Strongly Correlated Electrons
Near-infrared magnetic linear and non-reciprocal directional dichroism in the chiral antiferromagnet SmFe3(BO3)4
B. Beke, B. Szász, I. A. Gudim et al. (+2 more)
We investigated the influence of
antiferromagnetic (AFM) order on the near-infrared optical re- sponse of SmFe3(BO3)4 by polarization-resolved, magneto-optical spectroscopy. Below the Néel temperature, we observed pronounced
magnetic linear dichroism at the 4f -4f transitions of Sm3+. By rotating the order parameter of the easy-plane AFM ground state using
magnetic fields, we demonstrated the
magnetic field control of linear dichroism, and deduced polarization selection rules. In addition, we detected non-reciprocal directional dichroism for several 4f -4f transitions. The non-reciprocal absorption appears in the
symmetry-allowed toroidal geometry when the in- plane
magnetic field is normal to one of the two-fold rotation axes. These results indicate a strong interference between electric- and
magnetic-dipole excitations for transitions showing non-reciprocal absorption. The observed optical anisotropies provide a promising path to detect the in-plane orien- tation of the AFM order, enabling imaging and time-resolved studies of the AFM order parameter in rare-earth ferroborates.
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All authors B. Beke, B. Szász, I. A. Gudim, D. Szaller, S. Bordács
Soft Condensed Matter
Temperature dependence of surface tension in aqueous sodium dodecyl sulfate solutions
Jong Cheon Lee and Ildoo Kim
We report measurements of the surface tension of aqueous sodium dodecyl sulfate solutions at sixteen concentrations from 0.17 to 43$\,$mM, spanning 0.02 to 5 times the room-temperature critical micelle concentration (cmc), and at temperatures from 26 to 83$\,$$^\circ{\rm C}$, using the Wilhelmy plate method. At the lowest concentration the surface tension decreases with temperature, as it does for pure water. Above about 0.4$\,$mM, however, it increases: the temperature coefficient changes sign at a concentration of 0.3 to 0.8$\,$mM, roughly a tenth of the cmc, and reaches $+0.53\,\rm mN\,m^{-1}\,K^{-1}$ near 3$\,$mM, three times the magnitude of that of pure water and of the opposite sign. Above the cmc the surface tension is nearly independent of temperature, saturating at $35.2\pm0.3\,\rm mN\,m^{-1}$. The behavior cannot be attributed to the temperature dependence of the cmc, which is an order of magnitude too weak. It is instead consistent with a surfactant layer that thins as the temperature rises. The results imply that the sign and magnitude of thermocapillary stresses in SDS solutions can be selected through the concentration.
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Instrumentation and Methods for Astrophysics · Cross-listed from cs.DL
Best practices in software citation
Phil R. Van-Lane, Floor S. Broekgaarden, Daniel S. Katz et al. (+11 more)
Software is both a foundational tool and a primary output of modern computational research, yet citation practices for software remain inconsistent, incomplete, and rarely machine-actionable. Existing infrastructure designed for paper and data citation does not adequately serve the distinct needs of software citation, leaving a gap that impedes reproducibility, misattributes scholarly credit, and obscures the labor embedded in research pipelines. Drawing on a NASA-funded community workshop held in April 2026, we present an analysis of four interconnected themes: (I)~the cultural barriers to consistent citation practice; (II)~the need for clearer community norms and conventions; (III)~gaps in existing technical infrastructure and workflow; and (IV)~the emerging challenges posed by AI-assisted research. For each theme we identify targeted interventions and assign responsibility across stakeholder groups. We conclude that meaningful progress requires simultaneous action on technical and cultural fronts. Journal editors and publishers represent the single highest-leverage point for accelerating this change, and correct citation must become the path of least resistance within researchers' existing workflows.
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All authors Phil R. Van-Lane, Floor S. Broekgaarden, Daniel S. Katz, Bhavesh Patel, Pengyin Shan, Jonathan Starr, Samantha Teplitzky, Peter K.G. Williams, Alice Allen, Lucas M. de Sá, Andrew Fullard, Sandra Gesing, Tom Wagg, Andrea Zonca
Quantum Physics
Polynomial-time local-unitary equivalence of graph states
Yuxuan Zhang
Local-
unitary (LU) equivalence asks whether two
quantum states differ only by independent changes of basis on their
qubits. For graph states, whether this relation can be decided in
polynomial time has remained open for over a decade. We give a deterministic
algorithm that decides LU equivalence for graphs on $n$ labelled vertices in $\widetilde O(n^{6.38})$ bit operations and constructs exact single-
qubit unitaries whenever the states are equivalent. Building on Claudet and Perdrix's quasipolynomial
algorithm, we replace the enumeration of vertex subsets by a compact system of constraints generated from pairs and triples. The remaining graph transformation is found by solving linear equations over the binary field. These new steps cost $\widetilde O(n^5)$ bit operations; the inherited graph preprocessing sets the overall bound. We also count the local-Clifford (LC) classes of graph states within any LU class: their number is a power of two, computable within the same bound. For any given graph state, this decides whether single-
qubit Clifford gates reach every graph state in its LU class, and supplies a counterexample when they do not. The method also decides LU equivalence of stabilizer codes encoding one logical
qubit.
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Quantum Physics
Good Quantum Locally Testable Codes from Lossless Cubical Complexes
Itay Cohen, Itai Leigh, Assaf Reiner et al. (+2 more)
Sipser and Spielman constructed LDPC codes from either bipartite spectral expanders or one-sided lossless expanders. In higher dimensions, spectral expansion similarly played a central role in the constructions of asymptotically good classical LTCs and qLDPC codes by Dinur, Evra, Livne, Lubotzky, and Mozes and by Panteleev and Kalachev. Alternatively, Lin and Hsieh constructed classical LTCs and qLDPC codes from two-dimensional lossless cubical complexes. In this work we develop the higher-dimensional lossless approach. We do not construct the required high-dimensional lossless cubical complexes; rather, we investigate what their existence would imply. We associate with a high-dimensional cubical complex a level chain complex, whose chain groups are supported on the level sets of the Boolean cube rather than on its
cells. Our main technical contribution is a clean local-to-global
theorem for this structure: suitable one-dimensional lossless expansion in the directional graphs implies small-set coboundary expansion of the global level complex. As a consequence, sufficiently imbalanced, two-sided lossless four-dimensional cubical complexes give rise to asymptotically good
quantum locally testable codes. We expect the local-to-global principle developed here to have further applications.
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All authors Itay Cohen, Itai Leigh, Assaf Reiner, Amnon Ta-Shma, Elad Tzalik
High Energy Physics (Phenomenology)
Charged scalar portal dark matter with $U(1)_Y$ non-restoration and gravitational waves
Debasish Borah, Dhruv Ringe and Indrajit Saha
We explore the possibility of reviving scalar singlet dark matter (DM) with a minimal extension by a charged singlet scalar which also leads to hypercharge non-restoration in the early Universe. The minimal scalar singlet DM annihilating via the
Higgs portal is tightly constrained by direct-detection experiments, leaving a desert between two narrow regions of the DM mass near the
Higgs resonance and around a TeV. The addition of a charged scalar portal revives this desert region while keeping the one-loop direct-detection rate within reach of current and future experiments. A non-zero
vacuum expectation value of the charged scalar at high temperature can also drive $U(1)_Y$ hypercharge
symmetry non-restoration in the early Universe. In a subset of the parameter space, the charge-breaking minimum gets restored to the standard
Higgs minimum via a strong first-order phase transition, making it a viable scenario for the generation of
baryon asymmetry of the Universe via leptogenesis. A large part of the parameter space consistent with DM relic, direct-detection,
symmetry non-restoration and other experimental bounds can be probed at upcoming GW detectors such as LISA, BBO and DECIGO.
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Quantum Physics
First-quantized quantum simulation with non-local potentials by matrix-product-state encoding
Kazuki Tsuoka, Taichi Kosugi, Masari Watanabe et al. (+2 more)
Quantum simulations based on first-quantized approaches can offer lower space and gate complexities than second-quantized approaches. The gate requirements for these simulations can be further reduced by employing pseudopotentials, a technique widely used in classical
quantum chemistry calculations to decrease the number of simulated electrons. However, implementing pseudopotentials in
quantum circuits remains challenging due to their non-local nature. In this study, we proposed a method to efficiently implement non-local potentials using
matrix product state (MPS) encoding. MPS encoding allows us to efficiently implement a Trotter step operator with a
circuit depth of $O(\mathrm{deg}(V_{\mathrm{loc}}) n^{\mathrm{deg}(V_{\mathrm{loc}})} + 8Lnn_{\mathrm{atom}}\chi^2 + 2n^2)$, where $\mathrm{deg}(V_{\mathrm{loc}})$ is the degree of the
polynomial local potential, $n_{\mathrm{atom}}$ is the number of atoms in the system, $L$ is the maximum number of projector functions across all atoms, and $n$ is the number of
qubits used to represent the binary-encoded wave function in one-dimensional space. We demonstrated the effectiveness of this approach by applying it to a model of the ionization of a one-dimensional hydrogen atom driven by an ultrashort
laser pulse. Our results showed that MPS encoding significantly reduces the required
circuit depth compared to a direct
unitary decomposition, providing a pathway for practical first-quantized simulations.
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All authors Kazuki Tsuoka, Taichi Kosugi, Masari Watanabe, Hirofumi Nishi, Yu-ichiro Matsushita
Quantum Physics
Near-Optimal Ground-State Preparation without Controlled Hamiltonian Evolutions
Dhrumil Patel, Steven T. Flammia and Raul Garcia-Patron
Ground-state preparation, energy estimation, and property estimation are fundamental tasks in
quantum simulation. Existing ground-state preparation
algorithms achieve near-optimal complexity using block encodings or controlled
Hamiltonian evolution, raising a natural question: is controlled
Hamiltonian evolution necessary, or can the same scaling be attained in the weaker access model that provides access to only uncontrolled
Hamiltonian evolution? We resolve this question by giving two
algorithms that access the input
Hamiltonian $H$ only through queries to $U_H$ and its inverse $U_H^\dagger$, where $\|H\|\le\alpha_H$ and $\tau=\Theta(1/\alpha_H)$. Given an input state with ground-state weight at least $\eta$ and a spectral gap of $H$ of at least $\gamma$, our first
algorithm uses fresh copies of the input state and requires $\widetilde O(\alpha_H/(\gamma\eta))$ queries to $U_H$ and $U_H^\dagger$, while our second
algorithm uses coherent access to the input-state preparation
unitary and its inverse to improve this complexity to $\widetilde O(\alpha_H/(\gamma\sqrt{\eta}))$. The latter bound matches the known lower bound up to logarithmic factors, showing that
algorithms with additional access to controlled
Hamiltonian evolution cannot improve the query complexity for ground-state preparation beyond logarithmic factors. Both
algorithms are based on a simple mechanism that we call the spectral descent principle, in which the
algorithm starts from the input state $|\psi\rangle$ and progressively descends through the energy spectrum, moving closer to the ground state until the desired fidelity is reached. We also extend this framework to ground-state property and energy estimation and give explicit complexity guarantees for both tasks.
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Quantum Physics
Blind Unforgeability implies Plus-One Unforgeability
Mehil Agarwal, Calliope S. Reimann and Fang Song
We prove that
quantum blind-unforgeability implies
quantum plus-one unforgeability, settling an open question in the literature. Since plus-one unforgeability is known not to imply blind-unforgeability, our result establishes that blind-unforgeability is strictly stronger than plus-one unforgeability in the
quantum setting. The implication is proven using a new smoothing technique that coherently rescales the query histories of a
quantum-query
algorithm in a black-box manner. This enables us to transform any successful plus-one attacker into a blind-unforgeability attacker with only inverse-
polynomial loss. Our proof represents a conceptual shift from merely extracting a useful query history as in earlier attempts, which we show inevitably fails in general, to first coherently reshaping how query histories interfere.
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High Energy Physics (Theory)
Mock Modularity, Resurgence, and Dual False Theta Functions
Mrunmay Jagadale
The $\hat{Z}$ invariant of a three-
manifold $M_{3}$, a half-index of the $3d$ $\mathcal{N}=2$ theory $T[M_{3}]$, is well understood for negative-definite plumbed three-
manifolds. For orientation-reversed
manifolds, however, the known formulas fail to produce $q$-series, and making sense of the operation $q \rightarrow q^{-1}$ remains a central open problem. Seifert
manifolds, whose $\hat{Z}$ invariants are built from false theta functions, offer a natural testing ground. We study “dual false theta functions”, the objects that should replace false theta functions under orientation reversal. Two characterizations of these duals exist in the literature: a modular one, based on mock modularity with a prescribed shadow, and a resurgent one, based on Borel–Mordell integrals and transseries. We prove that the two characterizations are equivalent. We construct a new family of dual false theta functions for values of positive integer $p$ satisfying a Pell-equation condition. Its members are built from Zwegers' indefinite theta functions, have integer coefficients, and have effective central charge $c_{\text{eff}} \leq 1$. We also show that the mock theta functions of Li and Schwagenscheidt satisfy these characterizations and arise from a natural regularization of the divergent product $\eta^{3}(\tau)\psi_{p, a}(- \tau)$.
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High Energy Physics (Phenomenology)
Unified description of longitudinal and transverse parton dynamics in cold nuclear matter
Weiyao Ke
We present a unified description of longitudinal momentum
evolution and transverse-momentum broadening in cold
nuclear matter using soft collinear effective theory with Glauber
gluon interactions (SCET$_{\rm G}$). In a finite
nucleus, Landau–Pomeranchuk–Migdal interference couples medium-induced energy loss to the transverse scale resolved by the observable. Our framework combines RG
evolution of impact-parameter-dependent energy loss with BFKL-type rapidity
evolution of the collision kernel, improved by kinematical constraints and running coupling. With a common set of cold-
nuclear-matter parameters, it accounts for the main
nuclear modification patterns in semi-inclusive DIS and Drell–Yan production and provides predictions for TMD
hadron multiplicities at the EIC. We also discuss the one-point energy correlator in DIS, whose energy weighting suppresses the leading final-state energy-loss contribution. In the EIC kinematics studied, the residual dynamical corrections are small, leaving the
nuclear modification dominated by the initial-state
nuclear parton distributions.
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Astrophysics of Galaxies
Star Formation Mitosis: The Effects of Particle Splitting on the Star Formation Outcome
Shivan Khullar, Michael Y. Grudić, Christopher D. Matzner et al. (+3 more)
Particle splitting can increase the dynamic range in Lagrangian astrophysical simulations by several orders of magnitude. However, such methods can introduce numerical noise that may affect the rate of convergence, particularly for collapse problems where fragmentation could be artificially suppressed or enhanced. Thus it is necessary to determine how these errors propagate to key quantities of interest, and to correct or mitigate them where possible. Using GIZMO's MFM-MHD method, we perform a set of $\approx 220$ simulations of a uniform-density turbulent gas sphere undergoing collapse, systematically varying the cloud mass and radius, feedback physics, initial resolution, the pace and cadence at which we split particles and the sink (accreting) or single-age
stellar population (SSP; non-accreting) particle formation prescription. Crucially, we compare with control runs that start with uniformly-high resolution without splitting. While we find no evidence for artificial fragmentation caused by splitting particles, particle splitting runs have a smoother density field than their non-splitting counterparts. Due to this, particle splitting runs exhibit minor differences in the density and
turbulence statistics. However, they form about the same total
stellar mass as the control non-splitting runs, albeit with a slightly different mass spectrum. As a result, particle splitting runs have a different evolutionary history, compared to runs without particle splitting, especially when
stellar feedback is present. Despite the changes seen in runs where we split particles, the numerical solution lies within the scatter inherently present in these chaotic systems, which we model by modifying the initial turbulent velocity field. Our results here argue that particle splitting generally “works" for
star formation applications, despite some systematic differences in the specifics.
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All authors Shivan Khullar, Michael Y. Grudić, Christopher D. Matzner, Philip F. Hopkins, Norman Murray, Claude-André Faucher-Giguère
Instrumentation and Methods for Astrophysics
Prototyping the Next-Generation Spectrograph for Space Exploration: Digital Micromirror Device-based Multi-Object Spectrograph (DMD-MOS) Calibration and Performance Assessment
Jiayi Emma Xu, Sarik Jeram, Shaojie Chen et al. (+7 more)
Abandoning the traditional approaches to multi-object spectrographs, the Digital Micro-mirror Device-based Multi-Object Spectrograph (DMD-MOS) leverages a robust, elegant method for creating multi-object spectroscopy slit masks through use of a DMD, which is an array of microscopic flat mirrors where each micro-mirror can be addressed to physically flip between two discrete angles. We have designed two optical channels for DMD-MOS - one for each of these two positions: 1) an imaging channel that can be used for multi-object target selection and 2) a spectrograph channel. Using this two-channel approach, DMD-MOS can simultaneously image the
telescope field of view (FOV) with the imaging channel and actuate the specific DMD micro-mirrors to send light from chosen targets into the spectrograph channel. In this work, we present the results of our laboratory testing of DMD-MOS including spectral resolution, line spread function, wavelength coverage, and the mapping between the DMD and imaging channel planes, the latter of which enables DMD-MOS and our control software to instantaneously configure the DMD to observe chosen target(s) in the acquisition field.
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All authors Jiayi Emma Xu, Sarik Jeram, Shaojie Chen, Ting S. Li, Ziang Chen, Zain Azam, Adi Khandelwal, Mark Barnet, Yixuan Cheng, Suresh Sivanandam
High Energy Astrophysical Phenomena
X-ray Through Radio Observations and Modeling of the Soft X-ray Flash GRB 250419A
Genevieve Schroeder, Anna Y. Q. Ho, Gavin P. Lamb et al. (+24 more)
Soft X-ray flashes (XRFs) are predicted from a variety of hypothesized phenomena, including "dirty fireballs" (relativistic jets with significant
baryon loading), and gamma-ray bursts viewed marginally off-axis. For a given burst, detailed multiwavelength observations are necessary for distinguishing between possible progenitor scenarios, but the number of XRFs with such data remains small. Here we present X-ray, optical, and
radio (mm to cm) data of GRB 250419A, an XRF (with peak energy $E_p<4\,$keV) discovered by the Space-based multi-band astronomical Variable Objects Monitor. We observe a clear achromatic break in the X-ray and optical bands, and likely two spectral components in the
radio emission. The afterglow is similar to the long-duration gamma-ray burst population, but slightly underluminous, and the optical afterglow has an unusually shallow decay phase at $\lesssim2\,$d. We find that the event is well explained by a high-Lorentz factor jet with low kinetic energy ($E\sim10^{49}$-$10^{50}\,$erg), with energy injection that could arise from radial stratification and/or the jet being viewed marginally off-axis. We conclude that at least some X-ray flashes are an extension of classical gamma-ray bursts down to lower energies.
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All authors Genevieve Schroeder, Anna Y. Q. Ho, Gavin P. Lamb, Tanmoy Laskar, Daniel A. Perley, Ore Gottlieb, Tomas Ahumada, Igor Andreoni, Aleksandra Bochenek, Michael Bremer, Michael Camilo, Jonathan Carney, S. Bradley Cenko, Alessandra Corsi, Michael W. Coughlin, James Freeburn, Erica Hammerstein, Rahul Jayaraman, Mansi M. Kasliwal, Noel Klingler, Brendan O'Connor, Cassie Sevilla, Gokul P. Srinivasaragavan, Robert Stein, Jada L. Vail, Sylvain Veilleux, Lin Yan
Instrumentation and Methods for Astrophysics
Automated multi-stressor optical fiber focal ratio degradation and throughput characterization system for future massive multiplex spectroscopic survey
Daksh Singh, Ting S. Li, Sarik Jerma et al. (+1 more)
Future spectroscopic survey facilities such as Spec-S5 and the Wide-Field Spectroscopic
Telescope (WST) will contain more than 25,000 optical fibers. Characterizing the focal ratio degradation (FRD) and throughput of these fibers is essential for spectroscopic calibration, sky subtraction, and overall instrument performance, but manual testing of such large fiber populations is prohibitively time-consuming. In this work, we present an automated multi-stressor optical fiber characterization platform capable of measuring both FRD and relative throughput while systematically varying optical and mechanical stress conditions. The system enables characterization as a function of input angle, wavelength, bend radius, twist angle, and externally applied load, while also allowing combinations of stressors to be investigated simultaneously. A custom software framework automates hardware control, data acquisition, and data analysis, enabling large characterization campaigns to be performed with minimal user intervention. Validation measurements performed on a multimode optical fiber demonstrate the ability of the platform to resolve both pronounced and subtle stress-dependent variations in FRD and relative throughput. The results show the expected dependence of FRD on input angle and bend radius, reveal comparatively weak sensitivity to externally applied compressive loading under the investigated conditions, and identify a reproducible periodic dependence on fiber twist angle. In addition, relative throughput measurements indicate that the reduction in relative throughput with increasing input angle cannot be explained solely by a simple projected-area model. The automated workflow and scalability of the system provide a versatile framework for the large-scale characterization of optical fibers required by next-generation spectroscopic survey facilities.
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All authors Daksh Singh, Ting S. Li, Sarik Jerma, Shaojie Chen
Quantum Physics
Noisy Quantum Query Complexity via Fractional Block Sensitivity
Mehil Agarwal, Shravas Rao and Fang Song
We study
quantum query complexity under several models of imperfect oracle access, and develop lower bounds through a common framework based on fractional block sensitivity ($\operatorname{fbs}$). For a negligent oracle that applies the correct query with probability $1-p$, we prove a lower bound in terms of $\operatorname{fbs}(f,0^n)$. We also show, perhaps surprisingly, that negligence need not destroy
quantum speedups: any function $f$ can be transformed into a partial function $f'$ whose negligent query complexity essentially preserves the
quantum query complexity of $f$. This gives partial functions with exponential
quantum speedups even under negligent queries, and in particular rules out a general lower bound in terms of $\operatorname{fbs}(f)$ for partial functions in this model. For two other models, we obtain general lower bounds in terms of $\operatorname{fbs}(f)$ for all Boolean functions. For hybrid
algorithms using $Q$ coherent and $C$ classical queries, we prove the tradeoff $C+Q^2=\Omega(\operatorname{fbs}(f))$. For an IID dephasing noisy model where each query dephases the query-index register at rate $p$ independently, we prove $\Omega\!\left(p\,\operatorname{fbs}(f)\right)$ queries are necessary. Finally, we introduce a broader family of time-varying dephasing models and identify a variational resource that is always lower bounded by $\operatorname{fbs}(f)$. Computing this resource reduces to a convex optimization problem, providing a simple way to derive lower bounds for new noise schedules. As applications, we recover the hybrid and IID dephasing bounds and determine the query complexity of unstructured search when the dephasing rate grows over time.
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Quantum Physics
Walshness: an intrinsic neural-network representability metric for quantum states
Nisarga Paul, Kehuang Chen, Jessica K. Jiang et al. (+2 more)
Neural
quantum states (NQS) have emerged as powerful representations of
quantum states with rapidly expanding applications across
quantum many-body physics. Yet our understanding of when neural networks can efficiently represent physical
quantum states remains limited, in part due to the nonlinear parameterization of NQS, the intricate sign structure of
quantum states, and the sensitive dependence on basis choice. We introduce Walshness, a complexity metric of a
quantum state which quantifies whether it admits a compact neural-network representation. We rigorously prove that a general
quantum many-body state admits an efficient NQS representation if and only if it has bounded Walshness for various NQS architectures. We provide an
algorithm for finding the optimal basis by minimizing the energy of a corresponding classical
spin model. This allows us to empirically improve the learnability of various physical
quantum states, including ground states of the transverse-field Ising model and mixed-field toric code, often reducing infidelity by orders of magnitude, and recovers and generalizes the basis choice given by the well-known Marshall sign rule in frustrated antiferromagnets. Our results provide an intrinsic complexity metric for
quantum states with provable connections to their neural-network representability.
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All authors Nisarga Paul, Kehuang Chen, Jessica K. Jiang, Haimeng Zhao, Di Luo
Quantum Physics
Graph Neural Post-selection for Quantum Error Correction
Conor Carty, Tamas Noszko, Joschka Roffe et al. (+1 more)
Post-selection improves the logical reliability of
quantum computation by rejecting shots which are likely to result in logical failure. We introduce graph neural networks that predict decoder failure without additional decoder executions, using only syndromes, and for high-rate
quantum low-density parity-check (qLDPC) codes, existing belief-propagation posteriors. We evaluate rotated surface and bivariate bicycle (BB) code
memories under uniform depolarising
circuit-level noise. Retaining 90% of shots gives approximately 3700x and 740x reductions in logical error rates for [[72,12,6]] and [[144,12,12]] BB codes at realistic physical error rates. For the distance 5 surface code at physical noise p=0.003, our neural post-selector achieves logical error suppression comparable to the leading complementary gap method without running the decoder.
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All authors Conor Carty, Tamas Noszko, Joschka Roffe, Roberto Bondesan
General Relativity and Quantum Cosmology
Black hole sensitivity in Einstein–aether theory
Morgan Kidnew, Andrew Kovachik and Sergey Sibiryakov
We numerically find the solutions for slowly moving Schwarzschild black holes in Einstein–aether theory. We use these solutions to compute the sensitivity parameter which describes the coupling of the black hole to the aether field within point-particle effective theory. A simple analytic approximation for the dependence of the sensitivity on the Einstein–aether parameters is derived.
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Quantum Physics
Quantum Algorithms for OPI Variants Beyond Locality and Classical Decodability
Seyoon Ragavan and Noah Shutty
Regev's reduction quantumly finds codewords satisfying nonlinear constraints by decoding the dual code. To date, applications that have not been dequantized have relied on efficient classical decoders and coordinate-wise constraints. We overcome these restrictions separately. Our first contribution uses a
quantum decoder to find solutions $\mathbf{y}\in(\mathbb{F}_q\setminus\{0\})^m$ to $\mathbf{B}\mathbf{y}=0$, where $\mathbf{B}\in\mathbb{F}_q^{n\times m}$. For fixed
prime $q>2$, Chen, Liu, and Zhandry solve this problem for random
matrices with $m=\Omega(n^2)$, a regime now covered by classical
algorithms. We adapt their template to codes (spanned by the rows of $\mathbf{B}$) that satisfy a "two-fold multiplication property": the coordinate-wise products of pairs of codewords span a space of dimension smaller than $m$. Under suitable distance conditions, this allows us to solve instances with $m\leq n^{2-\Omega(1)}$, beyond the established guarantees of classical
algorithms. We also give an efficient classical
algorithm under a stronger three-fold multiplication property, leaving intermediate regimes as candidates for
quantum advantage. For Reed-Muller codes punctured at random points, our
algorithm finds a word in the unpunctured dual code supported exactly on those points. This works beyond known efficient classical decoding regimes. Our second contribution retains classical decoding but allows global constraints on symbol frequencies. We study "histogram-local" constraints, which specify the allowed numbers of occurrences of each symbol. For broad families, stability under resampling one coordinate yields efficient
quantum algorithms for variants of optimal
polynomial intersection (OPI) combining coordinate-wise and histogram-local constraints. Adapting Yamakawa-Zhandry, we prove a
quantum-classical separation for these problems relative to a classical random oracle.
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Materials Science
Orbital angular momentum in crystalline solids: non-equilibrium theory
Sangeeta Sharma, Peter Elliott and Samuel Shallcross
We develop a general operator theory of orbital angular momentum (OAM) in periodic solids that applies equally to
equilibrium and coherently driven states. Employing the
crystal momentum representation of Adams and Blount, we construct a periodic-solid OAM operator exactly corresponding to the symmetrized $\hat{\mathbf r}\times\hat{\mathbf v}$ observable, and show that it separates into local circulation (LC) and itinerant circulation (IC) sectors that are Hermitian and $U(1)$, and more generally $U(N)$, gauge covariant. In
equilibrium, the LC and IC sectors reduce to the established modern theory of orbital magnetism; out of
equilibrium, the same operator structure exposes new contributions generated by
laser-written momentum-space textures and interband coherence. Applied to gapped
graphene, we uncover a rich phenomenology of ultrafast non-
equilibrium orbital angular momentum, including a quasi-stationary light-induced OAM. This latter finding, underpinned by a close connection between band-
manifold phase texture and nonequilibrium OAM, points towards new possibilities for light control over OAM in solids as well as a potentially rich role for topological band structures in designed OAM materials.
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High Energy Astrophysical Phenomena
A Multi-Wavelength Picture of the Surprisingly Short 2024/25 Outburst from EXO 0748-676
Amy H. Knight, Lauren Rhodes, Noel Castro Segura et al. (+11 more)
After sixteen years in quiescence, EXO 0748-676 unexpectedly returned to outburst in March 2024. However, in stark contrast to its previous outburst (1985 - 2008), EXO 0748-676 returned to quiescence in January 2025, after ~ 10 months in outburst. Here, we collate data from nine observing facilities, covering wavelengths from
radio to X-ray, to provide the first multi-wavelength study of the 2024/25 outburst. Unlike the 1985 outburst, both the rise and decay are fully captured at X-ray and optical wavelengths. The light curves do not exhibit the hallmarks of a canonical transient low-mass X-ray binary outburst. Instead, the X-ray and optical fluxes remain reasonably stable during the 2024/25 outburst. The wealth of optical data of EXO 0748-676 reveals a skewed optical phase curve and an irradiation-dominated optical light curve which lasts until the onset of hydrogen recombination in the outer disc at ~11000K, triggering a rapid fade at the end of the outburst. X-ray observations by XMM-Newton and NICER revealed that EXO 0748-676 was heavily obscured early on, with spectra exhibiting a dampened soft X-ray contribution. We find that a spectral model including a clumpy, ionised absorber describes the obscuration, although the exact cause of the early-time obscuration remains uncertain. X-ray colour analysis indicates that EXO 0748-676 spent most of the ~10 month outburst in a faint, hard state. EXO 0748-676 increased marginally in brightness towards the end of the outburst, but never entered a soft spectral state. This behaviour is characteristic of a failed transition outburst.
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All authors Amy H. Knight, Lauren Rhodes, Noel Castro Segura, Douglas J. K. Buisson, Aru Beri, David M. Russell, Kevin Alabarta, Maria C. Baglio, Jakob van den Eijnden, Matthew J. Middleton, Payaswini Saikia, Chris Done, Rob Fender, Fraser Lewis
Quantum Physics
Causal Trade-Offs in Superluminal Extensions of Relativity. A no-go theorem
Amrapali Sen, Matthias Salzger and V. Vilasini
Extensions of relativity that include superluminal reference frames have recently been proposed by Dragan and Ekert as a way to reconcile relativistic
symmetry with
quantum uncertainty. In this work, we develop a causal modelling framework to formally study this proposal and prove a no-go
theorem demonstrating that a theory permitting superluminal reference frames can avoid superluminal signalling only if it severely constrains which spacetime regions are accessible to operational protocols, if the choice of reference frame has observable consequences or if free variables do not exist or their existence depends on the reference frame. Crucially, our result goes beyond the familiar intuition that superluminal transformations may lead to superluminal signalling; our no-go result shows that Dragan and Ekert's proposal of introducing objective uncertainty does not, by itself, eliminate this conflict. In fact, because superluminal signalling might instead be avoided by relaxing other fundamental assumptions in the presence of superluminal reference frames, the proposed objective uncertainty may not be necessary at all. Our results clarify the limitations of uncertainty-based resolutions and the causal trade-offs faced by superluminal extensions of relativity.
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High Energy Physics (Theory) · Cross-listed from math.AG
Supermoduli spaces are non-projected in every genus $g\geq 3$
Mauricio Corrêa, Ron Donagi and Simone Noja
We prove that, for every genus $g\geq 3$, the primary obstruction of each parity component of the
moduli superstack of smooth unpunctured super Riemann surfaces is nonzero, both algebraically and holomorphically. Consequently, both components are non-projected and, in particular, non-split: neither admits an algebraic or holomorphic retraction onto its reduced
moduli stack of
spin curves.
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Superconductivity
Electronic structure and two-orbital model of the quadlayer La$_5$Ni$_4$O$_{13}$
Jian-Xiang Sun, Haokan Xiao, Cui-Qun Chen et al. (+1 more)
The discovery of pressure-induced superconductivity in Ruddlesden–Popper (RP) nickelates has stimulated extensive interest in high-T$_c$
superconductors. Here, we systematically study the electronic properties of the quadlayer RP nickelate La$_5$Ni$_4$O$_{13}$ under ambient pressure, 5% isotropic compressive strain, and 4% $c$-axis uniaxial strain using density functional theory (DFT) and random phase approximation (RPA) calculations. DFT calculations show that isotropic strain broadens the Ni-$e_g$ bands and induces charge transfer from O-$p$ to Ni-$d$ orbitals, whereas $c$-axis uniaxial strain selectively shifts the $d_{z^2}$-derived bonding1 band upward while leaving the $d_{x^2-y^2}$ dispersion nearly unchanged. From Wannier downfolding, we construct a quadlayer two-orbital model that reproduces the low-energy Ni-$e_g$ bands. Our model reveals that under ambient pressure and 5% isotropic strain, the
Fermi surface consists of two electron pockets ($\alpha$ and $\delta$) and three hole pockets ($\beta$, $\beta^{\prime}$, and $\beta^{\prime \prime}$), while under uniaxial strain, a $\gamma$ hole pocket with $d_{z^2}$ orbital character emerges. RPA calculations reveal that the leading
spin response shifts from $\mathbf{q}\approx(2\pi/3,2\pi/3)$ at ambient pressure to $\mathbf{q}\approx(\pi,\pi)$ under both strain conditions and is enhanced under $c$-axis compression. These results suggest that $c$-axis compression may provide a favorable route to superconductivity in the quadlayer nickelate analogous to that in
bilayer and trilayer nickelates.
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All authors Jian-Xiang Sun, Haokan Xiao, Cui-Qun Chen, Dao-Xin Yao
High Energy Physics (Phenomenology)
A massive right-handed sterile neutrino in three-body ${\bar B}\to D^*\ell^-{\bar N}_R$ decays - a Monte Carlo simulation study
Bhubanjyoti Bhattacharya, Thomas E. Browder, Lucien M. Cremaldi et al. (+6 more)
We investigate the differential decay distributions of $\bar{B}\to D^*\ell^-{\bar N}_R $, where $N_R$ is a heavy right-handed
neutrino (RHN) and $\ell = e, \mu$. We employ a newly developed Monte Carlo event generator based on the EvtGen framework that can simulate beyond-the-Standard-Model processes. We validate the implementation of the model by comparing the Monte-Carlo results with analytical results for several kinematic variables such as $q^2$ and missing mass, as well as signatures in the angular distributions such as $A_{FB}$, $S_{3}$, $S_{5}$, etc. This MC Generator will enable new experimental searches for RHNs. We discuss the sensitivity of various observables to the presence of an RHN and the feasibility of an experimental analysis at Belle II.
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All authors Bhubanjyoti Bhattacharya, Thomas E. Browder, Lucien M. Cremaldi, Horacio Crotte Ledesma, Nilakshi Das, Alakabha Datta, Tejhas Kapoor, Kumar Pandey, Alexei Sibidanov
High Energy Physics (Theory)
Gaugino condensates in $\mathcal{N}=1$ super-Yang-Mills Theory on Eguchi-Hanson space
Mohamed M. Anber
We study gaugino condensates in $\mathcal{N}=1$ $SU(N)$ super-Yang–Mills theory on Eguchi–Hanson space using instanton methods. Fractional topological charge and the spectral asymmetry of the asymptotic $\mathbb{RP}^3$ boundary modify the instanton calculus. A charge-$\frac12$ instanton carries only two adjoint gaugino zero modes and can therefore contribute directly to the bilinear. Because the Eguchi–Hanson path integral prepares a boundary state on $\mathbb{RP}^3$, the observables are boundary-sector-projected amplitudes. Moreover, supersymmetric Ward identities ensure that
chiral correlators are independent of insertion points and the Eguchi–Hanson resolution parameter. For $SU(2)$ instanton, with central holonomy, the full collective-coordinate integral gives $\langle\operatorname{tr}(\lambda\lambda)\rangle=16\pi^2\Lambda^3$ for a specified boundary projection, reproducing the flat-space value. For a single $SU(2)$-block
embedding in $SU(N>2)$, the noncentral holonomy requires a continuum determinant for renormalization-group invariance, so zero modes alone do not determine the bilinear. We also study a charge-$1$ $SU(4)$ two-block saddle with central holonomy, $16$ bosonic
moduli, and $8$ adjoint zero modes. Its collective-coordinate integral gives $\langle\prod_{i=1}^4\operatorname{tr}(\lambda\lambda)(x_i)\rangle=\frac16(16\pi^2\Lambda^3)^4$. Under the assumptions required for position independence and clustering, this result determines the fourth power of the bilinear condensate in the corresponding boundary sector. Since no independent bilinear calculation is available in the same sector, the factor $1/6$ does not by itself constitute a clustering puzzle.
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Cosmology and Nongalactic Astrophysics
Anna D'Ambrosio and Matteo Viel
Introducing
primordial magnetic fields (PMFs) into the standard cosmological model, $\Lambda$CDM, has an impact on the matter power spectrum at the linear level, resulting in an increase of power on small scales. In this work, we use the enhanced spectrum as the initial condition for dark-matter-only N-body simulations and study its non-linear
evolution. From the resulting non-linear matter power spectrum, we calculate the convergence power spectrum of weak
lensing ($C_{\kappa}$) and show how the presence of PMFs causes an enhancement at high multipoles. We then construct an emulator for $C_{\kappa}$ that also includes intrinsic
alignment and
baryon feedback. We perform MCMC analyses using mock data generated for different PMF models and for three values of the maximum multipole, $\ell_{\rm max}=5000$, $10000$, and $20000$. The PMFs models are characterized by the two parameters that define the power-law power spectrum of the
magnetic field $P_B(k)\propto B_{\rm 1Mpc}^2 k^{n_B}$, where $B_{\rm 1Mpc}$ is the amplitude at a scale of $1$ Mpc and $n_B$ is the power spectral index. For $\Lambda$CDM mocks, corresponding to $B_{\rm 1Mpc}=0$, we obtain approximate upper limits of $B_{\rm 1Mpc}<1.6$, $1.0$, and $0.8\,{\rm nG}$ at the $95\%$ confidence level for the three values of $\ell_{\rm max}$ respectively. For non-zero input
magnetic fields, the recovery of $B_{\rm 1Mpc}$ and $n_B$ depends strongly on the PMFs model and on the maximum multipole considered. Models with $n_B=-2.1$ are more easily constrained than models with $n_B=-2.7$, since they produce a stronger enhancement of the convergence power spectrum. We find no clear degeneracy between the PMFs parameters and the intrinsic
alignment or
baryon feedback parameters, while $B_{\rm 1Mpc}$ and $n_B$ can be degenerate. We characterize this degeneracy through linear fits to selected $2$D posterior distributions.
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High Energy Physics (Phenomenology)
Glueballs and fractional anomalous determinants at nonzero $\theta$, and the decays of the X(2370)
Francesco Giacosa, Shahriyar Jafarzade, Győző Kovács et al. (+3 more)
Using fractional anomalous determinants, we construct a model of the trace and axial anomalies of a $SU(3)$ gauge theory at nonzero $\theta$ angle through the couplings to scalar and pseudoscalar glueballs. In the pure gauge theory, we reproduce the $\theta$ dependence of the
vacuum energy and the scalar-glueball mass from the
lattice, and estimate the jump in the topological charge density for the first-order transition at $\theta = \pi$. In QCD, the coupling of a pseudoscalar glueball to fractional anomalous determinants describes all of the four three-pseudoscalar decay channels of the $0^{-+}$ glueball candidate $X(2370)$ measured by the BESIII collaboration. Measuring the decay rates for $\eta \eta \eta$ and $\eta \eta \eta'$ can provide a stringent test of the model.
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All authors Francesco Giacosa, Shahriyar Jafarzade, Győző Kovács, Péter Kovács, Robert D. Pisarski, Fabian Rennecke
High Energy Physics (Theory)
Twisted BPS decoupling limits and AdS/CFT
Troels Harmark
BPS decoupling limits of string and M-theory have led to profound insights into
gravity and non-perturbative
quantum theory, most notably with the AdS/CFT correspondence. In this paper, we initiate the study of twisted BPS decoupling limits, in which the relevant BPS states carry momentum along circle fibers geometrically twisted over a base space.
Prime examples are found in type IIB string theory on AdS$_5\times S^5$, for which the twisted limits involve the BPS states of the global
symmetry algebra PSU$(2,2|4)$. In general, string fluctuations in a twisted BPS decoupling limit are described by non-relativistic sigma-models on emergent non-Lorentzian target spaces with a natural
symplectic structure. This further supports the broader connection between BPS limits and non-Lorentzian geometry. We introduce analogous limits of D-branes as well, probing the same
symplectic structure as the string. For AdS$_5\times S^5$, twisted BPS decoupling limits are dual to
Spin Matrix theory limits of $\mathcal{N}=4$ supersymmetric Yang-Mills theory, providing tractable and explicit
quantum-mechanical descriptions of non-perturbative regimes of AdS/CFT.
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