We investigate the interplay between thermodynamic phase transitions and the dynamical behavior of quasinormal modes (QNMs) in weakly nonlinear charged anti-de Sitter black holes. In a nonextended phase space, we identify a reentrant large-small-large(intermediate) phase transition for these black holes. Employing the shooting method to solve the Klein-Gordon equation for a massless scalar field, we compute QNM frequencies across these phases, revealing distinct behaviors in different phases. Specifically, to the best of our knowledge, this is the first report of utilizing QNMs as dynamical probes of thermodynamic phases during reentrant phase transitions including zeroth and first-order transitions. These findings establish QNMs as a powerful dynamical probe for thermodynamic phase transitions, providing new insights into the thermodynamic and dynamical properties of nonlinear charged black holes as well.

The Weyssenhoff fluid expands the ordinary perfect-fluid description of general relativity by taking into account the intrinsic spin of its constituent particles. Within the linearized regime of Einstein-Cartan theory, we investigate the exterior geometry produced by isolated slowly rotating Weyssenhoff fluids, i.e., sources endowed with both macroscopic and microscopic angular momenta. Our work represents an extension of the foundational analysis of Arkuszewski, Kopczyński and Ponomariev, which was restricted to the static fluid configuration. Under the assumptions of stationarity and axial symmetry, we derive the explicit expression for the linearized stress-energy tensor of the source and obtain the corresponding metric through a multipole expansion. The ensuing solution exhibits a generalized Lense-Thirring structure, with both the gravitoelectric and gravitomagnetic sectors affected by the quantum spin and macroscopic rotation. We also discuss some phenomenological implications of the model, including the gyroscope precession and the Sagnac effect, along with potential experimental probes of the predicted corrections.

We build an ultralight dark matter model with repulsive self-interactions, starting from a five-dimensional action that only includes a $U(1)$ gauge field and several massive and charged free fermions. The dark matter scalar field corresponds to the fifth component of the gauge field, after compactification to four dimensions. Although the single-fermion case only leads to attractive self-interactions, two fermions can already give rise to repulsive self-interactions, thanks to a Scherk-Schwarz twist around the fifth dimension. We check the observational and theoretical self-consistency of this scenario, from the inflation stage to the current time. We find that large ranges of model parameters are allowed. For scalar masses below ${10}^{-12}\mathrm{eV}$ the self-interactions are negligible and the model behaves as fuzzy dark matter. For higher masses the repulsive self-interactions govern the formation of solitons of astrophysical size. Larger sizes require a large initial misalignment or small masses in the fuzzy dark matter regime.

The spherical Fourier-Bessel (SFB) basis, in separating the angular and radial modes of the power spectrum, permits a targeted identification and mitigation of systematics in clustering surveys while retaining more cosmological signal than traditional bases. We demonstrate this principle on the eBOSS DR16 luminous red galaxy (LRG) and quasistellar object (QSO) samples, identifying modes which may be contaminated by systematics. Our initial inference on the LRG sample yields an $f_{\mathrm{NL}}$ value consistent with zero, while the QSO value is in slight tension with zero. Using the SFB basis, we vary the selection of angular and radial modes to search for inconsistencies in the inferred value of $f_{\mathrm{NL}}$, an indicator of underlying systematics. In the QSO sample, we find evidence ($p\lesssim 0.002$ compared to the same cuts on EZMocks) of a systematic afflicting large physical scales, which is consistent with residual stellar contamination; we also find evidence for an unknown systematic in the QSO sample ($p=0.01$), with consistent but less significant evidence in the LRGs ($p\approx 0.06$), at the approximate angular plate and imaging scale of eBOSS.

Gravitational-wave detectors such as LIGO, Virgo, and KAGRA are highly sensitive instruments susceptible to numerous noise sources. Short-duration transient noise events, known as glitches, pose a particular challenge for data analysis pipelines as they can mimic or obscure astrophysical signals. We present GlitchGAN, a class-conditional generative model, built upon the conditional derivative GAN (cDVGAN) architecture, that is capable of synthesizing glitches directly in the time domain. The model is trained on high-quality reconstructions of seven common glitch types observed during LIGO’s third observing run (O3): blip, fast scattering, koi fish, low-frequency burst, scattered light, tomte, and whistle. We show that GlitchGAN generalizes effectively, learning to reproduce a diverse glitch space that is consistent with these reconstructions. Moreover, because the model is conditioned on glitch class, it can generate hybrid or transitional glitch morphologies by interpolating across the class-conditioning vector after training. GlitchGAN generates 1000 glitches in under 22 seconds on a CPU, making it suitable for large-scale glitch synthesis for detector simulations, mock data challenges, and pipeline validation. Synthetic glitches are validated against real glitch reconstructions using the Gravity Spy classifier, widely used in the GW community for glitch classification, and an unsupervised analysis using UMAP embeddings. Gravity Spy classifies the majority of GlitchGAN’s synthetic glitches as the correct class while the UMAP analysis shows substantial overlap between real and synthetic samples in the reduced latent space. To investigate residual distributional differences between real glitches unseen during training and generated synthetic glitches, we train a separate holdout GlitchGAN model on nearly the same dataset but with a small held-out split, and use a downstream convolutional neural network to distinguish these held-out real glitches from synthetic glitches produced by the holdout model. While this classifier reliably detects synthetic samples in a clean, noise-free representation, this detectability drops substantially once real and synthetic glitches are injected into realistic detector noise, the condition under which synthetic glitches would typically be deployed for downstream applications. Despite remaining statistically distinguishable, we show that GlitchGAN-generated glitches are practically useful: augmenting real training datasets with synthetic samples matches simple duplication of the same real data when data is abundant, and increasingly outperforms it as real data becomes scarcer. Finally, we highlight a critical limitation of magnitude-only spectrograms: classifiers operating on magnitude $Q$-transforms can confidently misclassify physically unrealistic glitches from less robust models, underscoring the need for complementary validation methods that preserve phase information.

Quantum chromodynamics (QCD) at finite density is most often formulated on the lattice as a grand canonical ensemble. Since lattice QCD has a complex action problem at finite baryo-chemical potential (${\mu }_B$), its results at finite density are indirect: e.g. in the form of a set of expansion coefficients. In contrast, the canonical formulation offers direct results for integer-valued net-baryon number. In this work we present for the first time results in the canonical formulation with physical quark masses. To this end we use a high statistics finite-volume lattice (${16}^3\times 8$) dataset that we generated at ${\mu }_B=0$ with our 4HEX staggered action. We extend the canonical ensemble to noninteger net-baryon number and connect the results back to the grand canonical ensemble. Unlike reweighing to real ${\mu }_B$, this method can also be used with rooted staggered quarks. For densities where the sign problem can be overcome by brute force computing power, this scheme provides lattice QCD results (e.g., for pressure, baryon density) directly, without relying on any extrapolation in the baryo-chemical potential. In this work we chart the phase diagram by studying bulk thermodynamic observables, which we show to be feasible up to ${\mu }_B\approx 500\mathrm{MeV}$.

Quantum algorithms are a promising framework for unfolding the causal configurations of multiloop Feynman diagrams, which is equivalent to querying the directed acyclic graph (DAG) configurations of undirected graphs in graph theory. In this paper, we present a quantum algorithm for querying in both types of applications, using a systematic and sparing logic in the design of an oracle operator. The construction of the quantum oracle is based exclusively on multicontrolled Toffoli (MCX) gates and quantum NOT (Pauli-$X$) gates. The efficiency of the algorithm is evaluated by comparison with a quantum algorithm based on binary clauses. Furthermore, we analyze the impact of traspilation and introduce an appropriate metric to assess the complexity of the algorithm, the quantum circuit area. We explicitly analyze three-, four- and five-eloop topologies, which have not previously been explored due to their higher complexity and the current limitations of quantum simulators.

In the present study, we extend our previous analysis of the proton electromagnetic form factors (FFs) extracted from exclusive photon leptoproduction (EP) measurements in kinematic regions where the Bethe-Heitler (BH) process dominates the cross section by including all currently available high-precision EP data from CLAS and Hall A Collaborations. Using the same phenomenological framework, we investigate the consistency among the different datasets, determine the proton electromagnetic FFs within several fitting scenarios, and extract the corresponding charge and magnetic radii. A significant tension is found between the CLAS 2018 measurements and the remaining EP data, with the low-$|t|$ region playing a dominant role in this tension. We systematically investigate this behavior through $|t|$-cut scans and assess its impact on the extracted FFs and radii. For all analyses, the extracted proton charge radius is smaller than the Particle Data Group average and most determinations based on elastic electron-proton scattering. However, the results are consistent, within uncertainties, with the PRad measurement and muonic hydrogen spectroscopy. In contrast, the magnetic radius is found to be compatible with the current world average. These results demonstrate that BH-dominated EP measurements provide an independent and complementary approach to determine the electromagnetic structure of the proton and offer additional support for the small-radius solution of the proton charge-radius puzzle.

Particle dark matter scattering on electrons in the Sun may gravitationally capture and self-annihilate inside it to neutrinos and antineutrinos or other final states that in turn decay to them. Using up-to-date Super-Kamiokande measurements of atmospheric electron-type and muon-type neutrinos fluxes, we set the most stringent limits on the electron scattering cross sections for leptophilic dark matter, annihilating to $\nu \overline{\nu }$ and ${\tau }^{+}{\tau }^{-}$ with 100% branching ratio, over mass ranges of $\sim 5–100$ and $\sim 15–100\mathrm{GeV}$, respectively. These limits excludes cross sections down to about ${10}^{-40}–{10}^{-39}{\mathrm{cm}}^2$ which outdo direct searches for dark matter-electron scattering and previously set limits at IceCube. We also derive corresponding reaches at Hyper-K and show that atmospheric neutrino observations restricted to the direction of the Sun can improve sensitivities.

We prove the robustness of the analytic approximation used in (hybrid) loop quantum cosmology to compute the primordial power spectrum of the cosmological perturbations for a recently proposed vacuum state (the nonoscillatory state with asymptotic Hamiltonian diagonalization). To investigate this, we study different approximations to the effective mass of these perturbations near the bounce, showing that the Pöschl-Teller potential employed in previous works leads to indistinguishable power spectra compared to other estimations of the mass, provided that they successfully capture the characteristic scale of the bounce, which translates into a scale of power suppression.

Analytical studies of light bending in a dispersive medium near compact objects, e.g., black holes or neutron stars, are most challenged by a suitable definition of the medium. The most realistic model would be a hot magnetized plasma. In such a medium, however, an analytical description of light rays is very difficult. Therefore, usually an isotropic dispersive medium is assumed in analytical calculations. While it is possible to formulate equations for a general refractive index, which some studies do, most attention in the literature is given to the particular case of a cold, nonmagnetized electron-ion plasma. Whereas this model covers many astrophysically relevant situations, there are indications that in some cases the plasma temperature is so high that the approximation of a cold plasma is no longer valid. For this reason, we consider in this paper a warm, nonmagnetized electron-ion plasma, where the temperature is not set equal to zero but assumed to be small enough, such that relevant equations can be linearized with respect to it. After discussing the general equations for light rays in such a medium on a general-relativistic spacetime, we specify to the axially symmetric and stationary case which includes the spherically symmetric and static case. In particular, we calculate the influence of a warm plasma on the bending angle. In the spherically symmetric and static case, we also calculate the shadow in a warm plasma. We illustrate the general results with a static (respectively corotating) and an infalling warm plasma on Schwarzschild and Kerr spacetimes.

Gravitational waveform templates are a key ingredient for the detection and characterization of gravitational waves emitted by compact binary mergers in the Universe. These templates must be physically accurate and extensive, but also highly computationally efficient, two requirements that are often in tension. One solution to this problem is the development of surrogate models, which are fast, data-driven models trained to predict the output of a slower, physically realistic waveform model. In this article we build on existing work to incorporate machine learning techniques into the conventional reduced order surrogate framework, with a focus on extending coverage to waveform models that describe generically precessing quasicircular binaries. In particular, we present SEOBNRv5PHM_NNSur7dq10, a reduced order neural network surrogate of the SEOBNRv5PHM waveform model, valid up to mass ratios $1:10$ for precessing quasicircular binary black hole systems with arbitrary spin magnitudes and orientations. The faithfulness of the surrogate to SEOBNRv5PHM is validated, and the surrogate is successfully applied to Bayesian parameter inference using both real and injected gravitational wave data. The surrogate is approximately five times faster than SEOBNRv5PHM when evaluating a single waveform on a central processing unit, and nearly 1000 times faster per waveform when amortizing the cost over large waveform batches on a graphics processing unit.

We study static spherically symmetric Kundt solutions to the vacuum field equations of quadratic gravity with a cosmological constant, as well as specific models of six-derivative gravity. In quadratic gravity, we identify all solutions for coupling constants satisfying $\alpha \ne 3\beta$, while the case $\alpha =3\beta$ is studied using the Frobenius method, where we derive the recurrence relations for the power series. In contrast, in six-derivative gravity, we focus on selected models to illustrate the variety of closed-form solutions; we also analyze possible indicial families of Frobenius solutions. For all solutions, we analyze curvature singularities and their accessibility to geodesic observers. We then construct exact gravitational-wave solutions propagating on some of these backgrounds in quadratic and six-derivative gravity. It is known that in Einstein gravity, gravitational waves on the Nariai background unavoidably contain singularities, which are interpreted as physical sources generating these gravitational waves. In contrast, in addition to singular solutions, for appropriate values of the coupling constants, higher-order gravities allow for globally smooth solutions representing gravitational waves.

We formulate an analog transverse first law for general closed marginally trapped surfaces in arbitrary spacetimes. The construction is intrinsically quasilocal and is attached directly to an individual marginally trapped surface, rather than to a preferred horizon worldtube. Taking the Hawking energy as the internal energy and an invariant effective surface gravity associated with the marginally trapped surface as the quantity controlling the thermal term, we derive a balance law in which the variation of energy splits into a generalized heat contribution and a total work contribution. In this way, the resulting law provides a codimension-two, transverse counterpart to existing horizon-based formulations of black-hole thermodynamics. We show that the formalism reproduces the expected results for round spheres in spherically symmetric spacetimes. We then examine semiclassical equilibrium and evaporating regimes and extend the analysis to nonspherically symmetric marginally trapped surfaces in Kerr. These examples indicate that the framework remains applicable in situations where a horizon-based treatment is either nonunique or technically cumbersome, and suggest that closed marginally trapped surfaces provide a natural arena for a genuinely quasilocal thermodynamics of black holes.

We further develop and systematically test a minimally assumption-dependent inversion framework for reconstructing the dark-energy density evolution from type Ia supernova distance-redshift measurements. Instead of adopting a parametric form for the equation of state or employing kernel-based smoothing, we derive an explicit inversion that expresses the normalized dark-energy density, $X(z)\equiv {\rho }_{\mathrm{DE}}(z)/{\rho }_{\mathrm{DE}}(0)$, directly in terms of the redshift derivative of the supernova distance modulus. We apply the method to the $\mathrm{Pantheon}+\text{compilation}$, restricting to $z>0.01$, and estimate the required derivative using a dynamic redshift-binning scheme with approximately equal occupancy per bin. To assess robustness, we compare a local central finite-difference estimator with covariance-based error propagation to an independent Savitzky-Golay local-polynomial reconstruction, finding qualitatively consistent trends, though with estimator-dependent differences in amplitude, for the binnings studied. The reconstructed $X(z)$ is broadly compatible with the $\mathrm{\Lambda }$ cold dark matter expectation $X\simeq 1$ over the low- and intermediate-redshift range, with a moderate enhancement near $z\approx 0.03–0.06$ and a clear, increasingly noisy rise above unity for $z\gtrsim 0.4$. We further show that increasing the number of bins systematically increases both the amplitude and the propagated uncertainty of the reconstructed values, an effect we trace to the quadratic amplification of derivative noise inherent to the inversion [$X(z)\propto D(z{)}^{-2}$]; among the binnings studied, coarser binning yields the more stable reconstruction. Our results demonstrate that direct inversion provides a transparent, data-driven consistency test for dark-energy evolution—including an explicit diagnostic of its own noise-amplification limitations—that can be straightforwardly extended to forthcoming high-precision distance measurements.

When the axion mass is generated during a first-order phase transition and becomes nonvanishing only inside expanding true-vacuum bubbles, the standard picture of misalignment production is qualitatively modified. Using lattice simulations in an expanding universe, we study dark matter production within such a framework and identify two distinct regimes. For rapid transitions, the onset of oscillations is delayed until bubble percolation, enhancing the relic abundance. For slower transitions, spatial gradients generated by expanding bubbles suppress the effective misalignment angle through the bubble misalignment mechanism. We derive a semianalytical expression for the relic density that provides a unified description of both regimes and accurately reproduces the simulation results. Finally, we show how this mechanism also modifies isocurvature perturbations and the small-scale matter power spectrum, with important implications for axion minicluster formation.

Continuous gravitational waves have the potential to transform gravitational wave astronomy and yield fresh insights into astrophysics, nuclear and particle physics, and condensed matter physics. We evaluate their detectability by combining various theoretical and observational arguments from the literature and systematically applying those arguments to known astronomical objects and future gravitational wave detectors. We detail and update previous estimates made in support of Cosmic Explorer [Evans et al., arXiv:2306.13745 and Gupta et al., Classical Quantum Gravity 41, 245001 (2024)]. It is commonly argued that the spins of accreting neutron stars are regulated by gravitational wave emission and that millisecond pulsars contain a young pulsar’s magnetic field buried under accreted material. If either of these arguments holds, the first detection of continuous gravitational waves is likely with near future upgrades of current detectors, and many detections are likely with next generation detectors such as Cosmic Explorer and the Einstein Telescope. A lack of detections in the next several years would begin to raise serious doubts about current theories of millisecond pulsar formation.

For dwarf galaxies modeled as deformed Plummer spheres and orbitally moving in ultralight dark matter halo of the Milky Way, the torque induced by the dynamical friction force is determined and obtained to be much smaller than the torque produced by the gravitational force of the Milky Way. As to the tidal torque, it is found that its magnitude differs significantly for the Plummer and Gaussian density profiles of ultralight dark matter. Possible oscillations of dwarf galaxies caused by the tidal torque and misalignment of dwarf galaxies with respect to their equilibrium position are investigated. It is suggested that more accurate measurements of dwarf-galaxy rotation velocities and improved modeling of dark matter distributions could provide useful constraints on the nature and properties of dark matter.

We construct a quantum information-centered approach to describe the experimentally observed behavior of hyperon spin-pair correlations in high-energy collider experiments. The evolution of the spin density matrix of the hyperon pair is treated in the language of quantum channels, accounting both for the spin dynamics in ${\mathbb{C}}^2\otimes {\mathbb{C}}^2$ and for the pair’s angular separation $\mathrm{\Delta }R$. We show that the experimental data are consistent with an evolution under a two-qubit depolarizing channel, from which a Lindblad master equation is derived. This provides an open quantum system picture of spin dynamics during the hadronization transition, which is not naturally captured by other quantum channels, and we discuss its microscopic origins. These results show that quantum information science can offer new insights into confinement dynamics beyond the classification of entanglement in the final particle states.

In this work, we apply topic modeling to detect new physics in proton-proton collisions at the LHC in an unsupervised way. We investigate three new physics scenarios where fully leptonic $t\overline{t}\to b\overline{b}{\ell }^{+}{\ell }^{-}{\nu }_{\ell }{\overline{\nu }}_{\ell }$ is the main source of background without relying on jet substructure variables. We demonstrate that the algorithm remains effective even in this low-particle multiplicity framework, complementing jet tagging studies, where it is typically employed. Moreover, we demonstrate that the performance of topic modeling is competitive or even better than well-known semisupervised outlier detectors, such as isolation forest and variational autoencoders, and unsupervised algorithms like Gaussian mixture models and k-means clustering with moderate and high-background pollution in almost all new physics scenarios considered.