High Energy Physics (Phenomenology)
Top-quark mass interpretation from simulation of top-flavoured mesons
Gennaro Corcella and Alexander Lind
The interpretation of the top
quark mass measurements in terms of well-known field theory definitions has been the topic of a long-standing discussion. In this paper we reconsider this issue and simulate fictitious top-flavoured
mesons, whose mass can be related to any top mass definition, such as the pole mass, by means of Heavy
Quark Effective Theory. We explore final-state observables for top-pair production in $e^+e^-$ and
hadron collisions, and relate the top mass in standard $t\bar t$ events to the pole mass extracted from top-
meson samples simulated with Pythia 8.3. Our results are in agreement with the expectation of an uncertainty about $200$-$300$ MeV, hence of the order of $\Lambda_{\rm QCD}$.
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Astrophysics of Galaxies
Using Scattered Near-Infrared Light to Map Water Ice in Prestellar Cores with SPHEREx
Tamojeet Roychowdhury, Jennifer B. Bergner, Jens Kauffmann et al. (+2 more)
We present the first coreshine-derived, spatially-resolved maps of the 3 $\mu$m H$_2$O ice absorption feature in four prestellar cores, using SPHEREx spectra. Ices are a key component of dense cores in molecular clouds, playing a central role in the chemistry of
planet formation around young
stars. However, spatially resolved abundance studies remain limited, typically relying on unevenly distributed background
star sightlines. Here, we take advantage of the all-sky spectrophotometric capabilities of SPHEREx to construct ice absorption maps with uniform spatial resolution using the illumination of dense cores by scattered
Galactic radiation, or coreshine. To demonstrate proof of concept, we analyse the spatially varying H$_2$O ice absorption in four nearby (~140 pc) prestellar cores - L1544, CrA 151, L260 and L1512. Two cores follow the expected spatial trend of ice absorption peaking at the centre, but the two densest cores show a surprising drop in observed ice absorption in the innermost regions. To interpret the absorption maps, we construct analytical and simulated models of a Bonnor-Ebert sphere illuminated by scattering. We study the effects of different
geometric configurations, ice mass fractions, and spatial differences in ice composition. None of these can explain the reduced central absorption, pointing to an unexplained physical or chemical effect operating in the densest prestellar regions. Our simulations further show that spectra derived from coreshine provide a robust tracer of spatially varying ice density and composition, establishing SPHEREx scattered-light spectroscopy as a powerful new probe of ice in dense cores.
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All authors Tamojeet Roychowdhury, Jennifer B. Bergner, Jens Kauffmann, Thushara G.S. Pillai, Silvia Spezzano
High Energy Physics (Phenomenology)
Coherence from interference: a solvable model of sub-GeV dark matter-nucleus scattering
Lynn Lin, Tongyan Lin and Momei Fang
How do dark matter-
nucleus interactions transition from the regimes of coherent scattering, where single
phonons are produced, to that of individual
nuclear recoils? Answering this question relies on understanding multiphonon excitations. Multiphonons are important for interpreting low-threshold direct detection experiments, yet are computationally prohibitive to compute. In this paper, we employ a 1D $N$-site
crystal lattice model where dark matter scattering can be computed exactly. We show that the only difference between coherent and incoherent scattering is that conservation of
crystal momentum is enforced in coherent scattering. The momentum conservation constraint becomes less important as more
phonons are produced, yielding the transition to incoherent scattering. Using numerical calculations of the 1D structure factor, we also obtain quantitative validation of using an incoherent approximation to compute sub-GeV dark matter scattering in realistic 3D
crystals.
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High Energy Physics (Phenomenology)
Multi-component Dark Matter in a Novel Three-Loop Inverse Scotogenic Seesaw Model
Asmaa Abada, Nicolás Bernal, A. E. Cárcamo Hernández et al. (+4 more)
We consider a model which provides an explanation of the origin of light
neutrino masses, the
baryon asymmetry of the Universe – via leptogenesis – and explains the observed dark matter relic abundance with several components. In this scenario, Majorana masses of the active
neutrinos are produced by the inverse seesaw (ISS) mechanism with the
lepton-number-violating mass parameter being dynamically generated at three loops with a novel
topology. This model is based on an extension of the Standard Model gauge
symmetry by a global $U(1)'$ and a discrete $\mathbb{Z}_2\otimes \mathbb{Z}_3$. The latter, which is responsible for the radiative origin of the ISS
lepton-number-violating parameter, survives the spontaneous breaking of the global $U(1)'$ and, at the same time, ensures the stabilization of the dark sector. The lightest particles carrying non-trivial residual charges are stable, becoming potentially viable dark matter candidates. The model complies with bounds and constraints from
neutrino data,
collider and high-intensity charged
lepton flavor-violating observables, as well as dark matter relic density and direct detection. To efficiently explore the model's high-dimensional parameter space and identify phenomenologically viable regions, we perform a global numerical scan using the MultiNest
algorithm.
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All authors Asmaa Abada, Nicolás Bernal, A. E. Cárcamo Hernández, Vishnudath K. N., Sergey Kovalenko, Téssio B. de Melo, Salvador Urrea
Astrophysics of Galaxies
S301 and friends: Measuring the spin of Sgr A*
T. Piran, P. Amaro-Seoane, B. Aytac et al. (+13 more)
The discovery of S301 (
GRAVITY Collaboration et al., 2026) with pericenter distance rp= 280rg and eccentricity e=0.9825, opens the prospect of measuring the
spin parameter of Sgr A* through Lense–Thirring (LT) nodal precession. A major obstacle is Newtonian confusion: any non-spherical extended mass distribution can also induce nodal precession. We aim to separate the LT
spin signal of S301 from the Newtonian nodal precession. We compare the secular Newtonian torque exerted by a disk or flattened mass distribution on the orbits of S301 and of the apocenter-matched reference
stars S2, S55, and S38, using analytic estimates validated by numerical orbit-averaged torque calculations. For a disk or flattened distribution extending beyond the
stellar pericenters, the secular Newtonian torque on a highly eccentric orbit is controlled mainly by the apocenter, whereas the LT signal is controlled mainly by the pericenter. Thus
stars with apocenters comparable to S301's but much larger pericenters, in particular S2, but also S55, and S38, experience comparable Newtonian torques while having ~ 30 times smaller LT signals (for S2). Their measured precessions, or upper limits on them, can therefore calibrate the mass and orientation of the Newtonian background for subtraction from S301's precession. The Schwarzschild apsidal advance of S301 further rotates the orbit's pericenter relative to any disk, producing a systematic time dependence in the Newtonian contribution, while the LT signal remains fixed by the
spin vector. Granularity of the perturber population sets a
stochastic floor on this subtraction, which orbit- and
star-averaging suppress. With continued
GRAVITY+ astrometry and Extremely Large
Telescope (ELT) spectroscopy, the in-plane
spin projection may be within near-term reach; the full
spin vector requires a much longer-term accumulation of the LT apsidal signal.
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All authors T. Piran, P. Amaro-Seoane, B. Aytac, G. Bourdarot, A. Burkert, D. Calderon, J. Cuadra, F. Eisenhauer, R. Genzel, S. Gillessen, S. Joharle, F. Mang, T. Ott, D.C. Ribeiro, M. Sadun Bordoni, R. Sari
High Energy Physics (Phenomenology)
Gravitational waves decay in vacuum
Diego Blas and José Antonio Oller
We show that gravitational waves (GW), treated as coherent graviton states, decay into
photon pairs in
vacuum. The process, even if suppressed by $G^2$, is lifted by two effects combined: the expected factor of the graviton number squared, $N^2$, and the coherence of the wave. We perform the calculation describing both
gravity and the
photons as quantized fields, though we show that the effect admits a semiclassical description once the metric is solved to second order. We estimate the resulting rates for compact binaries and a
stochastic background, including the effect from stimulated decay to the
cosmic microwave background (CMB). In theories with light degrees of freedom, an analogous decay into them is also possible, and more relevant for ultralight dark matter, as it can entail huge occupation numbers. We derive first constraints on cosmological GW sources by the corresponding injection of
photons from CMB spectral distortions, extragalactic backgrounds, and light-
nuclei photofission. In summary, the decay of GWs into
photons offers a new (challenging) handle on the detection of GW sources, and represents a new mechanism to generate other particles across
cosmic history.
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Astrophysics of Galaxies
Observational Evidence for Anisotropic Metal Excess around Galaxies
Cheqiu Lyu, Enci Wang, Zeyu Chen et al. (+4 more)
The exchange of matter and energy between
galaxies and their surroundings drives the
cosmic baryon cycle, yet mapping metal transport remains an observational challenge. While simulations predict that
galactic winds escape anisotropically along minor axes, evidence for chemical enrichment in neighboring
galaxies is limited. We analyze 1,433
galaxy pairs from the Dark Energy Spectroscopic Instrument survey and detect a gas-phase
metallicity excess of 14.6% $\pm$ 3.7% to 24.2% $\pm$ 2.6% in neighbors aligned with the minor axis of massive primary at projected separations of 15–60 kpc, qualitatively consistent with IllustrisTNG simulation. Permutation tests indicate that this excess varies from a marginal detection ($>$92% confidence) at closer separations (15–30 kpc) to a significant signal ($>$98% confidence) at intermediate separations (30–60 kpc). Here, we show that these results provide empirical constraints on
galactic feedback models and are consistent with a scenario where anisotropic
outflows can enrich nearby
galaxies, a mechanism that complements other environmental processes.
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All authors Cheqiu Lyu, Enci Wang, Zeyu Chen, Chengyu Ma, Yangyao Chen, Haoran Yu, Xu Kong
High Energy Physics (Phenomenology)
Bound-state beta decay of tritium: Path to first observation and novel approach to direct neutrino mass measurement
Evgeny Akhmedov, Thierry Lasserre, Ferenc Glück et al. (+1 more)
Bound-state $\beta$-decay of tritium, the process, in which the final-state electron is created in a bound atomic state of the produced ${\rm ^3He}$ atom instead of freely flying away, is predicted by the standard theory of weak interactions but has not been observed so far. We study the possibility of its experimental observation through the detection of
photons from radiative decay of the excited atomic states of neutral ${\rm ^3He}$ populated by this process. We also propose a novel approach to direct
neutrino mass measurement and sterile
neutrino search based on accurate determination of the speed of the produced ${\rm ^3He}$ atoms through Doppler broadening of the emitted
photon lines.
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All authors Evgeny Akhmedov, Thierry Lasserre, Ferenc Glück, Alejandro Saenz
Soft Condensed Matter
Controlling Turbulent Flows in Compressible Active Liquid Crystals
Dimitrios Krommydas, Paarth Gulati, Aparna Baskaran et al. (+1 more)
Motivated by experiments on light-patterned, quasi-2D active suspensions that exhibit large density variations, we develop a continuum theory of compressible active nematics–suspensions of apolar rods whose orientation is invariant under $\pi$ rotations. Under spatially patterned activity, the extensile isotropic active pressure expels material from high-activity regions and accumulates it in low-activity ones; an exactly solvable scalar reduction shows that the resulting density contrast is governed by a single dimensionless parameter, linear in the compressibility. Using compressibility as a tuning knob, we then steer active
turbulence from high- to low-activity regions and, at sharp activity interfaces, stabilize an analytically tractable dynamical steady state: a one-dimensional chain of
vortices held by soft, activity-induced confinement. Our results establish compressibility as a control parameter for density variations and turbulent flow in active nematic suspensions.
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All authors Dimitrios Krommydas, Paarth Gulati, Aparna Baskaran, M. Cristina Marchetti
Solar and Stellar Astrophysics
Syntriod: A Robust Initial Parameter Estimator for Radial Velocity Curve Solutions Beyond Conventional Sampling Limits
Emre Barbaros, Hasan Ak and N. Filiz Ak
We present Syntriod, an orbital-phase domain radial velocity (RV) template-based
algorithm designed to provide robust initial orbital parameter estimates for spectroscopic binaries across diverse observational sampling conditions. Rather than performing full orbital inference, Syntriod constrains the parameter space with physically consistent solutions to guide subsequent optimization procedures. We evaluate its performance using 10,000 synthetic Keplerian orbits spanning diverse configurations and sampling regimes. For well-sampled
datasets ($N_{obs} \ge 8$), Syntriod recovers orbital periods with relative accuracies of order $10^{-3}$. At the theoretical sampling limit ($N_{obs} = 6$), the method maintains a ~94% success rate, while classical period-search techniques like Lomb-Scargle become increasingly affected by aliasing. Even below this limit ($N_{obs} = 5$), Syntriod recovers the correct orbital solution in ~83% of cases, showing gradual degradation rather than catastrophic failure. We further evaluate the method on 12 real spectroscopic binary systems (HD 160934, Phi Cyg, Capella A, Kepler 16, KIC 3858884, KIC 6867766, KIC 2445134, KIC 3003991, DU Boo, HL Dra, FP Boo, and AK Her) spanning broad orbital periods and eccentricities. Syntriod consistently reproduces literature solutions even when
datasets are randomly subsampled to sparse regimes. Where a full Keplerian solution becomes underconstrained ($N_{obs} \le 4$), the
algorithm transitions to linear dynamical relations, recovering parameters such as mass ratio ($q$) and systemic velocity ($\gamma$) with success rates exceeding 99%. These results demonstrate that Syntriod provides reliable, computationally efficient initial parameter estimates across well-sampled and sparse regimes, making it a practical pre-solver for modern orbit-fitting pipelines and large spectroscopic surveys.
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Statistical Mechanics
Effective Field Theory of Operator Scrambling from Strong-to-Weak Symmetry Breaking
Bai-Lin Cheng, Shao-Kai Jian and Zhi-Cheng Yang
Operator scrambling is commonly diagnosed by the growth of out-of-time-ordered correlators (OTOCs), yet a general
symmetry principle underlying their effective dynamics has remained elusive. For Brownian or short-time-correlated large-$N$ Majorana systems, we develop a
symmetry-based effective field theory for operator scrambling, organized by a strong-to-weak U(1)
symmetry breaking in operator space. The key observation is that, in the noninteracting
fermion limit, the four-fold Keldysh contour representation of an OTOC admits an emergent strong U(1)
symmetry in a doubled
Hilbert-space description, even when the original system has no ordinary conserved quantity. The associated slow mode is the phase of the strong-charge creation operator, whose conjugate density is identified with the local operator size. Generic interactions explicitly break the strong
symmetry and generate a mass term at lowest order for the would-be Goldstone mode, thereby converting diffusive operator spreading into chaotic growth. We further show that higher-order
symmetry breaking terms are tightly constrained by an emergent duality that combines time reversal with contour permutation. This duality fixes the effective action up to quadratic order in the response field, relates the multiplicative noise strength directly to the Lyapunov exponent, and makes the positivity of the Lyapunov exponent a consequence of convergence of the real-time path integral. The resulting OTOC dynamics is governed by a noisy FKPP equation, which captures within a unified framework the early-time exponential growth, ballistic propagation, nonlinear saturation, and
stochastic front broadening of operator scrambling. We verify this construction in a Brownian SYK chain, where a direct saddle-point expansion reproduces the
symmetry-based effective action. Our results reveal a
symmetry origin of operator-size hydrodynamics and scrambling.
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Quantum Physics
Efficient computation of real-time correlators using Pauli Propagation
Alexander F. Kemper, Raghav G. Jha, Arnab Bachhar et al. (+3 more)
Pauli propagation has shown promise for classically simulating
quantum dynamics by evolving observables directly in the Heisenberg picture. In this work, we investigate its use for computing real-time two-point time-ordered correlators in one- and two-dimensional
quantum systems. One major limitation of Pauli propagation is the rapid growth in the number of Pauli strings beyond short times. We overcome this limitation by combining accurate short-time Pauli-propagation data with time extension methods based on a positivity condition and the observation that the dynamics are often dominated by a small number of characteristic frequencies. This combined approach extends correlation functions far beyond the directly accessible time window while avoiding the exponential proliferation of Pauli operators. We demonstrate that the resulting correlators retain the relevant dynamical and spectral information. Our results broaden the regime in which classical methods can reliably probe the real-time dynamics of interacting
quantum many-body systems.
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All authors Alexander F. Kemper, Raghav G. Jha, Arnab Bachhar, Goksu C. Toga, Mariano Guerrero Perez, Nicholas J. Mayhall
High Energy Physics (Theory)
Feynman Tree Theorem and the Gelfand–Yaglom Formula
Ipak Fadakar, Guilherme L. Pimentel and Behrang Tafreshi
The Gelfand–Yaglom formula equates the one-loop determinant of a Schrödinger operator with Dirichlet boundary conditions to the solution of an initial value problem. Following a suggestion by Polyakov, we provide a new diagrammatic proof of this formula as a direct application of the Feynman Tree
Theorem. By cutting the one-loop determinant, we re-express it as a sum of tree diagrams. These trees explicitly encode the solution to the Gelfand–Yaglom initial value problem. We extend this diagrammatic framework to general boundary conditions and comment on a potential generalization to
quantum field theory.
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High Energy Physics (Theory)
Claudia de Rham, Andrew J. Tolley, Zhuo-Hui Wang et al. (+1 more)
Dual-resonance models realize crossing
symmetry, Regge behavior and infinitely many resonances in a compact analytic form but their canonical tree-level realizations fall short of genuine S-
matrix unitarity. Here we explicitly construct fully
unitary dual-resonance amplitudes distinct from the conventional worldsheet construction. The zero-width resonance towers are promoted into a physical absorptive spectrum that retains their characteristic crossing and Regge organization, while unitarizing the amplitude through a mechanism distinct from standard eikonalization. The resulting S-
matrices are also local and analytic, and can contain controllable second-sheet Regge trajectories as well as substantial inelasticity. More broadly, our construction opens up a new route to charting the space of consistent strongly coupled S-
matrices.
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All authors Claudia de Rham, Andrew J. Tolley, Zhuo-Hui Wang, Shuang-Yong Zhou
High Energy Physics (Phenomenology)
Simplex Demixing: Disentangling Multiple Light-Flavor Jets at Colliders
Gregorio de la Fuente and Jesse Thaler
Providing a practical and
hadron-level definition of multiple jet
flavors has been a long-standing challenge in
collider physics. Previous work has introduced a data-driven, operational definition of
quark and
gluon jets, but no robust generalization beyond two jet categories presently exists. To address this, we introduce a machine-learning framework called "simplex demixing” to extract $T$ jet
flavors (or topics in the statistics literature) from $M$ data samples (or mixtures) with minimal constraints. Intuitively, our procedure identifies the maximally separable categories in the data, translating a multi-category classifier on the $M$ mixtures into a bounded
geometric object with $T$ vertices. We first demonstrate our procedure on a toy problem to infer the truth-level fractions of down-
quark, up-
quark, and
gluon jets from synthetic mixtures of the three pure samples. We then propose a tag-and-probe strategy to extract multiple light-
flavor categories in a more realistic
collider setting involving dijet production. As expected, the identifiability of jet
flavors depends on their relative abundance in the samples and the
hadron-level information available to the classifier architecture. Our work opens the door to data-driven extractions of multiple jet
flavor properties at the Large
Hadron Collider.
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High Energy Physics (Theory)
Split Heun functions via blown-up surface defects
Saebyeok Jeong and Tommaso Pedroni
We study resonant solutions of the Heun equation and its confluent limits that arise in the Nekrasov-Shatashvili (NS) limit of four-dimensional $\mathcal{N}=2$ $\mathrm{SU}(2)$ gauge theories with fundamental hypermultiplets. At the resonant loci $2a/\hbar\in\mathbb{Z}$ in the Coulomb branch parameter $a$, the Floquet multipliers coalesce and the instanton expansions of the bulk and surface defect NS functions develop poles of increasing order. We derive blow-up equations involving exclusively NS functions and use them to resum these singular expansions. The resulting resummed bulk and surface defect NS functions reveal the analytic structure of the gauge-theoretic solutions near the resonant loci, including the branch structure of the accessory parameter and of the Floquet solutions that is obscured by the term-by-term instanton expansion. At resonance, the resummed accessory parameters and suitably normalized defect wavefunctions admit finite limits that describe periodic or antiperiodic solutions at the edges of spectral gaps and allow us to construct their logarithmic companions. We then identify distinct nested mass loci governing gap closure and semisimple resonant monodromy. On the larger locus the band-edge accessory parameters coalesce, while on the smaller locus two independent resonant (anti)periodic Floquet solutions survive. We develop the general resummation procedure for $N_f=(n_0,n_1)$ theories with $n_i\leq 2$ $(i=0,1)$, and demonstrate it explicitly for the $N_f=(1,1)$ theory.
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High Energy Physics (Theory)
Analytic thermal bootstrap in momentum space: From thermal OPE to QNMs
Julien Barrat, Deniz N. Bozkurt, Enrico Marchetto et al. (+2 more)
We initiate a bootstrap program that relates ultraviolet data, encoded in the thermal OPE, to infrared observables, namely, the low-frequency behavior and quasinormal modes. Starting from KMS-symmetric completions of individual thermal OPE blocks, which play the role of thermal Polyakov blocks, we construct their
Fourier transform, yielding an asymptotic expansion of retarded thermal correlators valid at any spatial momentum. We use these results to derive inversion formulae and connect thermal OPE data to the analytic structure of retarded correlators in the complex frequency plane. Under the assumption of meromorphicity, the inversion formulae express OPE coefficients in terms of the quasinormal-mode frequencies, leading to nontrivial sum rules, constraints on the quasinormal spectrum, and its asymptotics at large spatial momentum. We illustrate these results in free theories, two-dimensional CFTs, the large-$N$ limit and $\varepsilon$-expansion of the $\mathrm{O}(N)$ model, and the $R$-current correlator of strongly coupled $\mathcal N = 4$ SYM at zero spatial momentum. As a byproduct, we derive universal asymptotic formulae for thermal OPE coefficients of heavy operators, resolving their dependence on
spin and extending previous results at zero spatial separation. We test these formulae in the three-dimensional Ising CFT, finding good agreement between the resulting truncated correlators and Monte Carlo data.
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All authors Julien Barrat, Deniz N. Bozkurt, Enrico Marchetto, Alessio Miscioscia, Elli Pomoni
High Energy Physics (Phenomenology)
Probing long-range $L_e-L_\mu$ forces with supernova neutronization burst neutrinos
Amol Dighe, Sadashiv Sahoo and Manibrata Sen
Ultralight gauge
bosons associated with flavour-dependent leptonic
symmetries generate long-range potentials that can modify
neutrino flavour
evolution over astrophysical distances. We investigate the sensitivity of neutronization-burst
neutrinos from core-collapse
supernovae for such interactions in the anomaly-free $U(1)'_{L_e-L_\mu}$ framework. Incorporating the long-range potential into
supernova neutrino oscillations, we simulate the corresponding signal in the Deep Underground
Neutrino Experiment (DUNE) using a realistic detector response of its 40 kt
Liquid Argon Time Projection Chamber. We show that in the range where the long-range potential dominates over or is comparable to the
vacuum oscillation term, the electron-
neutrino survival probability can be significantly modified. This would produce observable distortions in the time and energy distributions of the neutronization burst
neutrino spectra. Our results demonstrate that future observations of
galactic supernova neutrinos, particularly from a nearby event such as Betelgeuse, can provide a sensitive and complementary probe of flavour-dependent long-range leptonic interactions.
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Cosmology and Nongalactic Astrophysics
Interlopers as Signal in Line Intensity Mapping
Anirban Roy
Line intensity mapping measures the combined emission of atomic and molecular lines from unresolved
galaxies, offering a way to map
cosmic structure across enormous volumes. A single observed frequency, however, contains emission from several spectral lines at different
redshifts. These interlopers are usually removed before cosmological inference. We show that this removal is not always optimal. Once the possible emitting lines and their
redshifts are included in the model, interlopers become additional tracers of large-scale structure at other epochs, projected into the coordinate system of the target line. We formulate interloper treatment as a Fisher decision problem, requiring both improved precision and parameter bias below a chosen tolerance. In SPHEREx forecasts for H$\alpha$ with [O III], H$\beta$, and [O II] interlopers, and in FYST forecasts for [C II] with CO interlopers, $\Omega_m h^2$ and
baryon acoustic oscillation (BAO) distance measurements are comparatively robust to astrophysical calibration errors, whereas the clustering amplitude $\sigma_8$ and the dark energy parameters $w_0$ and $w_a$ are more sensitive to the adopted line model and priors. The BAO distance measurement gives a simple physical picture: modeling interlopers turns two observed bands into a transverse BAO distance ladder over $0.7\lesssim z\lesssim5.8$. Interlopers are therefore not only contaminants to remove, but a calibrated component of the cosmological signal model for future LIM surveys.
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High Energy Physics (Theory)
Carrollian bosonic supergravity at order $\alpha'$ and the universal cancellation of higher-curvature divergences
Eric Lescano
We prove that the Carrollian limit of bosonic supergravity remains finite after including the complete set of four-derivative terms arising from the first $\alpha'$-correction, for an arbitrary Carrollian geometry, i.e., without imposing compatibility conditions on the Carrollian fields. The proof rests on a small set of exact identities satisfied by the leading term of the relativistic Riemann tensor, which is entirely controlled by the intrinsic torsion $K_{\mu \nu}=\frac12 \mathcal{L}_{\tau} h_{\mu \nu}$ of the Carrollian structure. We explicitly construct the finite action in a manifestly covariant form: the gravitational sector is purely electric, depending only on $K_{\mu \nu}$ and on its derivative along $\tau^{\mu}$, while the Carrollian
curvature and the twist of $\tau_{\mu}$ drop out. We then show that higher-
curvature contributions obey a universal scaling rule: every scalar built from $N$ relativistic Riemann tensors grows at most as $w^{2N}$ in the Carrollian expansion, so that all purely gravitational $\alpha'^{N-1}$-corrections admit a finite Carrollian limit for arbitrary Carrollian geometries. As applications we show that the $\alpha'^2$- and $\alpha'^3$-corrections of bosonic string theory, including the terms proportional to $\zeta(3)$, are finite and non-vanishing in this limit, and that the compatibility conditions $\nabla_{\mu} h_{\nu \rho}=\nabla_{\mu} \tau^{\nu}=0$ trivialize the whole gravitational sector.
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High Energy Physics (Theory)
The Tachyon Chern-Simons action with a generic tachyon field, and baryons in V-QCD
Jean-Loup Raymond, Matti Järvinen, Elias Kiritsis et al. (+2 more)
Consistency with global
flavor anomalies requires the presence of Chern-Simons terms in
holographic models of QCD. Such terms are analyzed in a setup arising in the
holographic V-QCD model, where
chiral symmetry breaking is implemented through the condensation of a complex scalar field, the tachyon. Using the superconnection formalism, the Tachyon-Chern-Simons terms are constructed explicitly in the general case, where the tachyon is any complex
matrix in
flavor space. This general case covers, among other things, backgrounds where different
quark flavors have different masses. These new results are used to analyze the structure of the
baryon solutions in the presence of nonzero
quark masses. Expressions for the
baryon number current and the total
baryon number are found, and the
baryon number is shown to be equal to the topological instanton number of the
baryon solution. The effective four-dimensional pion action is analyzed and is shown to reproduce the
chiral Lagrangian, including the Skyrme and Wess-Zumino-Witten terms.
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All authors Jean-Loup Raymond, Matti Järvinen, Elias Kiritsis, Francesco Nitti, Edwan Préau
High Energy Physics (Theory)
Kaluza-Klein Perturbation Theory from Exceptional Field Theory
Camille Eloy, Olaf Hohm, Camilla Lavino et al. (+2 more)
We develop the perturbation theory of ten and eleven-dimensional supergravities on a large class of Kaluza-Klein backgrounds including familiar AdS examples such as AdS$_5\times S^5$, but also more general
manifolds such as black hole geometries. Employing ${\rm E}_{6(6)}$ exceptional field theory with the backgrounds characterized by a generalized Scherk-Schwarz ansatz, we determine the first order field equations for the fluctuations that are gauge invariant under linearized generalized diffeomorphisms. We then present the details of the
Higgs mechanism for all fields including
spin-2 for the subset of backgrounds in which higher-form gauge fields vanish. We use a recently established machinery based on homotopy transfer that allows one to separate the fields into gauge invariant physical modes and pure gauge unphysical modes to all orders in perturbation theory. Finally, as a first application for backgrounds with higher-form gauge fields switched on, we analyze part of the spectrum of ten-dimensional Kaluza-Klein modes of type IIB supergravity around a Kerr-Newman AdS$_5$ black hole that in the near horizon limit becomes a fibered product of AdS$_2$ and a squashed three-sphere.
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All authors Camille Eloy, Olaf Hohm, Camilla Lavino, Henning Samtleben, Yehudi Simon
High Energy Physics (Theory)
Neural Spectral Bias and Conformal Correlators II: Modular and Annulus Bootstrap
Kausik Ghosh, Sidhaarth Kumar, Vasilis Niarchos et al. (+1 more)
We develop a neural network bootstrap framework for reconstructing partition functions of two-dimensional conformal field theories (CFTs) based on modular invariance and the Cardy condition, which are recast as crossing equations for four-point correlators. For
torus partition functions, we use the twist-field representation in the symmetric-orbifold description to map modular S-invariance to four-point crossing and focus on the diagonal kinematics of four insertions on a line. For annulus partition functions, we formulate open/closed channel duality as crossing
symmetry for mixed four-point functions of defect-changing operators in interface CFT. In both cases, the reconstruction problem is formulated in the anchored-bootstrap form, where the crossing constraints are supplemented by minimal spectral input (a gap) and anchor data. We solve this under-determined problem by using lightweight feed-forward neural networks to parametrise the correlators and their corresponding partition functions. A key ingredient of this approach is the spectral bias of the neural networks in the lazy training regime, which selects specific crossing-symmetric configurations. This reformulation unifies standard modular and annulus constraints in two dimensions with the anchored neural approach for CFT correlators, providing a new way to reconstruct full partition functions from sparse data with remarkable accuracy.
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All authors Kausik Ghosh, Sidhaarth Kumar, Vasilis Niarchos, Andreas Stergiou
Cosmology and Nongalactic Astrophysics
Correlated signals of ultralight scalar dark matter in pulsar timing
Joshua W. Foster, Kimberly K. Boddy, Jeff A. Dror et al. (+5 more)
Pulsar timing arrays (PTAs) are sensitive to ultralight dark matter (ULDM) in the $10^{-24}$-$10^{-20}\,\mathrm{eV}$ mass range, with existing
datasets already probing otherwise open parameter space and future PTAs promising substantial improvements in reach. Thus far, however, PTA searches for ULDM have typically been formulated using limiting descriptions. Analyses are performed in either the fully correlated limit, in which the local ULDM amplitude is shared across the array, or the fully uncorrelated limit, in which each
pulsar has an independent local amplitude. Because the transition between these regimes occurs within the PTA-sensitive mass range, projected sensitivities and data-derived constraints can depend on which limiting description is assumed. For the first time, we develop a self-consistent analysis that treats the ULDM field as a Gaussian random field with finite spatial correlations, allowing the amplitude prior used in PTA signal models to interpolate continuously between the fully correlated and fully uncorrelated limits. We apply the framework to both linearly and quadratically coupled scalar ULDM, the latter including the universal gravitational signal sourced by the oscillating ULDM pressure.
Pulsar-distance uncertainties are incorporated through an augmented latent-field prior, and the resulting distance-marginalized latent-amplitude distribution is represented with a normalizing-flow surrogate. We validate the method on mock PTA
datasets, including blinded signal injection tests.
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All authors Joshua W. Foster, Kimberly K. Boddy, Jeff A. Dror, Vincent S.H. Lee, Andrea Mitridate, Tristan L. Smith, Kelsie Taylor, Tanner Trickle
Astrophysics of Galaxies
Vigorous turbulence driven by quasar-mode feedback in a cluster core
Satoshi Yamada, Shutaro Ueda, Hirofumi Noda et al. (+9 more)
Quasars are among the most luminous objects. They are powered by
accretion onto supermassive black holes. They are thought to impact cosmological
evolution primarily through energetic winds, known as
quasar-mode feedback, yet the efficiency and spatial extent of this process remain poorly constrained. Here we present X-Ray Imaging and Spectroscopy Mission (XRISM) observations of H1821+643—the nearest
galaxy cluster with a central
quasar (
redshift z = 0.297)—which was a rare opportunity to directly probe
quasar-mode feedback in the intracluster medium. High-resolution spectroscopy reveals exceptionally broadened Fe XXV emission lines from the intracluster medium, with a velocity dispersion of approximately 300 km/s, far exceeding values observed in nearby cluster cores. These lines originate predominantly at radii of 20-100 kpc from the centre. Assuming that
turbulence from a
quasar-driven shock led to the broadening of the lines, the energy injected by the
quasar beyond
galactic scales ($\gtrsim$20 kpc) is estimated to be $\gtrsim$1-10% of its radiative energy. Notably, this feedback efficiency exceeds previous multiwavelength estimates by orders of magnitude ($\lesssim$0.01%) and reaches the levels required by the latest cosmological hydrodynamical simulations. This finding of vigorous
turbulence indicates that
quasar-mode feedback plays a central role in regulating
galaxy and cluster
evolution at high
redshift.
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All authors Satoshi Yamada, Shutaro Ueda, Hirofumi Noda, Yutaka Fujita, Misaki Mizumoto, Kentaro Nagamine, Claudio Ricci, Shoji Ogawa, Taiki Kawamuro, Shinya Yamada, Yuichi Terashima, Yoshihiro Ueda
Cosmology and Nongalactic Astrophysics
Cosmological evolution with decaying dark matter: an integral-equation approach
Nanoom Lee, Anna Bencke, Marc Kamionkowski et al. (+1 more)
We present CLASSIER-DDM, an extension of the Boltzmann solver CLASSIER that implements the decaying dark matter (DDM) model via its integral-equation approach. The code handles generic two-body decays of a dark matter particle into two lighter decay products with arbitrary masses, naturally encompassing both massless (dark radiation) and massive (warm) decay products, with their perturbations evaluated via integral equations solved iteratively. We describe the numerical implementation in detail, including the background
evolution, the iterative perturbation
evolution, and a small-scale analytic approximation. A modest number of iterations is sufficient to achieve sub-$0.1\%$ convergence in the matter power spectrum and the CMB
lensing power spectrum across the observationally relevant parameter space. We find that a hundred momentum bins for the decay product perturbations are sufficient to achieve $\mathcal{O}(0.1\%)$ accuracy in the matter power spectrum today up to $k \sim 3\,{\rm Mpc}^{-1}$. The code achieves $\mathcal{O}(1\,{\rm min})$ runtimes per evaluation, requiring neither a Boltzmann hierarchy nor any fluid approximation, making parameter estimation with the DDM model numerically tractable. We also discuss the impact of DDM on cosmological observables, focusing on the case of two massive decay products. This work further establishes the integral-equation approach as a versatile and efficient framework for modeling non-cold relics in cosmological perturbation theory.
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All authors Nanoom Lee, Anna Bencke, Marc Kamionkowski, José Luis Bernal
High Energy Physics (Theory)
OPE = QNM
Paolo Arnaudo, Cristoforo Iossa, Robin Karlsson et al. (+1 more)
At microscopic scales the linear response of thermal states of large-$N$ CFTs is governed by a thermal operator product expansion (OPE), while at large scales response is governed by collective excitations known as quasinormal modes (QNM). We show that the OPE and QNM representations of the retarded correlator in mixed time and spatial momentum coordinates have an overlapping region of convergence in the complex time plane, giving a map between OPE and QNM data. We show that large-overtone QNM asymptotics are related to OPE singularities, while low-overtone QNM data appear in analytic continuation from short to large times. Using this approach we obtain new analytic results for QNM asymptotics, and numerically obtain low-overtone QNMs from OPE data for the Schwarzschild-AdS$_5$ black brane. We further show that the OPE spectrum is intimately related to QNM data through a set of sum rules which we derive in Mellin space. Finally, using the lightcone OPE, we argue that stress tensor correlators at large spatial momentum thermalise slower as the conformal
collider bounds approach saturation. This work points to a new thermal bootstrap programme where OPE and QNM data constrain each other.
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All authors Paolo Arnaudo, Cristoforo Iossa, Robin Karlsson, Benjamin Withers
Lattice Field Theory
TempLat: a versatile C++ engine for lattice field theories
Adrien Florio and Franz R. Sattler
We present TempLat, a C++ framework for
lattice field theory simulations in arbitrary dimensions. Its symbolic
language, built on expression templates, translates mathematical expressions almost verbatim into C++ while compiling to highly optimized kernels, in contexts ranging from classical-statistical to Monte Carlo simulations. TempLat is performance-portable: building on Kokkos, it supports large CPU clusters, as well as NVIDIA and AMD GPUs. Its abstraction of hardware into a device concept makes TempLat extensible to future architectures. We demonstrate excellent strong and weak scaling on both CPUs and GPUs. We also present ParaFaFT, a standalone parallel discrete
Fourier transform library supporting arbitrary dimensions on all of the above hardware, and
benchmark its scaling. Both are open source and available on GitHub, and power a new release of CosmoLattice, a widely used early-universe simulation library now available on GPUs.
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Quantum Physics
Fault-tolerant distributed quantum computing with a single nucleus per node
Yotam Vaknin, Shoham Jacoby, Roi Nevo et al. (+2 more)
Distributed
quantum computing interconnects small, high-quality nodes through optical links, but this architecture carries a pronounced asymmetry: in-node gates and measurements are cheap and high-fidelity, whereas inter-node communication relies on a low-coherence communication
qubit and faulty photonics. Previous approaches overcame the noisy link by placing several high-quality data
qubits in each node and consuming them for Bell pair and GHZ state
distillation. Here we show that
distillation can be avoided altogether. The key observation is that we can engineer a communication error bias, where photonic Bell pairs suffer frequent phase errors but only rare bit-flip errors. We design the syndrome-extraction
circuits so that this phase noise appears solely as a measurement error that does not propagate to the data
qubits, and is therefore suppressed by simply repeating the measurement; letting the error-correcting code itself, rather than a dedicated
distillation subroutine, to purify the link. This dramatically reduces the need for ancillary
nuclei: Floquet codes require only a single data
qubit per node, while general stabilizer codes require just one additional ancilla. We demonstrate high error-correction thresholds throughout this regime, and we identify
lattice surgery as inherently robust for this setting, enabling logical operations at a threshold close to that of
quantum memory. As a result, the performance of the
quantum computer is limited by the high-quality data
qubits, while the requirements on
photon indistinguishability and coherence of the communication
qubit are substantially relaxed.
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All authors Yotam Vaknin, Shoham Jacoby, Roi Nevo, Aleksander Kubica, Alex Retzker
Superconductivity
Probing nonlocal superconducting fluctuations with covariance noise magnetometry
Gustav Romare, Ilya Esterlis, Shimon Kolkowitz et al. (+1 more)
The nonlocal superconducting fluctuation corrections to the conductivity tensor $\sigma_{ij}(\mathbf{q},\omega)$ are calculated within the time-dependent Ginzburg-Landau framework, and their observable consequences for
quantum noise magnetometry are worked out. For a single nitrogen-vacancy (NV) sensor we obtain the relaxation rate $1/T_1$ as a function of temperature, sample-sensor distance, and probe frequency, identifying the scales at which the nonlocality and the dynamics of the pair fluctuations cut off the critical enhancement near $T_c$. For two-sensor covariance magnetometry we show that the two-point field correlator develops additional spatial structure whose range directly measures the fluctuation correlation length $\xi(T)$. We further analyze two channels that accompany the paraconductivity: the Maki-Thompson correction to the
spin susceptibility, and the fluctuation diamagnetism. Finally, we solve exactly, to all orders in a dc electric field and at all wave vectors, for the nonequilibrium current noise of the fluctuating film: the noise decouples from the nonlinear paraconductivity, violating the fluctuation-dissipation
theorem by universal factors at criticality and acquiring a bias-induced spatial anisotropy directly measurable by covariance magnetometry. The results are connected to a recent experiment measuring current noise near a thin film of BSCCO.
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All authors Gustav Romare, Ilya Esterlis, Shimon Kolkowitz, Alex Levchenko