High Energy Physics (Theory)
Thermal Double-Twist Data in Holography
V. Niarchos, C. Papageorgakis and A. Stratoudakis
We explain how to extract thermal OPE coefficients of double-twist operators in scalar two-point functions at infinite spatial volume from suitably regularized integrals of thermal response functions in momentum space. As a specific application, we implement the proposed approach to four-dimensional
holographic CFTs with an Einstein bulk action, where the finite-temperature state is captured by an AdS$_5$ black-brane geometry. In that case, the thermal response function can be computed on the gravitational side by solving numerically a radial ODE reduction of the Klein-Gordon equation. We obtain accurate values of double-twist data from this solution, completing previous
holographic and bootstrap studies of thermal two-point functions. Some of the reported
spin-resolved data that we compute are new.
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Quantum Physics
CryoZip: An Efficient Cryogenic Compressor for Quantum Error Correction Syndromes
Guanchen Tao, Alexander Knapen, Jacob Mack et al. (+4 more)
Scaling fault tolerant
quantum computing is increasingly constrained by the limited bandwidth and power budget across the 4 K to room temperature (RT) interface. We present CryoZip, a cross stack cryogenic compression framework that cooperates with a lightweight cryogenic
quantum error correction (QEC) predecoder to reduce 4 K to RT syndrome transmission under realistic,
circuit level noise. CryoZip targets sparse syndrome vectors with a sliding window compression architecture sized under strict decoding latency constraints to maximize energy efficiency. We implement and evaluate the design in 22 nm FDSOI characterized at 4 K, using vector based power, performance, and area analysis to obtain realistic hardware data. CryoZip achieves up to 48x compression, 1.8x higher than state of the art compressors, across various QEC codes while delivering 4 to 26x energy savings. When paired with a QEC predecoder, it yields over 14,238x bandwidth reduction, while energy savings rise to 42x when accounting for realistic QEC interface overheads.
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All authors Guanchen Tao, Alexander Knapen, Jacob Mack, Gokul Subramanian Ravi, Qirui Zhang, Mehdi Saligane, Dennis Sylvester
Astrophysics of Galaxies
A Census of the 200 Most Massive Galaxies Spectroscopically Observed with JWST at zspec $\sim$3-15
Mengyuan Xiao, Pascal A. Oesch, Longji Bing et al. (+26 more)
Massive
galaxies provide strong tests of
galaxy formation models, yet a comprehensive spectroscopic view of their properties and demographics in the early Universe has remained elusive. Here we present a JWST spectroscopic census of the 200 most massive
galaxies at zspec~3-15, selected using an evolving
stellar-mass threshold motivated by the
halo mass function and anchored at log(Mstar)>10 at z~5. These
galaxies represent the top 3% most massive systems among all publicly available prism observations. We derive their physical properties through joint SED fitting of spectroscopy and photometry, and construct a clean massive
galaxy sample after removing LRDs and broad-line AGN contaminants. We find that the massive
galaxy population evolves strongly with
redshift: normal SFGs (Av<1 mag) dominate at z>~6, while dusty SFGs (Av>1 mag) and QGs become more common toward lower
redshift.
Dust attenuation decreases systematically toward higher
redshift. We identify 29 massive QGs, including a population of recently quenched systems whose
star formation declined rapidly within the past ~100 Myr. We further show that both the traditional UVJ and recently proposed (ugi)s selections suffer substantial inconsistency with the most massive
galaxies at z>3, motivating a revised (ugi)s criterion calibrated using our spectroscopic sample. The inferred formation histories suggest at least two pathways toward quiescence: a
dust-enriched pathway linking normal SFGs, dusty SFGs, and QGs, and a more direct pathway connecting normal SFGs and QGs. Massive normal SFGs appear to grow through both relatively gradual and rapid assembly modes. Together, these results suggest that rapid
stellar-mass assembly,
dust enrichment, and quenching were already shaping the evolutionary pathways of the most massive
galaxies within the first billion years after the Big Bang.
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All authors Mengyuan Xiao, Pascal A. Oesch, Longji Bing, Rashmi Gottumukkala, Rui Marques-Chaves, Gabriel Brammer, Miroslava Dessauges-Zavadsky, David Elbaz, Songnan Qi, Anurag Amol Sawarkar, Manuel Aravena, Matthieu Béthermin, Rachel Bezanson, Rychard Bouwens, Caitlin Casey, Pieter van Dokkum, Andreas L. Faisst, Yoshinobu Fudamoto, Anna de Graaff, Olivier Ilbert, Garth Illingworth, Guilaine Lagache, Benjamin Magnelli, Jorryt Matthee, Yurina Nakazato, Daniel Schaerer, Sune Toft, Katherine E. Whitaker, Christina C. Williams
Earth and Planetary Astrophysics
The GAPS programme at TNG: LXXVI. TOI-1533: a compact system hosting a super-Neptune-mass pair with disparate radii
G. Mantovan, V. Nascimbeni, S. Desidera et al. (+49 more)
The present-day architecture of planetary systems contains information about their formation and migration histories. The origin of hot Jupiters (HJs, P $\lesssim$ 10 d, $R_{\rm p} > 8 R_\oplus$) has long been a matter of debate. While most of them are found to be “lonely”, there is a rare population of HJs hosting small companions on inner orbits (eight known as of May 2026). Their peculiar architecture suggests a gentle disc-migration mechanism. In this study, we present the discovery and characterisation of the multi-
planet system TOI-1533, comprising an inner sub-Neptune (TOI-1533 b, $P_{\rm orb} = 3.63$ d, $R_{\rm p} = 3.15 R_\oplus$) and an outer hot
giant planet (TOI-1533 c, $P_{\rm orb} = 8.06$ d, $R_{\rm p} > 7.5 R_\oplus$) with substantial H/He by mass ($\rho_{\rm p} < 0.48$ g cm$^{-3}$), both transiting an active K-
dwarf star ($T_{\rm eff} \approx$ 5130 K; $V$ (mag) $\approx$ 11). Our joint modelling of
stellar activity and planetary signals from radial velocities (HARPS-N) and transits (TESS) allows us to detect their Keplerian signals (approximately $10~\sigma$) and to isolate the
stellar modulation. The inclusion of simultaneous photometry in the multi-dimensional Gaussian processes formalism was a fundamental addition to the spectroscopic activity indicators, enabling the disentanglement of
stellar activity from planetary signals. The mass ratio of the two confirmed
planets ($M_{\rm b} / M_{\rm c}$ about 0.8), together with the super-Neptune mass of the large outer companion ($M_{\rm c} \approx 40 M_\oplus$), makes this system unusual compared to the other few HJs with low-mass inner companions.
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All authors G. Mantovan, V. Nascimbeni, S. Desidera, L. Malavolta, J. J. Lissauer, P. Leonardi, T. Azevedo Silva, C. Guerra, D. Polychroni, L. Borsato, M. Baratella, K. Biazzo, D. Nardiello, K. A. Collins, M. Damasso, J. De Leon, M. E. Everett, D. Gandolfi, S. Giacalone, L. Naponiello, G. Piotto, G. Scandariato, K. Stassun, S.W. Yee, L. Affer, F. Amadori, A. Bignamini, S. Colombo, M. D'Arpa, C. D. Dressing, A. Fukui, A. Ghedina, J. Higuera, K. Ikuta, Kawauchi, J. Korth, V. Lorenzi, L. Mancini, M. Mori, F. Murgas, N. Narita, E. Palle, H. Parviainen, A. Ruggieri, A. Savel, R. P. Schwarz, A. Shporer, G. Srdoc, Stockdale, D. Watanabe, R. Zambelli, T. Zingales
High Energy Physics (Theory)
As Cold as a Black Hole: Extended Photon Spheres
Marcos Riojas
It is widely believed that self-gravitating radiation cannot reach thermal
equilibrium with a black hole in asymptotically flat spacetime. We describe a marginally stable continuum exception to the standard instability argument. Our main observation is that the
photon sphere controls the Israel junction conditions (IJCs), the Tolman-Oppenheimer-Volkoff (TOV) equation, and finite-radius black hole thermodynamics: the IJCs and TOV equation are equivalent at zero radial pressure, the inverse specific heat at the
photon sphere is proportional to $-\Lambda$, and adding shells at fixed total mass lowers the asymptotic Hawking temperature if and only if the local specific heat is positive. Using these results, we show how to compute thermodynamic
entropies without the Euclidean path integral. The exception described here results from companion work with M.J. Strassler, where we found that a "hillingar black hole" (HBH) mimics an ordinary Schwarzschild black hole of mass $M$, sharing its Hawking temperature,
photon ring, and, in
equilibrium, its coarse-grained
entropy $S = 4 \pi M^2$. Here, we show these features are not tuned; they follow uniquely from joint mechanical and thermodynamic constraints. Conditions for thermodynamic mimicry and for the formation of extended
photon spheres are found; for self-similar solutions they coincide. A one-parameter family of self-similar systems – all of which, excepting the HBH, require massless walls at the edges of their extended
photon spheres – satisfies both conditions. This family includes "stiffest
stars" and "frozen
stars".
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High Energy Physics (Theory)
On Black Holes Surrounded by Radiation II: Thermodynamics
Marcos Riojas and Matthew J. Strassler
In a companion paper we considered a Schwarzschild black hole of mass $m$ enveloped by a thick "ocean" of massless particles that extends the black hole's
photon sphere into a region of finite depth. There we showed that this "hillingar black hole", of ADM mass $M$, optically mimics an ordinary black hole of the same mass. Here we find it also mimics the black hole thermodynamically: the formal assumption of thermal
equilibrium implies the system has the same temperature and
entropy as an ordinary black hole of mass $M$. We check this result carefully using multiple methods; a further method and indications of metastability are given by one of us in a companion paper. In AdS space, the mimicry does not hold, and the solutions have a richer structure. While it is far from clear that these systems are models for more realistic ones, we note possible connections with black hole
evolution. In particular, assuming thermal
equilibrium can be established and maintained, an HBH in a cavity of radius $\geq 3M$ can evaporate, potentially posing the information puzzle in a small finite volume.
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High Energy Astrophysical Phenomena
NLTE Spectral Modelling of the Nearby Stripped-Envelope Supernova 2024ehs
Wilmer Sand Hellman, Seán J. Brennan, Stan Bartmentloo et al. (+7 more)
We present a detailed study of the Type IIb
supernova 2024ehs, discovered in March 2024 in the nearby
galaxy NGC 3443 at a distance of $23.8\pm 0.9$ Mpc. Using photometric and spectroscopic observations spanning 10 months, we analyse its light curve, spectral
evolution, and physical properties with the SUMO radiative transfer code. SN 2024ehs exhibits a narrow light-curve peak, rapid decline, and weak helium lines, distinguishing it from typical Type IIb
supernovae. Comparisons with other objects, including SNe 1993J and 2020acat, and modelling of nebular spectra suggest a low ejecta mass, high velocities ($\sim$20,000 \kms), and a $^{56}$Ni mass just below $\sim0.1 \, \mathrm{M}_{\odot}$. Furthermore, the nebular spectral models indicate a progenitor with a helium core mass of $\sim 6 \, \mathrm{M}_{\odot}$, consistent with a zero-age main-sequence mass of $\sim 23\, \mathrm{M}_{\odot}$. The composition of spectra is explored through photospheric modelling, finding a link between expansion velocity and the relative strength of different element lines. This work discusses further the diversity of stripped-envelope
supernovae and the role of binary interactions for their progenitors, and demonstrates the need for further modelling to refine $^{56}$Ni mass estimates and to understand the physical mechanisms driving their
evolution.
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All authors Wilmer Sand Hellman, Seán J. Brennan, Stan Bartmentloo, Christoffer Fremling, Anjasha Gangopadhyay, Anders Jerkstrand, Ragnhild Lunnan, Josiah Purdum, Steve Schulze, Jesper Sollerman
High Energy Physics (Theory)
On Black Holes Surrounded by Radiation: I. Classical Considerations
Marcos Riojas and Matthew J. Strassler
We consider spherically symmetric static solutions to Einstein's equations describing a Schwarzschild black hole enveloped by a thick shell of orbiting massless particles with zero radial pressure. The orbiting gas is ultra-compact and ultra-relativistic, and can be viewed as the marginally stable limit of a stable Einstein cluster. These solutions, which we refer to as "hillingar black holes", extend the
photon sphere into a region of arbitrary depth. We compare these objects to black holes surrounded by other gases and note they have numerous special properties at the classical level; in particular, they appear optically indistinguishable from ordinary black holes to observers at infinity. We speculate concerning the possibility that these objects (or others much like them) might exist in nature, and whether they might be observable despite their similar outward appearance to ordinary black holes. We examine their thermodynamics and stability in companion papers.
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Earth and Planetary Astrophysics
High-resolution detection of reflected light from the exo-Neptune LTT-9779 b
F. Borsa
While high-resolution spectroscopy is routinely used to probe exoplanetary atmospheres, detecting reflected starlight remains highly challenging due to the extremely low
planet-to-
star optical flux ratios. We report the detection of reflected light from the ultra-hot exo-Neptune LTT-9779 b using high-resolution spectroscopy with ESPRESSO in its 4UT mode. By combining multiple epochs and applying a cross-correlation analysis with a theoretical reflection kernel, we were able to identify a faint signal matching the expected morphological and kinematic profile of the planetary reflection. This signature, whose presence has been detected at a signal-to-noise ratio of $\sim$5.4, exhibits a radial velocity semi-amplitude consistent with the expected orbital motion. We measured the
planet-to-
star flux ratio from the ratio of the equivalent widths of the planetary and
stellar cross-correlation functions, finding $F_{\mathrm{p}}/F_\star = 102^{+29}_{-30}$ ppm for the ESPRESSO 380–770 nm wavelength range. Assuming a Lambertian phase function, this corresponds to a
geometric albedo of $A_{\mathrm{g}} = 0.88 \pm 0.25$. The inferred albedo is consistent with previous space-based photometric measurements, suggesting a highly reflective atmosphere potentially dominated by scattering processes or high-altitude clouds. While we show that reflectivity is enhanced towards blue wavelengths, a detailed spectroscopic characterization of the planetary atmosphere from the reflected-light signal remains out of reach. This result highlights the scientific potential of future high-resolution spectrographs on extremely large
telescopes, paving the way for systematic reflected-light detections across a broader
exoplanet population, including cooler and smaller
planets.
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Astrophysics of Galaxies
JWST spectroscopy of galaxies at $z>10$: Damped Ly$\alpha$ absorbers reveal efficient star formation and hidden redshift biases
Kasper E. Heintz, Clara L. Pollock, Joris Witstok et al. (+23 more)
Recent observations with JWST have revealed a remarkable population of surprisingly luminous
galaxies at
redshifts $z>10$. Their abundance exceed predictions from simulations and empirical extrapolations from lower
redshifts, suggesting a transition in the physical conditions under which the first
stars formed. Here we investigate the physical conditions of a select sample of 25
galaxies with robust
redshift measurements at $z_{\rm spec}\geq 10$ observed with JWST/NIRSpec Prism. We characterize their
star-formation efficiency, `burstiness', and presence of strong rest-frame UV nebular lines in relation to the density of the local neutral atomic hydrogen (HI) gas reservoirs they are embedded in. We find that the prominence of strong rest-UV lines are correlated with the burstiness of the
galaxies, defined as ${\rm SFR_{10\,Myr} / SFR_{100\,Myr}}$. In contrast, there are no strong connections between the HI gas column density derived from the damped Ly$\alpha$ absorption (DLA) and the $M_{\rm UV}$ brightness, ${\rm SFR_{10\,Myr} / SFR_{100\,Myr}}$, and prominence of rest-UV lines. The most bursty
galaxies show a large variation in
star-formation efficiencies and HI gas surface densities, though typically with very short depletion timescales, $t_{\rm dep} \lesssim 20$\,Myr. This necessites rapid gas depletion times and external replenishment from infalling, pristine gas, powering starburst episodes on equally short timescales. We further quantify the impact of strong DLAs in
galaxy spectra on photometric and Ly$\alpha$-break
redshift-inferences, finding average
redshift biases of $\langle z \rangle =0.39$ and $0.14$, respectively, when not incorporating DLAs on the emergent spectra. We show the effect of this bias on new measurements of the
cosmic UV luminosity density, $\rho_{\rm UV}$, derived here at $z>10$, finding that this has a marginal impact on the UV luminosity function.
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All authors Kasper E. Heintz, Clara L. Pollock, Joris Witstok, Rychard J. Bouwens, Sandro Tacchella, Pascal A. Oesch. Pratika Dayal, Sownak Bose, Gabriel B. Brammer, Johan P. U. Fynbo, Rashmi Gottumukkala, Matthew J. Hayes, Akio K. Inoue, Benjamin Johnson, Harley Katz, Peter Laursen, Rohan P. Naidu, Desika Narayanan, Lucie E. Rowland, Nial R. Tanvir, Chamilla Terp, Sune Toft, Francesco Valentino, Fabian Walter, John R. Weaver, Arjen van der Wel, Mengyuan Xiao
Cosmology and Nongalactic Astrophysics
Numerical polology: towards next-generation model-building for cosmology
Will Barker, Will Handley, Michael Hobson et al. (+4 more)
The dark sector need not be restricted to simple field content. Indeed, simple bosonic configurations, such as scalar-tensor or dark
photon models, contrast with the much richer picture painted by many ultraviolet scenarios. Polology is the study of propagator poles, which correspond to particle states in any given theory. We outline a numerical polology framework for discovering perturbative, ghost-free models with consistent interactions, which produces theoretical model priors by sampling the coupling space. The method is tested on tensor field theories of up to rank three. Subsequent observational constraint pipelines are illustrated for black hole superradiance (M33 X-7), dynamical dark energy (DESI DR2, Pantheon and SH0ES) and gravitational waves (GWTC-3).
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All authors Will Barker, Will Handley, Michael Hobson, Anthony Lasenby, Carlo Marzo, Alessandro Santoni, Leonardo Torcellini
Mesoscale and Nanoscale Physics
Critically Enhanced Magnon Transport in Low-dimensional Magnets
Ping Tang
Transport properties of (quasi)particles in condensed matter depend profoundly on the spatial dimension. Motivated by recent advances in growing ultrathin
magnetic films and monolayer van der Waals magnets, we present a theory of
magnon transport in
magnetic films spanning the crossover from bulk to the two-dimensional (2D) limit. We find a
magnon conductivity that diverges~logarithmically in magnetically soft but stable (quasi)2D magnets with long-range dipolar interactions. This critical enhancement is absent in bulk systems and may explain the unusually large
magnon conductivities recently observed in ultrathin yttrium iron garnet films. Our results reveal an intrinsic mechanism for enhanced
magnon transport in low dimensions and highlight the potential for engineering high-efficiency
magnon conductors in atomically thin magnets.
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High Energy Physics (Phenomenology)
A Levitated-Magnet Vector Force Sensor for Spin-Dependent Exotic Interactions
Dorian W. P. Amaral, Lei Cong, Tim M. Fuchs et al. (+2 more)
We present a magnetically levitated
ferromagnetic vector force sensor that enables selective searches for
spin-dependent exotic interactions mediated by beyond-Standard-Model
bosons. A defining feature of
spin-dependent exotic interactions is that they can generate forces with distinct directional signatures set by the relative
spin configuration of the interacting bodies. We show that our sensor resolves these signatures by mapping forces along different axes onto distinct translational modes with different resonance frequencies, thereby separating interaction channels within the same coupling class. As a representative example, we study parity-violating axial-vector–vector interactions mediated by a
spin-1 $Z'$
boson between a sensing and a driving levitated ferromagnet. Using a matched-filter likelihood analysis, we show that a setup based on an already demonstrated experiment can probe the pure electron–electron coupling $g_A^e g_V^e$ in the previously inaccessible force range $\lambda \lesssim 1\,\mathrm{cm}$, corresponding to mediator masses $M_{Z'} \gtrsim 10^{-5}\,\mathrm{eV}/c^2$. Our results establish levitated ferromagnets as a promising platform for millimeter-scale searches for
spin-dependent fifth forces and for resolving the multiple effective potentials associated with a given coupling class.
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All authors Dorian W. P. Amaral, Lei Cong, Tim M. Fuchs, Hendrik Ulbricht, Dmitry Budker
Chemical Physics · Cross-listed from cs.LG
ReactionAtlas: Ab origine exploration of chemical reaction networks with machine learning
Stefan Gugler, Max Eissler, Khaled Kahouli et al. (+1 more)
Mapping a chemical reaction network, the graph of minima and transition states (TS) and the elementary reactions connecting them, is the natural
language of chemistry, from catalysis to combustion to the origin of life. Constructing such a reaction network for a given chemistry has been impractical: it requires finding and characterizing tens of thousands of TS, a task for which traditional methods such as density functional theory (DFT) are typically prohibitively slow and require reactant and product as input. We introduce ReactionAtlas, which builds a reaction network $\textit{ab origine}$ from a handful of seed molecules and without hand-crafted rules. Specifically, our machine-learned generative model proposes reactions from kinetically sampled candidate compounds and a DFT-trained machine learned force field (MLFF) filters them to valid TS, the resulting products of which enter the search as new seeds. Starting from eight pre-biotic seeds (CH$_2$O, H$_2$O, OH$^-$, H$_3$O$^+$, CO$_2$, H$_2$CO$_3$, HCO$_3^-$, H), ReactionAtlas discovers $\sim$47,000 reactions among $\sim$12,000 compounds. The MLFF TSs match the PBE0 references within 0.5 Å RMSD in 85% of the cases and can be easily brought to the PBE0 level. Thus, ReactionAtlas maps small carbohydrate chemistry up to C$_4$H$_8$O$_4$ at unprecedented scale and accuracy, including charge and stereo information. It enables novel insights into many well-studied reaction paths, including the formose cycle, which we highlight for its centrality to the chemical origins of life. Notably, our framework also allows establishing alternative reaction pathways for formose chemistry.
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All authors Stefan Gugler, Max Eissler, Khaled Kahouli, Klaus-Robert Müller
Quantum Physics
Diffusion-warm sampling of the XY model enables fast thermalization at scale
Sehmimul Hoque, Roger Melko and Pooya Ronagh
We introduce a novel technique for scalable sampling of
spin-system states with continuous
symmetries using
diffusion models. By applying our approach to the XY model, a fundamental continuous-
spin model in condensed matter physics, we show that our technique addresses the shortfalls of the Markov chain Monte Carlo (MCMC) in generalization to varying system sizes. More specifically, we show that training a temperature-conditioned
diffusion model on smaller-size XY model
lattices enables the generation of accurate samples in larger
lattice sizes. By tracking physically important observables of the model, such as
spin correlations, our experiments demonstrate that
diffusion sampling followed by a few MCMC steps reduces the thermalization time by an order of magnitude relative to the standard MCMC with random initialization. Our study provides valuable insight as to how generative models can be used to study continuous-state condensed matter systems at scale.
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High Energy Physics (Phenomenology)
A Geometric Framework for CPT Violation in Neutral Meson Mixing Using Biorthogonal Bargmann Invariants
Swarup Sangiri
We develop a
geometric framework for characterizing CPT violation in neutral
meson systems using Bargmann invariants formulated within a biorthogonal description of the non-Hermitian effective
Hamiltonian governing neutral
meson mixing. Interpreting CPT violation as a relative
geometric deformation of the heavy- and light-state mixing directions in projective
flavor space, we construct a fourth-order Bargmann invariant together with its CP-conjugate counterpart involving the physical mass eigenstates and experimentally accessible decay channels. From the phase of a rephasing-invariant product of these invariants, we define a
geometric observable that isolates the CPT-violating contribution. The resulting formalism identifies the channel dependence of the
geometric response and yields a selection criterion for decay-mode combinations exhibiting linear sensitivity to CPT violation. We further relate the
geometric deformation to the Lorentz-violating coefficients of the Standard-Model Extension, showing that the resulting observable inherits the characteristic sidereal modulation of the SME framework. The present work provides a complementary
geometric perspective on CPT violation in neutral
meson mixing and establishes a foundation for future phenomenological studies of
geometric signatures of CPT and Lorentz violation.
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Quantum Gases
Density Wave Ordering with Disordered Ultracold Fermions in Optical Cavities
Óscar Rios Alves, Filippo Ferrari, Lorenzo Fioroni et al. (+2 more)
We investigate the interplay between cavity-induced density-wave ordering and controllable disorder in a trapped two-dimensional gas of ultracold
fermions. The atoms are dispersively coupled to an optical cavity and transversely driven by a pump beam, while an additional speckle beam spatially modulates the atom-light coupling through an AC-Stark shift of the atomic transition. In momentum space, this disorder converts the usual coupling between the cavity mode and a discrete set of density-wave
Fourier components into a coupling to a continuum of fermionic density modes, weighted by the spectrum of the speckle pattern. Using linear response theory, we derive the superradiant threshold and show that the disordered interaction renormalizes the effective light-matter coupling, lowering the critical pump strength on average, with the threshold becoming self-averaging for short speckle correlation lengths. We complement this analysis with a numerical mean-field treatment that gives access to the intracavity
photon number and to the real-space
fermion density across the transition. These results confirm that the disorder shifts the photonic phase boundary and, above threshold, distorts the density-wave
crystal by populating
Fourier components beyond those selected by the clean cavity geometry. Our findings identify both the emitted cavity light and in situ density images as probes of engineered disorder in fermionic matter coupled to optical cavities.
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All authors Óscar Rios Alves, Filippo Ferrari, Lorenzo Fioroni, Alberto Mercurio, Vincenzo Savona
High Energy Physics (Phenomenology)
Toponium effects on quantum steering and Bell nonlocality of top quarks
J. A. Aguilar-Saavedra and S. Rodríguez-Benítez
We investigate
quantum steering and Bell nonlocality in top-
quark pair production at the LHC near threshold. The toponium contribution strengthens the
spin-singlet component and substantially enhances the
entanglement between the two
quark spins. With current LHC data,
quantum steering appears observable with a statistical significance around $10\sigma$. For Bell nonlocality, the statistical significance can also be high close to threshold, reaching about $9\sigma$, although the feasibility of such a measurement will depend crucially on the control of systematic uncertainties.
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Superconductivity
Unconventional superconductivity in $A$V$_2X_2$O family of surface altermagnets
M. Franz
Motivated by the recent discovery of superconductivity at 16.3 K in layered oxychalcogenide Na$_{2-x}$V$_2$Se$_2$O we investigate pairing instabilities in the broader family of layered materials composed of V$_2$O planes, believed to exhibit altermagnetic order in their monolayer form. Even though the bulk family members KV$_2$Se$_2$O and Rb$_{1-\delta}$V$_{2}$Te$_{2}$O are likely conventional antiferromagnets that show only surface altermagnetism, our analysis predicts exotic equal-
spin triplet superconductivity as the dominant pairing instability in these materials. This is a consequence of their unique
magnetic and sublattice structure that renders electron bands incompatible with conventional
spin-singlet pairing. The predicted triplet superconducting phases are topologically non-trivial and capable of supporting
spin-polarized persistent currents, properties potentially useful in technological applications.
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Quantum Physics
Deep Reinforcement Learning for Individual Atomic Control and Cooling
Matthew L. Peters, Guoqing Wang, David C. Spierings et al. (+5 more)
Real-time feedback control of
quantum systems is often limited by partial observations, nonlinear dynamics and measurement noise, which make accurate model-based controllers difficult to design. Here we show that deep reinforcement learning can cool the motion of a single neutral atom coupled to a high-finesse optical cavity using only the continuously monitored cavity transmission. We first train the controller in simulation and then transfer it to the experiment, where online fine-tuning adapts it to unmodeled experimental dynamics. The learned policy damps the atom's motion in real time and achieves a cooling time constant of 388 +/- 14 microseconds, corresponding to only two motional periods in the trap. It also outperforms a standard linear differentiator controller in cooling speed while maintaining comparable atom retention over a broad range of operating conditions. These results establish reinforcement learning as a practical strategy for feedback control in
quantum-limited experiments where compact analytical models are incomplete.
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All authors Matthew L. Peters, Guoqing Wang, David C. Spierings, Niv Drucker, Meng-Wei Chen, Audrey Bartlett, Isaac Chuang, Vladan Vuletić
High Energy Astrophysical Phenomena
Filippo D'Ammando
Identifying the sources of the high-energy astrophysical
neutrinos has been one of the main topics in astrophysics since the first observation of high-energy
neutrinos by the IceCube
Neutrino Observatory. Active
Galactic Nuclei (AGN) are sources of high-energy gamma-rays and are considered to be promising candidates to be sources of high-energy
neutrinos and ultra-high energy
cosmic rays as well. However, several studies suggest that the
neutrino emission from the $\gamma$-ray blazar population only accounts for a small fraction of the total astrophysical
neutrino flux. We present and discuss recent results on the search for correlations between astrophysical
neutrinos and both gamma-ray and
radio bright AGN. The IceCube Collaboration has reported high-energy
neutrino events that may come from both the
radio-loud AGN TXS 0506+056 and the
radio-quiet AGN NGC 1068. Other cases of possible associations between high-energy
neutrino events and individual blazars were claimed with controversial results. We discuss the properties of these sources together with the different
neutrino production mechanisms proposed for those sources. Finally, we outline future prospects in the field, focusing on remaining open questions, the development of upcoming
neutrino facilities, and the evolving multi-frequency landscape within the multi-messenger era.
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Astrophysics of Galaxies
A SHARP Look at Quenching and Bulge-Disk Growth in Massive Galaxies at Cosmic Noon
Chiara Mancini, Adriana Gargiulo, Alvio Renzini et al. (+11 more)
The physical mechanisms that quench
star formation in massive
galaxies remain poorly understood. At
cosmic noon (1<z<3), when
star formation and AGN activity peak,
galaxies rapidly evolve from
star-forming disks into quiescent, bulge-dominated systems. While quenching correlates with
stellar mass and bulge growth, the causal link between bulge assembly,
star-formation suppression, and feedback processes remains unclear.
Stellar population analysis from spatially resolved spectroscopy of
galaxies caught during quenching is crucial to advance on this issue. We show that the SHARP-VESPER Integral-Field Spectrograph (IFS) can efficiently fill this gap by combining ELT-class sensitivity, 31 mas spatial resolution (>3x sharper than JWST) and broad near-IR wavelength coverage with 12-IFU multiplexing. This will enable, for the first time, a simultaneous bulge-disk decomposition of
stellar populations and spatially resolved mapping of ionised gas in massive
galaxies (log $M_*/M_{\odot}\geq 11$) at 2.2<z<3.5, targeting systems on the main sequence shortly before quenching or already in the green valley. With typical exposure times of 15 hr, we will obtain S/N>15-20 per spectral resolution element, on the inner bulge, and outer disk extracted spectral continuum, and S/N>5 for nebular lines ([OII], H$\beta$, [OIII], H$\alpha$) on sub-kpc scales. These observations will allow us to reconstruct independent bulge and disk
star-formation histories, ages,
metallicities, and $\alpha$-enhancements, while mapping spatially resolved
star formation, gas kinematics, and feedback-driven
outflows. By directly comparing the timing of bulge growth and
star-formation suppression across
galaxy components, this programme will test whether quenching proceeds inside-out, distinguish fast and slow quenching pathways, and link structural transformation to feedback processes in the most massive
galaxies at
cosmic noon.
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All authors Chiara Mancini, Adriana Gargiulo, Alvio Renzini, Emanuele Daddi, Stefano Zibetti, Fabio R. Ditrani, Anna R. Gallazzi, Susanna Bisogni, Paolo Franzetti, Giustina Vietri, Louis Gabarra, Fabrizio Gentile, Marcella Longhetti, Marco Scodeggio
Statistical Mechanics
Athermality of generalized Gibbs ensembles
Riccardo Senese, Bruno Bertini, Katja Klobas et al. (+1 more)
Integrable
quantum systems evolving from non-
equilibrium initial states do not thermalize to conventional Gibbs ensembles (GE). Instead, at long times they relax to generalized Gibbs ensembles (GGEs), which incorporate the full set of local and quasi-local conserved quantities. While GGEs have been extensively studied in the literature, a quantitative analytic characterization of how different they are from ordinary GEs is still lacking. In this work, we address this question by employing the concept of athermality, which we define within
quantum resource theory as the relative
entropy between a given state and the closest thermal state. By means of integrability techniques we compute the athermality for several
quantum quenches in paradigmatic integrable models, including the free XY
spin chain, the interacting Lieb-Liniger model, the XXZ
spin chain, and the harmonic chain. We find that often the athermality becomes anomalously small when the post-quench
Hamiltonian is critical in its ground state, despite probing physics at a finite energy density. We also prove that it systematically develops a singularity at criticality, which is inherited from the
entropy of the GGE.
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All authors Riccardo Senese, Bruno Bertini, Katja Klobas, Pasquale Calabrese
Quantum Physics
Improving the loss threshold for quantum advantage in photonic sensors by complete photon counting
Gerard J. Machado, Yazeed K. Alwehaibi, Guillaume Thekkadath et al. (+9 more)
Tolerance to imperfections is a defining performance criterion for
quantum sensors. The threshold for achieving a
quantum advantage depends on the input state, sensor configuration, detection scheme, and, critically for optical platforms,
photon loss. We consider a nonlinear interferometer in which two gain-optimized parametric nonlinear optical processes couple the state to the internal sensor and subsequently mix the reference and sensor beams. We demonstrate that measuring the full
photon-number output statistics of this setup yields marked improvements in the loss threshold. Using
photon-number-resolving detection (PNRD) based on transition-edge sensors (TESs), we experimentally reconstruct the joint
photon-number statistics at the interferometer output. Subject to internal and external losses of approximately 25 % and 45 %, respectively – and without any post-selection or loss correction – we observe an unconditional violation of the shot-noise limit by $2.37 \pm 0.11$ dB. This translates to a 44 % enhancement in estimation precision over conventional click-detection strategies. We verify this performance by evaluating the classical Fisher information against both an analytical model of the joint
photon-number distribution and the raw measured statistics. Ultimately, our results demonstrate that combining nonlinear interferometry with PNRD unlocks metrological information fundamentally inaccessible to click detectors, establishing a clear path toward practical,
quantum-enhanced sensing under realistic loss conditions.
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All authors Gerard J. Machado, Yazeed K. Alwehaibi, Guillaume Thekkadath, Zhenghao Li, Aonan Zhang, Shang Yu, Adriana E. Lita, Richard P. Mirin, Martin J. Stevens, Juan P. Torres, Raj B. Patel, Ian A. Walmsley
High Energy Physics (Phenomenology)
Rich Phenomenology from Simple Ingredients: A Review of Confining Dark Sectors
Pouya Asadi, Austin Batz and Graham D. Kribs
We review theories with confining dark sectors and their implications for dark matter, cosmology, phenomenology, and unsolved Standard Model puzzles. Models with new strongly-coupled non-Abelian gauge interactions can lead to a variety of dark matter candidates (dark
mesons,
baryons, glueballs, etc.), as well as mechanisms to generate its abundance and
symmetries that explain its stability. There are also many potential discovery channels, including direct detection, indirect detection, astrophysical observables, and
colliders, as well as correlations between different experiments. We compile a broad conceptual overview of the literature on this topic, aimed at both theorists looking for which questions remain unanswered and experimentalists looking for novel search opportunities. While the theoretical landscape is vast, there are both unifying features and calculational techniques that apply to various regimes. We particularly highlight applications to explaining the similarity of visible and dark matter energy densities, i.e. the $abundance~similarity~puzzle$. We advocate further exploration of this class of theories in the effort to uncover physics beyond the Standard Model.
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High Energy Physics (Phenomenology)
Kun Cheng, Tao Han, Guanghui Li et al. (+1 more)
Photon pairs have provided an ideal laboratory for exploring
entanglement and Bell inequality violation in low-energy experiments. Extending such studies to high-energy
colliders is of great interest but has yet to be explored. Exploiting the
photon conversion process for nearly on-shell
photons, we formulate a factorization framework and an effective two-
qubit description, which enable access to
quantum information encoded in
photon pairs. Using the existing Belle data set, we estimate that a $7.4\sigma$ violation of the Bell inequality could be achieved. The same framework can also probe
quantum discord and nonstabilizerness, which could be measured with precisions of 5.6% and 1.6%, respectively. All the reconstructed results from
photon conversion in the two-
qubit framework are found to be consistent with the kinematic approach of real
photons, and the formalism can apply to other
spin-1 systems in an appropriate two-
qubit limit.
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All authors Kun Cheng, Tao Han, Guanghui Li, Bin Yan
High Energy Physics (Phenomenology)
The effect of nuclear recoil on neutrino oscillations: Toward understanding of short baseline anomalies
Luca Parini and Eugene V. Stefanovich
We studied the structure of the
neutrino wave functions produced in
nuclear decays, with particular emphasis on the role of
nuclear recoil. Although the fraction of the
recoil energy associated with a nonzero
neutrino mass is extremely small, it gives rise to a notable time-dependent
flavor oscillation. For long-lived sources, such as those used in gallium anomaly and reactor anomaly experiments, this
recoil-driven oscillation makes a substantial contribution to the observed deficit of (anti)
neutrinos.
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Astrophysics of Galaxies
Unveil the nature of JWST-AGN and Little Red Dots with SKAO continuum surveys
Giovanni Mazzolari, Dharam V. Lal, Isabella Prandoni et al. (+6 more)
The advent of JWST has revealed a large population of AGN at $z>4$, which are $\sim1$ dex more abundant than previously expected, including also the enigmatic population of Little Red Dots (LRDs). Remarkably, the vast majority of JWST-discovered AGN and LRDs are not detected in X-rays, and most of them also show faint rest-frame UV continua and faint high-ionization emission lines, as well as unusually faint emission in the Mid and Far infrared. Recent studies investigating their
radio properties have reported no significant detections, even in deep stacking analyses, reaching sensitivities of 0.5-0.1 $\mu$Jy at $z\sim 5-6$, corresponding to $L_{R}\lesssim 10^{39}\rm \ erg\ s^{-1}$. While these non-detections may be consistent with a standard
radio-quiet nature, some results suggest that the
radio emission might instead be significantly suppressed by other physical phenomena. Three main scenarios have been proposed in the literature to explain the physical properties of these objects across the electromagnetic spectrum: Compton-thick absorption by a broad-line region with high covering-factor, intrinsically weak emission driven by high
accretion rates, or the presence of a cocoon of dense ionized gas that produces strong scattering effects. The unprecedented sensitivity of SKAO will enable the detection of the
radio emission of these AGN in all three cases. Because each scenario is expected to produce distinct
radio signatures, future SKAO continuum surveys will be able to distinguish between them, uncovering the physical processes responsible for their peculiar properties. Observations spanning a wide range of integration times (1-1000 hours) and frequencies with SKA-Mid and SKA-Low (0.2-11 GHz) will allow us to characterize these objects from the local Universe to high
redshift, investigate possible
radio variability, and test alternative scenarios to black hole
accretion.
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All authors Giovanni Mazzolari, Dharam V. Lal, Isabella Prandoni, Roberto Gilli, Roberto Maiolino, Hannah Übler, Ivan Delvecchio, Marcella Brusa, Marco Mignoli
Solar and Stellar Astrophysics
Parameterizing the Standing Accretion Shock Instability for Inference with Galactic Supernova Neutrino Signals at IceCube
Dwaipayan Mukherjee, Mohamed Rameez and Basudeb Dasgupta
Simulations of core-collapse
supernovae have revealed an epoch of hydrodynamic instability in which the matter of the collapsing
star undergoes quasi-periodic oscillations, known as the standing
accretion shock instability (SASI).
Neutrinos produced in the core of the
star travel through this oscillating matter, and information about this epoch is encoded in their high-statistics event rate observable at
neutrino observatories. We propose a parametrization of the SASI-modulation to study its broad features, enabling statistical inference of SASI parameters. For the
benchmark Galactic supernovae considered, we show that IceCube can identify this epoch of instability and reconstruct its parameters with precision at the sub-percent level for the SASI frequency, percent level for the peak time, and a few to ten percent level for the amplitude and duration.
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High Energy Astrophysical Phenomena
Prospects for Improving the Theoretical Uncertainty for Tests of General Relativity with the EHT
Lia Medeiros, George N. Wong and Feryal Ozel
We characterize the relationship between the size of the bright ring observed in simulated black hole images and the size of the analytic black hole shadow. Calibrating this relationship is crucial for mass measurements and, when independent mass measurements are available, for tests of general relativity using Event Horizon
Telescope (EHT) images. We perform this calibration using a large set of high-resolution simulated images generated with different
accretion-flow modeling approaches and spanning a wide range of system parameters and initial conditions. We show that the theoretical uncertainty in this relationship can be reduced significantly through future observations, improved imaging techniques, and the application of astrophysical or model-based constraints. In particular, the uncertainty decreases compared to existing measurements when (i) observing at 345 GHz, (ii) applying
geometric image constraints, such as the ring width inference from the PRIMO image reconstruction
algorithm, (iii) incorporating astrophysical constraints such as the black hole
spin axis in M87 being aligned (or anti-aligned) with the large-scale jet observed at longer
radio wavelengths, and (iv) assuming that the
accretion flow can be described by a magnetically arrested field configuration. Finally, we quantify how the uncertainty is expected to decrease as additional observations are obtained in subsequent years and identify dwell-time filtering, i.e., evaluating the persistence of a
geometric measurement over time, as a promising avenue for improving the precision of the calibration.
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