide a template for the quantitative analysis of all hidden-heavy
hadrons using the Born-Oppenheimer approximation for QCD.
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Fluid Dynamics
Laser-Liquid Interaction in Laser-Induced Forward Transfer (LIFT) Printing: A Multiscale Perspective on Bubble Dynamics and Material Ejection
Shuqi Zhou, Abdol Hadi Mokarizadeh and Ben Xu
Laser-induced forward transfer (LIFT) is a nozzle-free
laser-assisted printing method that provides an advanced manufacturing route for spatially selective deposition of functional inks, nanoparticle suspensions,
polymers, hydrogels, biological materials, and other difficult-to-nozzle formulations. The apparent simplicity of LIFT, however, conceals a strongly coupled
laser-
liquid interaction.
Laser energy is absorbed within a confined donor architecture, converted into thermal and
plasma responses, and then transformed into bubble-mediated motion of the donor material. The cavitation bubble provides the transient mechanical bridge between optical energy deposition and the hydrodynamic ejection process. This chapter presents LIFT from a multiscale perspective centered on bubble dynamics and material ejection. It first reviews major LIFT donor architectures. Then, it examines how donor ribbon design, absorbing-layer properties,
laser parameters, material rheology, control bubble inception/growth, jet formation, droplet breakup, and final deposition. Modeling approaches are discussed as tools for connecting experimental observations across time and length scales, ranging from reduced-order estimates to interface-resolving simulations and data-driven process maps. As one illustrative mechanistic example, thermal-only,
plasma-mediated, and coupled
plasma-thermal-thermoelastic frameworks for early-stage bubble inception are briefly compared to show how different inception assumptions can provide initial conditions for downstream bubble growth and jetting models. This chapter concludes by identifying opportunities for bubble-aware donor design, time-resolved diagnostics,
benchmark datasets, and predictive LIFT process maps based on intermediate bubble and jet observables.
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