Instrumentation and Methods for Astrophysics
Gestalt: a meta-foundation model for astronomy
Michael J. Smith and Shashwat Sourav
The Platonic Representation Hypothesis predicts that sufficiently scaled foundation models converge on a shared representation of the world. As each non-converged model gives a noisy view of a common structure when passed the same input, we ask whether we can combine models into a representation that outperforms its individual components. We test this on
galaxies: we embed images via a basket of 22 frozen foundation models from eight families, whiten each view, and take a randomised SVD of the
embedding concatenation. The resulting 1024-dimensional
embedding outperforms every basket member on 19/21 of our tested metrics for physical property and
galaxy morphology estimation for HSC, JWST, and DESI Legacy Survey imagery. We find that performance rises with basket size and basket architectural diversity, and that the meta-foundation model's performance transfers across astronomical surveys. We conclude that a useful astronomical foundation model can be assembled from existing generalist models with no training required beyond a single unsupervised projection. By leveraging the community's already-spent work, we save a lot of compute: a fresh pre-train of a comparable single-domain model would cost $\mathcal{O}(10^{4}$–$10^{5})$ A100 GPU hours (emitting several tonnes of CO$_2$eq.), whereas assembling Gestalt requires minutes on a single machine.
Read the full abstract ▾
High Energy Physics (Theory)
A New Approach to Black Hole Thermodynamics in General EMD-like Theories
Peng-Yu Wu and H. Lu
We consider general EMD-like theories involving arbitrary numbers of both Maxwell fields and dilatonic scalars. We study charged black holes and derive several algebraic and differential relations among the thermodynamic quantities, scalar charges and the non-extremal parameter. These allow us to obtain two sets of master equations of thermodynamic quantities, depending on the choice of basic variables parameterizing the system. Solutions to either set of the master equations give rise to all the thermodynamic quantities, without constructing black hole solutions. We obtain all the thermodynamic quantities perturbatively in the power series expansions of charges, which we then verify using perturbative black hole solutions up to and including the quartic order in charges.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Testing Offsets Between Cluster-Scale Halos and BCGs in Strong Lensing Models Using the Jackknife Method
Sangjun Cha, Marceau Limousin and M. James Jee
Offsets between cluster-scale dark matter
halos and brightest cluster
galaxies (BCGs) inferred from strong
lensing (SL) models have been used to investigate cluster dynamics and dark matter physics. However, it is necessary to test whether these offsets are required by SL data themselves. We investigate whether allowing these offsets improves predictive accuracy and examine the effects on magnification, time-delay predictions, and critical curve positions. We evaluate lens models of Abell 370, RX J1347.5-1145, and MACS J0416.1-2403 using the jackknife method, which assesses predictions for source systems excluded from the lens reconstruction. Models are constructed with MrMARTIAN, which combines analytic mass profiles with a regularized grid that represents mass structure not captured by the profiles. We compare fixed and free
halo position models across regularization weights. The root mean square values averaged over excluded systems agree within bootstrap uncertainties, while the median paired differences remain close to zero across all three clusters and tested regularization weights. These results indicate comparable predictive accuracy between the fixed and free models. The total mass distributions remain broadly similar, although the magnitudes of fitted
halo offsets vary with regularization, showing that the mass decomposition is not unique. For these three clusters, offsets between BCGs and cluster-scale
halos in the lens models are not required by the SL data to improve predictive accuracy within the MrMARTIAN framework. The mass decomposition between the regularized grid and cluster-scale
halos is not uniquely determined. These findings limit physical interpretations based on fitted
halo positions alone. The model dependence of magnification and time-delay estimation can also affect the inferred intrinsic properties of high-
redshift sources or the Hubble constant.
Read the full abstract ▾
High Energy Physics (Phenomenology)
Searching for BSM Experimental Signatures with Large Lagrangian Models
Ibrahim Elsharkawy, Victoria Knapp-Perez, Wahid Bhimji et al. (+1 more)
The search for physics Beyond the Standard Model (BSM) is generally limited not by the supply of theory descriptions but by the lack of discriminating experimental observations. A case in point is dark matter, where the overwhelming gravitational evidence only goes so far in distinguishing between models within a vast theory space. Exploring the space of testable model signatures may help identify overlooked experimental observables and indicate the utility of future experiments. A challenge is designing a search through model signatures outside what is found in the literature. Our primary contribution is hAIthem, a framework that combines the self-guided exploration of reinforcement learning (RL) with the broad literature-derived knowledge of LLMs. We build an RL
agent that learns to find which portions of a theory's high-dimensional parameter space are not excluded under some subset of constraints by playing a Battleship-style "game" against a suite of phenomenology tools. The
agent is built as a Large Lagrangian Model (LLaM), an autoregressive
transformer that reads a tokenized Lagrangian, is pretrained at scale (here on ~1 billion
tokens from ~10,000 Lagrangians), and is fine-tuned in a live environment. The framework then constructs a decision tree that separates RL-found regions using observables computed with established tools, and passes the remaining degenerate regions to a set of LLM
agents that compete to produce realistic signatures. In this proof of concept, RL-search outperforms an evolutionary-
algorithm baseline, finding more viable regions with greater physical diversity. In a restricted space of single dark scalar multiplet models, we find that hAIthem proposes interesting combinations of previously studied observables, such as the application of a
halo-independent kinematic ratio to paleo-detectors.
Read the full abstract ▾
All authors Ibrahim Elsharkawy, Victoria Knapp-Perez, Wahid Bhimji, Aishik Ghosh
High Energy Physics (Theory)
Bootstrapping Weakly Broken Gauge Theories in (A)dS
Daniel Baumann, Kurt Hinterbichler, Callum R. T. Jones et al. (+1 more)
We develop a bootstrap approach for weakly broken gauge theories in (anti-)de Sitter space, focusing on cases in which the conservation of the dual boundary current is broken by a double-trace operator. Integrating the corresponding Ward identity, we derive pseudo-charge conservation identities that contain fixed nonlocal contributions as integrals of three-point functions. These identities impose consistency conditions on the space of allowed theories. As an illustrative example, we study Yang-Mills theory in AdS with
symmetry-breaking boundary conditions for charged matter and show that the pseudo-charge conservation identities constrain the mixing between the two quantization sectors. We then apply the framework to the
Higgs mechanism for
gravity in two AdS spaces with a common boundary, coupled so that the corresponding stress tensors are not separately conserved. In this setting, the ordinary charge conservation identities recover the factorization into two independent CFTs, whereas the pseudo-charge conservation identities hold for arbitrary values of the
symmetry-breaking parameter. Finally, for conformal
gravity in de Sitter space, we constrain the interactions between the graviton and the partially massless
spin-2 field, both in the minimal theory and in the presence of additional scalar or vector matter, finding agreement with the predictions of the corresponding bulk theories.
Read the full abstract ▾
All authors Daniel Baumann, Kurt Hinterbichler, Callum R. T. Jones, Nathan Meurrens
High Energy Physics (Theory)
Quantum Gravity Principles for 4d $\mathcal{N}=2$ Supergravity Theories and Asymptotic Hodge Theory
Lukas Kaufmann and Timo Weigand
We study the behaviour of general four-dimensional N=2 supergravity theories near boundaries at infinity of the vector multiplet
moduli space, with a focus on a clear distinction between properties that follow from supergravity alone rather than from a consistent UV completion in
quantum gravity. The basis for our analysis is the appearance of a real variation of polarised Hodge structure governing the vector multiplet
moduli space of N=2 supergravity, combined with very recent advances in the mathematics literature. The resulting classification of infinite distance degenerations exactly agrees, at the level of gauge couplings, with a possible interpretation of the limits as decompactification limits to five or six dimensions or as weakly coupled string limits, as expected from a
quantum gravity perspective. This observation extends previous results found in the context of string compactifications on Calabi–Yau varieties and, remarkably, holds for general four-dimensional N=2 supergravity theories regardless of a UV completion. We furthermore show the existence of a Kähler basis in which the triple couplings of the prepotential are non-negative, irrespective of a
geometric origin of the supergravity theory. Finally we propose two non-trivial constraints for a four-dimensional N=2 supergravity to be compatible with
quantum gravity: Integrality of the Hodge structure as a necessary condition for the completeness hypothesis and the existence of a simple normal crossing compactification of the
moduli space to ensure compatibility of the weakly coupled asymptotic gravitational duality frames.
Read the full abstract ▾
Quantum Physics
Making the most of leftovers: Improved privacy amplification for quantum key distribution
Matthew Simon Tan, Bartosz Regula and Marco Tomamichel
The amount of secret key that can be obtained from a
quantum key distribution run depends on both the physically observed error rates and the mathematical bounds used to certify security. For finite
datasets, conservative bounds force users to discard a substantial fraction of the potentially available key. Here we further refine and extend the
privacy amplification bounds achievable through the recent leftover hash lemma of Regula and Tomamichel [arXiv:2603.04493] and incorporate them into the security analysis of
quantum key distribution based on entropic uncertainty relations. This improves on state-of-the-art key rates in finite-block regimes, certifying more secret key from the same experimental data without changes to the protocol, and outperforming techniques based on
entropy accumulation. The results illustrate how sharper mathematical estimates can directly increase the usable output of a
quantum communication system.
Read the full abstract ▾
Cosmology and Nongalactic Astrophysics
Close Pulsar Pairs See Dark Matter Substructure through the Gravitational-Wave Background
Abhiram Cherukupalli, Vincent S. H. Lee, Kim V. Berghaus et al. (+1 more)
Pulsar timing arrays detect signals from dark matter substructure, but a nanohertz gravitational-wave background (GWB) severely degrades their sensitivity. We show that timing
pulsar pairs separated by sub-parsec distances avoids this degradation. The GWB imprints nearly the same perturbation on both
pulsars and is suppressed in the difference of their residuals, whereas a nearby dark matter subhalo perturbs the two differently and survives. We find that an array with
pulsar pairs separated by $0.1\,\mathrm{pc}$ improves the sensitivity to subhalos of order $\sim10^{-6}$
solar masses by more than an order of magnitude, relative to an otherwise identical array of widely separated
pulsars. Dense globular clusters naturally host many such pairs, though the baryonic environment must be separated from a dark matter substructure signal.
Read the full abstract ▾
All authors Abhiram Cherukupalli, Vincent S. H. Lee, Kim V. Berghaus, Kathryn M. Zurek
High Energy Astrophysical Phenomena
Nearby Supernova Science in the Era of High Cadence, Deep Time Domain Surveys
David J. Sand, Bhagya Subrayan, Conor L. Ransome et al. (+41 more)
We discuss science opportunities for nearby
supernovae (SNe) in the era of the Vera C. Rubin Observatory's Legacy Survey of Space and Time (LSST), emphasizing the youngest phases of SN
evolution and the value of contemporaneous high-cadence shadowing surveys. LSST's Wide Fast Deep survey will discover enormous numbers of SNe, but its $\sim 3$ day cadence will miss signatures that evolve on timescales of hours to days, requiring cadence augmentation by other programs. We present simple depth and cadence metrics for early SN signatures and use empirical nearby SN discovery rates to estimate the resulting science opportunities. LSST will detect or set limits on precursor emission from hundreds of core-collapse SNe, including $\gtrsim 50$-100 Type IIn and normal Type II SNe annually, as well as $\gtrsim$5 Type Ibn. Within $\sim 200$ Mpc, roughly 250 Type Ia SNe are classified annually, providing the potential to identify hundreds of early light-curve excesses, and a robust measurement of the incidence of extreme high-velocity features ($>$25,000 km s$^{-1}$). A shadowing survey with a depth of $\sim 22.5$ mag could search for early light-curve features, akin to the light-curve excess seen in SN2023ixf, across dozens of nearby core-collapse SNe every year. Rapid spectroscopy of $\gtrsim$150 Type II SNe per year within $\sim$160 Mpc could constrain the incidence of short-lived flash features to $\lesssim$10% within a few years, while also tying this to the rate of precursor emission in normal Type II SNe. We also discuss the challenges posed by early classification ambiguity and faint nonterminal transients, and we request that the 80 hour embargo on LSST images be waived for nearby
galaxy fields. Finally, we advocate for a Nearby
Galaxy Transient Broker that integrates transient streams, archival data, forced photometry, and follow-up triggering in a single platform.
Read the full abstract ▾
All authors David J. Sand, Bhagya Subrayan, Conor L. Ransome, Griffin Hosseinzadeh, K. Azalee Bostroem, Jennifer E. Andrews, Jeniveve Pearson, Yize Dong, Stefano Valenti, Saurabh W. Jha, Brian Hsu, Aravind P. Ravi, Manisha Shrestha, Charles D. Kilpatrick, Noah Franz, Mojgan Aghakhanloo, Igor Andreoni, Moira Andrews, Katie Auchettl, Federica B. Bianco, Régis Cartier, Siddharth Chaini, Diva Chaudhary, Analía V. Smith Castelli, Shar Daniels, Alexei V. Filippenko, Melissa L. Graham, Xander J. Hall, Daichi Hiramatsu, D. Andrew Howell, Lindsey A. Kwok, Amanda R. Lopes, Thomas Matheson, Curtis McCully, Maryam Modjaz, Phillip Noel, Gregory S. H. Paek, Antonella Palmese, Anthony L. Piro, Monika Soraisam, Sergiy Vasylyev, József Vinkó, J. Craig Wheeler, Samuel D. Wyatt
General Relativity and Quantum Cosmology
A Strong Cosmologically Coupled Mass Growth Solution in Linearized General Relativity
Kevin S. Croker, Joshua Cohon, Viktor T. Toth et al. (+13 more)
DESI Data Release 2 has heightened interest in cosmologically coupled black holes (CCBHs) as an explanation for accelerating late-time expansion, but known models for CCBHs grow too slowly to drive it. We construct at linear order a solution to General Relativity whose Hernandez-Misner-Sharp mass passively grows $\propto a^\kappa$ as the universe expands. The constant $\kappa$ enters all
eigenvalues of the Weyl and stress-tensor operators, so growth is unambiguously physical in both free-field and material sectors. The solution is causal over spacetime relevant for
stellar collapse compact objects. A cloud of energized
vacuum emerges at $\kappa = 3$, complementing the $a^3$ scaling predicted elsewhere for the masses of energized
vacuum black holes. This first step toward $\kappa \sim 3$ CCBH exact solutions enables observational tests with
pulsar binaries.
Read the full abstract ▾
All authors Kevin S. Croker, Joshua Cohon, Viktor T. Toth, Massimiliano Rinaldi, Nicolas Fernandez, Joel L. Weiner, Duncan Farrah, Gregory Tarlé, Gustavo Niz, Christopher Cain, James W. Rohlf, Alejandro Aviles, Jake Summers, Leander Thiele, Rogier A. Windhorst, Joshua Grumski-Flores
High Energy Physics (Theory)
Scale-Covariant Holography
Nikolay Bobev, Pieter Bomans and Fridrik Freyr Gautason
We explore a vast landscape of scale-covariant string backgrounds that arise from the backreaction of D$p$-branes. In a convenient Weyl frame the metric has an AdS factor and the dilaton has a non-trivial profile. This structure provides a notion of scale covariance that facilitates a
holographic analysis and provides a window into the dynamics of the dual strongly coupled non-conformal gauge theory. We present different classes of supergravity solutions of this kind and discuss their dual field theory interpretation. We find several new supersymmetric backgrounds arising from D2-branes by utilizing four-dimensional gauged supergravity, D$p$-branes wrapped on compact
manifolds, and infinite families constructed directly in ten dimensions. We construct
holographic RG flows between some of the new supersymmetric backgrounds and compute the spectrum of low-lying local operators. Holography determines the form of observables such as the thermal free energy and scalar two-point functions, predictions which could be tested on the
lattice.
Read the full abstract ▾
High Energy Physics (Theory)
Detectors in Nonrelativistic Conformal Field Theories
Cyuan-Han Chang, Subham Dutta Chowdhury, Ian Moult et al. (+1 more)
Correlations in asymptotic fluxes provide one of the primary experimental means of studying physical systems. In the context of relativistic QFT, the formalization of such experiments in terms of detector operators has led to significant progress. Motivated by these successes, in this paper we initiate a study of detector operators in nonrelativistic conformal field theories (NRCFTs). In NRCFTs, fluxes are distributed in both angle and velocity, making the natural detector operator the energy flux differential in velocity, $\mathcal{E}_v(\hat{n})$. We provide non-perturbative definitions of these operators in NRCFTs, and study their
symmetries and
algebra. We calculate one-point functions of these detector observables in a variety of few and many body states of representative NRCFTs, including free
fermions, as well as
fermions at unitarity. In interacting three-body states, they exhibit a remarkably rich behavior reflective of the Efimov three-body wave-function, including the formation of an enhanced "jet" structure due to the presence of resonant interactions. We use these detectors to derive a nonrelativistic generalization of the Hofman-Maldacena conformal
collider bounds by arguing for positivity of $\mathcal{E}_v(\hat{n})$, and imposing this in
spin 1 states. We outline a number of future directions for the study of detectors in NRCFTs, and discuss how they can be measured in a variety of experimental platforms from cold atoms to low energy
neutron experiments.
Read the full abstract ▾
All authors Cyuan-Han Chang, Subham Dutta Chowdhury, Ian Moult, Dam Thanh Son
Quantum Physics
Exact Operator Complexity Measures from Random Matchgate Unitaries
Gregory A. L. White, Jens Eisert and Neil Dowling
Matchgate
circuits describe classically tractable dynamics in a physically relevant setting while nonetheless exhibiting features characteristic of complex
quantum systems, such as high amounts of magic. This invites the broader question: to what extent are typical complexity measures saturated under trivial dynamics? Here, we address this by studying the behaviour of different Heisenberg-picture complexity measures in random matchgate ensembles. Our main technical contribution is a tractable and generalisible free-fermionic
unitary Weingarten calculus formulated entirely in the Majorana basis. This method is tailored to computing moments of operators, and simplifies to a combinatorics problem which depends on the boundary conditions prescribed by a given operator functional. Using this framework, we derive closed-form expressions for the typical local-operator
entanglement, operator stabiliser
entropy, and higher-order out-of-time-ordered correlators. For extensive initial Majorana strings, both operator
entanglement and stabiliser
entropy obey volume laws, even though the underlying
circuits remain classically simulable. Out-of-time-ordered correlators can likewise become exponentially small, showing that their late-time saturation value alone does not witness computational hardness and constituting a classically tractable example of emergent free independence. Finally, we relate these separations to operator resource theories, showing how operator
entanglement beyond the Gaussian baseline lower-bounds the number of non-Gaussian gates in doped matchgate
circuits. Our results present a practical toolbox for computing exact averages over random matchgates, while clarifying the distinction between
quantum resources versus simulation complexity, and their dependence on the representation being exploited.
Read the full abstract ▾
High Energy Astrophysical Phenomena
Not So Heavy Metal I: Low Metallicity Enhances the Rate of high-redshift Superluminous Supernovae
Ben Margalit, Allison L. Strom, Cristina Andrade et al. (+4 more)
Type-I superluminous
supernovae (SLSNe) are extremely luminous
stellar explosions originating from the core collapse of massive
stars. Unlike normal core-collapse
supernovae, however, SLSNe occur almost exclusively in metal-poor environments. As a result, their volumetric rate should not simply trace the
cosmic star-formation history, but instead evolve with the
metallicity distribution of
galaxies across
cosmic time. In this work, we introduce a new theoretical framework for modeling the volumetric rate of astrophysical sources as a function of
redshift and
metallicity. Our formalism combines
metallicity scaling relations,
stellar-mass distribution functions, and
metallicity-dependent production efficiencies. Importantly, it also distinguishes between
metallicity measures based on O/H and Fe/H abundances. Applying our new formalism to SLSNe, we predict volumetric rates that are nearly an order of magnitude higher at $z \gtrsim 2$ compared to models in which the rate traces the
cosmic star-formation rate alone. This has direct implications on the detection prospects of high-$z$ SLSNe with the Vera C. Rubin Observatory and other time-domain surveys.
Read the full abstract ▾
All authors Ben Margalit, Allison L. Strom, Cristina Andrade, Michael W. Coughlin, Adam A. Miller, Steve Schulze, Ved G. Shah
Quantum Physics · Cross-listed from math.HO
A unified interpretation of probability
Louis Vervoort
In this article I revisit the frequency interpretation of probability of von Mises, and argue that it contains the key elements of any coherent interpretation of scientific probability - notwithstanding the heavy criticisms von Mises collected from mathematicians and philosophers alike. I propose a modified definition that is not based on von Mises' "infinite collectives" but retains an essential ingredient of his interpretation, namely that probability can only quantitatively be defined for events that are, or can be, repeated in similar conditions and that exhibit frequency stabilisation. New is that the mentioned "conditions" should be "partitioned". Thus, I will partition probabilistic systems into object and environment, or in object, initiating, and probing subsystem, and show that such partitioning solves a series of classic problems. Other consistent interpretations can be unified with frequentism, e.g. Bayesianism à la Jaynes. I explore in detail the tantalising subjective or operationalist touch of probability, and argue that it can be put on objective grounds. One further upshot of the model is that several
quantum puzzles can be seen as deriving from an imprecise interpretation of probability.
Read the full abstract ▾
History and Philosophy of Physics
On Gauge Gravity's 'Hypermomentum Challenge' to the Geometric Trinity
Kartik Tiwari
Claims concerning a dynamical equivalence between general relativity and two reformulations of it, in which
gravity is encoded in torsion and non-metricity respectively, have attracted some
attention. If taken to be true, this '
Geometric Trinity' suggests that it is impossible to determine, even in principle, whether one inhabits a spacetime solution possessing
curvature, torsion or non-metricity (insofar as the probes of geometry are paths of test particles). This claim is in direct tension with the long tradition of studying
gravity as a gauge theory, in which distinct
geometric attributes couple to distinct properties of matter (such as energy-momentum to
curvature and
spin angular momentum to torsion). In this short paper, I compare these two conflicting frameworks for geometrizing spacetime and describe the precise source, nature and implications of their disagreement. The equivalence claim holds only under a substantive restriction on the matter sector, namely that matter does not couple to an independent affine connection. Because the relevant couplings remain beyond current empirical reach, the choice between the frameworks turns on a trade-off among ontological, epistemic, and methodological forms of parsimony.
Read the full abstract ▾
Physics and Society
Multiscale Renormalization of Weighted Networks
Mattia Marzi, Frank P. Pijpers and Diego Garlaschelli
Recent progress in network renormalization has identified various ways to transform network representations consistently across resolution levels. In particular, the renormalization flow describing how random graph models transform under node aggregation has identified a fixed point corresponding to an aggregation-invariant model that preserves the form of the connection probability across arbitrary scales. While this probabilistic multiscale approach has successfully been used to model real-world networks, construct latent-space node
embeddings, and reconstruct finer-grained versions of aggregate network data in a principled resolution-invariant way, it has so far been restricted to binary graphs. Here we reformulate multiscale network renormalization for weighted random graphs. Via a generating-function approach, we identify a weighted multiscale model whose full probability law, encoding both link creation and weight assignment, has an invariant compound-Poisson form under arbitrary node aggregation. The renormalization rules that transform parameters across aggregation levels allow the ensemble to be calibrated at one level and applied at another, enabling consistent modeling and reconstruction of weighted networks across arbitrary scales.
Read the full abstract ▾
Astrophysics of Galaxies
The orbital dynamics of the LMC and SMC about the Milky Way
Gurtina Besla and Nitya Kallivayalil
This review summarizes the changing observational and theoretical landscape that has led to rapid developments in our understanding of the orbital history of the Milky Way's most massive satellite
galaxies, the LMC and SMC. The determination of high precision center-of-mass proper motions for the Clouds and their environs, coupled with new insights into the structure of dark matter
halos from cosmological simulations, indicates that the Clouds are recent additions to the Milky Way's satellite system, where the LMC was sufficiently massive at infall to induce distortions in the Milky Way's dark matter
halo, and bring in satellites of its own. To gain insights into the orbital history of the Clouds it is, therefore, necessary to integrate orbits in a time evolving Milky Way and LMC potential. The proper motion measurements further indicate that the LMC and SMC have had a recent strong encounter with each other. This leaves open the impact of this encounter on their internal structures, and the degree of correspondence between their
stellar, HI and dark matter centers. The choice of kinematic center in turn affects the center of mass proper motions; this is the biggest observational unknown, even in the high precision
Gaia era. Given the expected mass loss of the SMC, the distortions it induces in the LMC
halo, and the recent LMC-SMC close encounter, understanding the orbits of objects about the LMC (including the SMC) and interpreting observational data of the Clouds requires full N-body simulations that are constrained by their present-day structure and kinematics.
Read the full abstract ▾
High Energy Physics (Theory)
Construction of mirror pairs of Berglund-Hubsch Calabi-Yau orbifolds of loop-type polynomials
Maxim Malyutin
In this paper, an
algorithm for constructing orbifolds of Calabi-Yau
manifolds of the Berglund-Hubsch-Krawitz (BHK) type and their mirror pairs for loop-type
polynomials is proposed and applied. A complete enumeration of loop
polynomials satisfying the Calabi-Yau condition was carried out, yielding 216 unique
polynomials. For each
polynomial, the Euler characteristics, the numbers of generations and singlets were computed, and the twisted sector states were analyzed using Roan's generalized combinatorial construction. It was established that Roan pairs are absent for all studied configurations, indicating a zero contribution of the twisted sectors to the difference in Hodge numbers upon resolving the orbifold singularities. The primary physical result of this work is the discovery of two configurations with diagonal exponents $\{74, 3, 3, 5, 3\}$ and $\{74, 3, 5, 3, 3\}$, for which the number of
quark and
lepton generations is precisely three ($N_{\text{gen}} = 3$), which is of key interest for constructing phenomenologically realistic models of particle physics.
Read the full abstract ▾
Materials Science
Accidental accuracy and formal consistency in $GW$+BSE: Exact benchmarks and regime-dependent error cancellation
Michael O. Atambo
Standard many-body perturbation theory for optical excitations combines the $GW$ approximation for quasiparticle energies with the Bethe-Salpeter equation (BSE) for the electron-hole response. Formally, the BSE kernel must equal the functional derivative of the self-energy, $K=\delta\Sigma/\delta G$. In routine practice, however, the kernel is built from a statically screened direct interaction and a bare exchange interaction, which breaks this consistency. Using exact diagonalization of the extended Hubbard dimer, we construct a controlled
benchmark that isolates the price of this inconsistency. We show that the internally inconsistent practical $GW$+BSE construction frequently yields accurate optical gaps through accidental cancellation between an underestimated $GW$ gap and an oversized bare-exchange kernel, and we map the regions of parameter space where this accidental accuracy occurs. Upon switching on the nearest-neighbor interaction and binding the
exciton, the practical construction remains the accurate one throughout the weak-binding regime, with cancellation optima at parts in $10^{3}$, while the frozen-$W$ construction fails at every binding strength. Beyond a binding threshold both static constructions deteriorate, showing that deeply bound
excitons require physics beyond any static kernel. Accidental accuracy is therefore a property of the weak-binding regime, and the systematic failure of the frozen-$W$ derivative kernel within the explored parameter space traces to its overscreening of the exchange channel. The accuracy of the practical kernel is an accidental cancellation of two independent errors, an underestimated quasiparticle gap and an oversized exchange term, not a hidden consistency. These results provide a controlled taxonomy of approximation failure in $GW$+BSE and a precise diagnostic for when standard workflows can be trusted.
Read the full abstract ▾
Astrophysics of Galaxies
LYRA: The formation and growth of nuclear star clusters in dwarf galaxies
Joaquin Sureda, Azadeh Fattahi, Sownak Bose et al. (+5 more)
Nuclear star clusters (NSCs) are dense massive
star clusters ubiquitous in
galactic centres across various mass regimes, present in up to $\sim30$ per cent of
dwarf galaxies with $M_\star<10^{7}\, \mathrm{M}_\odot$. Although their main growth pathways are well studied, there is still ongoing debate regarding their formation. We use the LYRA cosmological hydrodynamical simulations to study the formation and growth of NSCs in a sample of six
dwarf galaxies, where we identify NSCs with masses $M_\mathrm{NSC} \sim 10^4 - 10^6 \, \mathrm{M}_\odot$ in all
galaxies in our sample. The NSCs in our sample emerge at early times as a compact component, with the host
galaxy growing around them. This is consistent with a scenario in which NSCs are among the earliest structures to form in a
galaxy. We characterise the origin of the
stars that constitute the NSCs and explore the properties of the
stellar populations in each of these channels. We find that most of the NSC mass originates from in-situ
star formation within the NSCs themselves. While this might appear at odds with current observations, the bulk of this
star formation occurs at early times, resulting in a significant population of old and metal-poor
stars, in agreement with an early NSC formation. We also identify
galaxy-
galaxy mergers as a significant contributor to the NSC mass, with usually one merger dominating this contribution. Our results highlight the complexity in the growth history of NSCs in
dwarf galaxies and highlight the importance of considering additional growth channels for NSCs in
dwarfs galaxies.
Read the full abstract ▾
All authors Joaquin Sureda, Azadeh Fattahi, Sownak Bose, Mariya Lyubenova, Jessica E. Doppel, Thales Gutcke, Katja Fahrion, Rüdiger Pakmor
Disordered Systems and Neural Networks · Cross-listed from cs.LG
Breakdown of Local Denoising as Semantic Speciation
Guangkuo Liu, Mert Okyay, Yifan F. Zhang et al. (+3 more)
The dynamics of generative models exhibit two apparently distinct temporal windows: a speciation window, in which a sample commits to a semantic class, and a nonlocality window, in which local context windows become insufficient for generation. Motivated by evidence of their near-concurrence in a variety of frontier models, we investigate their relationship through the spatial distribution of semantic information. Under a "common cause" hypothesis, we prove that the nonlocality window must lie in the speciation window. This hypothesis postulates that semantic labels explain a fraction of the correlations between distant
tokens, a condition that is natural for many real
datasets. We further give conditions under which both windows shrink to a single limiting time as system size grows, defining a "phase transition", and verify this behavior analytically in Gaussian mixtures. Together, these results identify conditions under which semantic information explains the concurrence of speciation and nonlocality, connecting two complementary perspectives on the emergence of semantic structure in generative modeling.
Read the full abstract ▾
All authors Guangkuo Liu, Mert Okyay, Yifan F. Zhang, Fangjun Hu, Rahul Nandkishore, Xun Gao
Superconductivity
Imaging phase winding in topological superconductors with a fork-tip Josephson STM
Vladislav Poliakov and Archisman Panigrahi
The complex phase winding in a topological
superconductor remains challenging to access by conventional real-space probes. We propose a scheme to probe this winding with a fork-tip Josephson STM near an
impurity, where two superconducting tips form an interferometer sensitive to phase differences between two positions. The signal remains accessible even if the relative phase between the fork-tip and sample fluctuates, establishing a route towards a local phase-sensitive STM probe of topological superconductivity. We numerically compute the interference pattern to demonstrate that the magnitude and phase of the order parameter can be reconstructed as a function of angle, providing a route towards resolving the longstanding open experimental problem of directly detecting phase winding in topological
superconductors.
Read the full abstract ▾
Statistical Mechanics
Classification of topological phases of matter in stochastic systems
Dexin Li and Evelyn Tang
Topological phases of matter support edge states protected from random perturbations, and the identification of the discrete non-spatial
symmetries and dimensions that support such phases was systematically developed for
quantum systems and analogous platforms. While topological phases were also discovered in
stochastic systems and posited as mechanisms for key biochemical processes, a classification consistent with their Markovian constraints remains lacking, impeding generalization to new scenarios. To address this, we develop new methods including a new homotopy approach, real-space invariants and a redefinition of the point gap to classify both transient and steady states. We find robust transient states in two
symmetry classes, no
symmetry and pseudo-Hermiticity respectively, while topological steady states are expected only in systems without
symmetry. We identify the dimensions with non-trivial phases and their group structure, creating a rigorous framework for predicting robust behavior in active and living matter.
Read the full abstract ▾
Quantum Physics
When Classical Correlations Certify Entanglement Recovery
Takeru Utsumi, Yota Tachibana, Yoshifumi Nakata et al. (+4 more)
Entanglement and state distinguishability have long been central topics in
quantum foundations. While each has developed into a rich subject in its own right, they can be connected through measurements in complementary bases. This connection provides insights into
quantum and classical correlations and underlies many information-processing tasks, most notably
quantum error correction (QEC). However, it has remained largely open whether the connection between
entanglement and distinguishability extends to general measurements without assuming complementarity. We answer this question in the affirmative: the key is irreducibility induced by measurements, a much more relaxed condition than complementarity. Specifically, for POVMs satisfying an irreducibility condition, we establish a quantitative relation between the infidelity of one-sided local transformation into a maximally entangled state and the failure probability in state discrimination. We then characterize when both errors can vanish simultaneously. Our results have direct applications to
entanglement distillation and QEC. Their errors can be certified by estimating classical input-output correlations from experimentally accessible local measurements, without requiring complementarity. The results also extend to
quantum measurement theory. We derive novel trade-off relations that bridge two historically distinct approaches: information gain–irreversibility and observable noise–disturbance. Our connection between
entanglement and distinguishability via irreducibility thus offers a common framework for
entanglement distillation, QEC, and measurement trade-offs.
Read the full abstract ▾
All authors Takeru Utsumi, Yota Tachibana, Yoshifumi Nakata, Takaya Matsuura, Ryuji Takagi, Francesco Buscemi, Masato Koashi
High Energy Physics (Theory)
Exact bispectra in strongly mixed multifield inflation
Lucas Pinol
Using the effective field theory of inflationary fluctuations extended by a massive isocurvature scalar, at unit sound speed, we compute the
primordial bispectra generated by every cubic interaction of dimension four or less in the
unitary gauge, with the
curvature–isocurvature quadratic mixing resummed to all orders in the dimensionless mixing strength $\lambda=\rho/H$. Placing the mixing in the free
Hamiltonian [...], every scale-invariant tree-level bispectrum reduces to a single Schwinger-parameter integral over independent leg kernels, and what perturbation theory calls single, double and triple exchange are contact diagrams of the resummed theory. At strong mixing we unveil genuinely new, exact multifield bispectrum shapes with no correlation to the standard shapes used in data analyses. The squeezed limit carries a cosmological
collider signal with a universal frequency set by the dressed mass parameter $\mu_{\rm eff}$ at every exchange order. At weak mixing the clock coefficients are obtained in closed form and reduce [...] to the known perturbative single- and double-exchange results, exactly; the triple-exchange leading coefficient is obtained in closed form at every mass, in terms of hypergeometric functions, for the first time. At strong mixing the
collider amplitude scales as $e^{\pi(\lambda-2\mu_{\rm eff})/2}$ over the whole $(\lambda,\mu_{\rm eff})$ plane. This encompasses all previously studied regimes as particular cases [...]. A first confrontation of the six exact shapes with the Planck PR4 binned bispectrum shows a preference for strong mixing, where the cosmological
collider oscillations invade mildly squeezed configurations [...]. The shapes of all interactions over the whole plane [...] are released with the code that produced them, so that a template at any mixing and mass can be read off in milliseconds.
Read the full abstract ▾
Quantum Physics
Optimal Tolerant Testing of Lindbladian Dissipation
Jinge Bao, Yiyi Cai and Zhong-Xia Shang
Quantifying dissipation is essential for controlling
quantum noise and characterizing open-system dynamics. In practical experimental settings, residual noise may still persist despite efforts to suppress it, making it important to determine whether the dissipative strength remains within a prescribed tolerance threshold. We study this question for an unknown, time-independent Lindblad generator with bounded strength, where the jump operators are local but with unrestricted overlap, using only memoryless forward-
evolution access. The task is to distinguish dissipative strength of at most $\varepsilon_1$ from strength of at least $\varepsilon_2$, for $0 \leq \varepsilon_1 < \varepsilon_2$, measured in the canonical dissipator's normalized Frobenius norm. We give an
algorithm that solves this task in total
evolution time $O(\varepsilon_2/(\varepsilon_2-\varepsilon_1)^2)$ for all nontrivial thresholds, with constant success probability, and provide a matching lower bound $\Omega(\varepsilon_2/(\varepsilon_2-\varepsilon_1)^2)$ that establishes optimality even for adaptive protocols. This extends dissipation testing to the tolerant setting and eliminates the bounded-degree requirement, making the framework applicable to a broader range of experimentally relevant settings.
Read the full abstract ▾
High Energy Physics (Theory)
CMB Injection Bounds on Moduli Fields
Naman Agarwal, Andrew R. Frey, Ratul Mahanta et al. (+3 more)
Light scalar fields with gravitational strength interactions (
moduli) are ubiquitous in string, supergravity, and extra-dimensional models. If produced in the early universe with lifetimes exceeding the epoch of recombination, slowly decaying
moduli inject energetic particles into the Standard Model
plasma, leaving distinct imprints on the
cosmic microwave background (CMB). In this paper we systematically derive CMB injection bounds on light
moduli ($10^3\ {\rm eV}\leq m_{\rm{mod}}\leq 10^8\ {\rm eV}$) across the primary cosmological production channels:
vacuum misalignment, heavy scalar/inflaton decay, thermal emission from the
primordial plasma including production from a Hagedorn phase of hot strings. We show that these injection bounds impose stringent constraints that are complementary to both the standard cosmological
moduli problem and fifth force bounds.
Read the full abstract ▾
All authors Naman Agarwal, Andrew R. Frey, Ratul Mahanta, Anshuman Maharana, Fernando Quevedo, Gonzalo Villa
Strongly Correlated Electrons
Neural-quantum-state based downfolding of the three-band Emery model for cuprates and nickelates
Hannah Lange, Julius F. A. Tirpitz and Annabelle Bohrdt
Understanding the physics underlying high-temperature superconductivity in cuprates and, more recently, infinite-layer nickelates has remained a central challenge in condensed-matter physics. We establish neural
quantum states (NQS), specifically Hidden
Fermion Determinant States (HFDS), as a scalable variational approach to the three-band Emery model of the copper- and nickel-
oxide layers in these materials. After benchmarking HFDS against
matrix product states on width-two geometries, we study ground states of fully two-dimensional (2D) systems of up to $10\times10$ unit
cells ($300$ sites). We characterize the momentum-space distribution of dopants and find a pronounced electron-hole dichotomy similar to cuprate experiments. We further downfold the three-band model to effective single-band descriptions by constructing interacting Wannier functions. We consider a wide range of parameters – from the charge-transfer regime relevant to cuprates to the Hubbard-Mott regime of nickelates, as well as systematic scans of the charge-transfer gap that has been demonstrated to impact the critical superconducting temperatures. Across all regimes, the effective model significantly deviates from the usual
Fermi-Hubbard model: The typical ratio $U/t$ is enhanced, some parameters experience a significant doping dependence, and sizable terms beyond the conventional Hubbard model are present, most notably a density-assisted hopping $t_n$. Notably, in all effective models, $t_n$ has the largest contribution to particle-hole asymmetry, rather than next-nearest-neighbor hopping contributions. The effective parameters sensitively depend on the charge-transfer energy, doping, and interaction ratios. Our results establish HFDS as an efficient tool for studying the 2D Emery model and demonstrate that single-band descriptions can require interaction terms generated by the underlying multi-band models.
Read the full abstract ▾
Superconductivity
Anisotropic interface-confined superconductivity in FeTe-based heterostructures
Bicky Singh Moirangthem, Kamal R. Joshi, Zi-Jie Yan et al. (+4 more)
Interface-confined superconductivity emerges from the interaction of electronic states across chemically distinct boundaries, providing a route to engineer superconducting phases where magnetism and
topology coexist. Determining the intrinsic nature of such superconductivity, however, is challenging because the superconducting layer is only a few nanometers thick and buried beneath several normal layers. Here, we measure the whole-sample Meissner response of six $\mathrm{FeTe}$-based
heterostructures in a uniform
magnetic field using a frequency-domain tunnel-diode resonator. In the ultrathin limit, the conventional normalization of the measured susceptibility, $\chi(T\to0)=-1$, fails by tens of percent. We establish the appropriate calibration and invert $\chi(T)$ to determine the London penetration depth $\lambda(T)$. Two key results emerge. First, the broad transitions observed in $\chi(T)$ arise naturally from the extreme geometry and large $\lambda$, without requiring chemical or structural inhomogeneity; the extracted $\lambda(T)$ closely tracks the resistive transition. Second, $\lambda(T)$ and the corresponding superfluid density are inconsistent with a fully gapped isotropic $s$-wave state and instead indicate a strongly anisotropic order parameter possibly with line nodes or deep gap minima. The inferred $\lambda(0)$ is of order $1\,\mu$m, consistent with an independent analysis of the 2D phase stiffness. Despite the distinct chemical,
magnetic, and topological character of the three overlayers, all six FeTe
heterostructures exhibit similar low-temperature power-law behavior, with no systematic dependence of the superconducting response on overlayer identity. These results point to the interfacial $\mathrm{FeTe}$ layer as the common origin of superconductivity.
Read the full abstract ▾
All authors Bicky Singh Moirangthem, Kamal R. Joshi, Zi-Jie Yan, Pu Xiao, Lok-Kan Lai, Cui-Zu Chang, Ruslan Prozorov