Real scalar fields, e.g., the axion, cannot condensate into stationary solitonic configurations to form starlike structures, eventually either dispersing or collapsing. However, by relaxing the stationarity condition on the metric, it has been shown that oscillatory solitonic solutions—known as oscillatons—exist. Oscillatons share several properties with boson stars, including comparable compactness and mass ranges. However, their time-dependent nature can lead to potentially discriminating observable signatures. In this work, we explore the observational properties of oscillatons. We find that stable oscillatory circular orbits exist, extending down to the center of the configuration, supporting the possibility of accretion disk structures within the star. We compute the deflection of light rays and verify that it is largely insensitive to the time dependence of the metric. Despite this, the oscillatory behavior of the redshift factor has a strong effect on the observed intensity profiles from accretion disks, producing a breathinglike image whose frequency depends on the mass of the scalar field. In fact, their oscillation period may lie within the observational windows of the Event Horizon Telescope for Sgr ${\mathrm{A}}^{*}$ and $\mathrm{M}{87}^{*}$, suggesting that this “twinkling” behavior may provide a potential observable signature of time-dependent compact objects. A detailed assessment of detectability in realistic interferometric observations is left for future work.

We present a complete characterization of stable, off-equatorial circular orbits around magnetically charged black holes (MBHs). For a static, spherically symmetric MBH, we derive an exact analytic expression for the orbital latitude $\theta$ as a function of radius $r$ and we analyze the effect of synchrotron radiation. We show that charged particles such as electrons and protons can exhibit $\mathcal{O}(1)$ latitude deviations at the innermost stable circular orbit radius and remain stable under synchrotron emission even for extremely small values of the black hole magnetic charge. We then extend the analysis to rotating MBHs, numerically computing the prograde and retrograde orbital branches and demonstrating how frame dragging modifies their structure and stability regions. We show that these off-equatorial orbits are a unique feature of the magnetic charge, being forbidden in the analogous electrically charged Kerr-Newman spacetime. Our results suggest that environments surrounding magnetically charged black holes can exhibit distinctive phenomenological signatures, potentially offering a way to constrain the magnetic charge of astrophysical black holes.

Current and upcoming large-scale structure surveys are pushing toward increasingly wide angular coverage, where wide-angle effects—arising from the varying line of sight across the curved sky—become critical for accurate modeling of the three-dimensional galaxy power spectrum. At the same time, these survey’s broader redshift reach makes the effects of redshift evolution—beyond the effective-redshift approximation—non-negligible on large radial scales. Additional observational effects such as the survey window function and integral constraints also become significant on these large scales, necessitating a careful theoretical treatment to robustly constrain local primordial non-Gaussianities and relativistic effects. In this work, we present a consistent and accurate theoretical framework for modeling the commonly used power spectrum multipoles (PSM) on large scales using the discrete spherical Fourier-Bessel (dSFB) basis. This basis ensures numerical stability and allows an exact separation between angular and radial modes. Using the dSFB basis, we study the impact of wide-angle effects and redshift evolution on the PSM, and incorporate the effects of window function convolution and integral constraints. We validate our PSM modeling using lognormal mocks under radial integral constraints with realistic survey geometries, demonstrating the readiness of our framework for application to all-sky galaxy surveys.

Fuzzy dark matter (FDM) predicts the existence of virialized halos with interference-driven granular structure generated by the wave nature of ultralight bosons. Since these fluctuations produce time-dependent gravitational fields, they can be proposed as a potential source of observable dynamical effects on baryonic matter. In this work we test whether such fluctuations generate measurable temporal correlations between FDM and a coupled gas component. We evolve coupled FDM-gas configurations with the Schrödinger-Poisson-Euler system in three dimensions. The FDM component is initialized through multimerger configurations that relax toward core-halo structures, while the baryonic component is modeled as an ideal gas. After virialization, we analyze the temporal fluctuations of both components through correlation functions and spectral diagnostics. The FDM density field shows fluctuations with significant high-frequency content, whereas the gas develops smoother and longer-lived coherent structures. Although the gas dynamically responds to the gravitational potential generated by the FDM halo, we find no strong temporal correlation between the interference-driven fluctuations of FDM and the gas dynamics. This behavior persists across the explored range of gas temperatures. Our results indicate that baryonic matter reacts to the global gravitational potential of the virialized halo rather than to the detailed phase-dependent granular structure of FDM. This weak temporal coupling may limit the possibility of directly detecting FDM granularity through local baryonic temporal fluctuations.

Bayesian inference, widely used in gravitational wave parameter estimation, depends on the choice of priors, i.e., on our previously existing knowledge. However, to investigate neutron star mergers, priors are often chosen in an agnostic way, leaving valuable information from nuclear physics and independent observations of neutron stars unused. In this work, we propose to encode information on neutron star physics into physics-informed prior distributions constructed with normalizing flows. These priors take input from constraints on the nuclear equation of state and neutron star mass distributions. Applied to GW170817, GW190425, and GW230529, we highlight two contributions of the framework. First, we demonstrate its ability to provide source classification and to enable model selection of equation-of-state constraints for loud signals such as GW170817, directly from the gravitational wave data. Second, we obtain narrower constraints on the source properties through these informed priors. As a result, these physics-informed priors consistently recover higher luminosity distances compared to agnostic priors. Our method provides a scalable way for classifying future ambiguous low-mass mergers observed through gravitational waves and for informing single-event gravitational wave data analysis with neutron star physics.

We derive a steady-state warped-disk equation in the full Kerr spacetime to study the tilt dynamics of a thin, viscous accretion disk around a spinning collapsed object. The formulation, based on Pringle’s framework, remains valid for all values of the Kerr parameter $a$, thereby encompassing both Kerr black holes (BHs, $0<a\le 1$) and Kerr naked singularities ($a>1$). By incorporating the exact Keplerian and Lense-Thirring precession frequencies, we analytically obtain the radial tilt equations of the disk without invoking slow-spin or weak-field approximations. Numerical solutions of the resulting equations obtained under realistic boundary conditions reveal significant deviations from slow-spin approximations, particularly in the inner disk where the relativistic effects dominate. In the diffusive regime, we find that for Kerr naked singularities, the tilt profile exhibits distinct inner hump(s) near the radius where the specific angular momentum vanishes—a feature absent for Kerr BHs. Consideration of a tilt in the inner disk could significantly influence the interpretations from observed X-ray spectral, timing, and polarization features, which are crucial to probe the strong gravity regime and to infer the spin of the central object. While such a distinct hump feature alone does not uniquely distinguish Kerr BHs from Kerr naked singularities, their interpretation, in conjunction with constraints on the disk regime, may provide a potential observational handle on the nature of the accreting collapsed object.

NGC 1275 showed two TeV $\gamma$-ray outbursts between November 2022 and January 2023, as detected by the Large High Altitude Air Shower Observatory. The source was also active in the x-ray and GeV bands during the TeV outburst period. Very-long-baseline radio observations reported a sudden acceleration and deflection of a jet knot in late 2022, before the main TeV activity. Motivated by this sequence, we examine whether magnetic reconnection triggered by the interaction between the jet and the ambient medium can explain the TeV flares. In this picture, reconnection produces many plasmoids, and a large “monster” plasmoid becomes the main flare region. We model the low-state emission with a multizone stochastic-dissipation component and add a compact reconnection-powered region for the flaring state. We then compare leptonic and hadronic interpretations. The leptonic model explains the enhanced x-ray emission as electron synchrotron radiation and the TeV emission mainly as inverse-Compton radiation. A pure proton-proton model can also produce TeV photons if dense target gas is present, but it requires a compact cloud with a density above the values directly inferred from free-free absorption and a large proton power. These requirements are demanding, but they do not by themselves exclude the hadronic interpretation, because the gas may be compressed by the jet or may contain denser cloud cores. Our results show that magnetic reconnection in the parsec-scale jet is a viable origin of the 2022–2023 TeV activity of NGC 1275, while better constraints on the gas density and jet power are needed to distinguish between leptonic and hadronic radiation channels.

It has been suggested that spinning wormholes may mimic Kerr black holes in astronomical sources such as x-ray binaries and supermassive compact objects in centers of galaxies. With recent advances in instrumentation this could be tested if clear differences between the expected wormhole and black hole accretion properties were identified. We find that at a given circumferential radius the physical quantities relating to circular orbits in the equatorial plane are exactly the same for the spinning wormhole and a black hole of the same mass and angular momentum, if only the two spacetime metrics differ in the $g_{rr}$ component alone. A Kerr-like wormhole is a perfect black hole mimicker in relation to the orbital properties in the equatorial plane. The angular velocity, specific energy, specific angular momentum, and Lense-Thirring precession rate are the same for a Kerr black hole and a Kerr-like wormhole in circular orbits of the same circumference. However, for a wormhole there are no orbits of radius less than that of its throat, and this yields an observable signature. We note that the surface area of a disk in the equatorial plane is different in the two spacetimes, and this allows a fairly direct method of measuring the $g_{rr}$ component of the metric when a geometrically thin and optically thick accretion disk is present: the radiative flux is inversely proportional to the square root of $g_{rr}$. This results in a visibly suppressed blackbody disk temperature for traversable wormholes with a sufficiently wide throat, with the temperature decreasing monotonically (relative to the Kerr result) as the throat is approached.

The chiral magnetic effect (CME), arising from the chiral anomaly and enabling a mutual conversion between magnetic topology and fermionic chirality, is a key mechanism in magnetar field evolution. In previous work, Dehman and Pons [Phys. Rev. Res. 7, 033231 (2025).] demonstrated that the CME can efficiently generate dipolar fields ($B_{\mathrm{dip}}\gtrsim {10}^{14}\mathrm{G}$), consistent with magnetar timing measurements, provided that the initial magnetic field carries net helicity. However, whether neutron stars are born with magnetic helicity remains uncertain. In this work, we investigate the CME across a range of initial helicity configurations, including nonhelical initial conditions. We find that the CME efficiently generates magnetar-strength dipoles on timescales of decades, independently of the initial helicity content. The chiral instability is driven by localized helical structures that induce a residual chiral asymmetry and is primarily governed by the maximum chiral chemical potential, requiring ${\mu }_5^{\max }\gtrsim \mathrm{few}\times {10}^{-11}\mathrm{MeV}$ for onset in the magnetar regime. Our results further show that these dipoles may either remain stable and subsequently evolve through standard Ohmic decay, or become unstable if they acquire sufficient helicity, in which case they decay through the chiral anomaly, transferring energy to less helical modes. This outcome depends sensitively on the initial helicity distribution. These findings extend the applicability of the CME to more realistic magnetic-field configurations and underscore the importance of the helicity distribution at birth; a quantity that remains poorly constrained in newborn neutron stars, yet is crucial for determining their magnetic evolution and the emergence of magnetars.

Unidentified falling objects (UFOs) refer to sporadic beam losses observed during LHC operation. The prevailing explanation is that micrometer-sized dust particles released from the beam screen produce beam losses through interactions with the protons. However, the release mechanism of these particles remains unknown. We propose that roughly (1–10)% of UFOs may be caused by axion quark nuggets (AQNs), macroscopic dark matter (DM) candidates with masses of order (5–1000) g. The AQN model naturally relates the dark and visible matter abundances (${\mathrm{\Omega }}_{\mathrm{DM}}\sim {\mathrm{\Omega }}_{\text{visible}}$) and provides a mechanism for generating the baryon-antibaryon asymmetry, with DM composed of both matter and antimatter AQNs. When passing underground within approximately 100 km of the LHC, an antimatter AQN generates acoustic waves strong enough to trigger multiple UFO events within 2 s. If three correlated UFOs (placed at different locations along the LHC ring) are detected, the signal-to-noise ratio can exceed 5 across the entire allowed AQN mass range for a measurement time of about 360 h. Practically, the LHC can serve as a large broadband acoustic detector for AQNs.

Accurate predictions for dark matter-electron scattering in solids require an all-electron treatment together with a faithful description of dielectric screening beyond simple approximations. In particular, local field effects, arising from microscopic inhomogeneities of the electronic response, can significantly modify scattering rates across relevant momentum and energy scales. We present an all-electron framework for computing dark matter-electron scattering rates that incorporates dielectric screening at the random-phase approximation (RPA) level, including local field effects. Using crystalline silicon as a benchmark, we show that local field effects play an important role both at large momentum transfers, spanning multiple Brillouin zones, and at low momentum near the plasmon resonance. We compute electron recoil spectra and projected sensitivities for nonrelativistic halo dark matter and for boosted dark matter or other dark-sector particles, which are sensitive to the impact of local field effects in these high and low momentum regimes, respectively. We further present RPA dielectric functions including local field effects for Ge, GaAs, SiC, and diamond, enabling a systematic comparison across target materials. These developments are implemented in the open source code qcdark2.

First observation of solar neutrinos through coherent elastic neutrino-nucleus scattering by dark matter (DM) direct detection experiments makes the study of the neutrino fog of the most relevance. This irreducible neutrino background depends on the target material as well as other experimental parameters. Recently, the dependence of the neutrino fog on the DM models under consideration has also been remarked on. In this work, we study the case of isospin-violating dark matter (IVDM) models, discussing specific examples of DM models and making a detailed analysis of the implications of IVDM on the neutrino fog. We also explore the conditions under which this background can be mitigated for specific DM models.

Breaking a global or local $U(1{)}_{\mathrm{B}-\mathrm{L}}$ symmetry at high scales simultaneously generates Majorana masses for heavy righthanded neutrinos and produces a network of cosmic strings. The evolution and decay of these strings source a stochastic gravitational-wave background that may be probed by current and future gravitational-wave experiments, while the decays of the resulting massive righthanded neutrinos can generate the baryon asymmetry of the Universe via leptogenesis. We derive analytical bounds for successful leptogenesis with a global and local $U(1{)}_{B-L}$ symmetry, separately finding an absolute lower bound on the lightest righthanded neutrino mass $M_1>1.74\times {10}^8\mathrm{GeV}$ for thermal initial conditions and $M_1>\mathcal{O}({10}^6)\mathrm{GeV}$ for nonthermal initial conditions. Allowing for near-resonant leptogenesis relaxes these bounds to TeV scale in both cases, making it a viable target at collider searches complementing the GW signals. Full flavor effects are included, and crucially, we determine the region where successful leptogenesis can be probed through gravitational-wave observations in upcoming experiments such as LISA and Einstein Telescope. Importantly, we find that flavor effects rescue regions of the parameter space that are ruled out due to current CMB or gravitational-wave measurements.

In this work, we systematically assess the performance of a new method from [H. Shah et al., Phys. Rev. C 113, L012201 (2026)] for locating the QCD critical point using constant-entropy contours by testing it against various effective QCD approaches. We demonstrate that, while the method yields spurious critical points in purely hadronic models (HRG) due to nonparabolic contour behavior at low temperatures ($T\lesssim 120\mathrm{MeV}$), it accurately reproduces the critical point location in frameworks that feature a genuine phase transition and benchmarked against lattice QCD, such as holographic Einstein-Maxwell-dilaton, and functional QCD approaches. Building on our previous determination of constant entropy contours using lattice data, we extend that analysis to construct a complete lattice-based equation of state (EoS) at finite density, which features a critical point at $(T,{\mu }_B)\approx (114,602)\mathrm{MeV}$. By integrating the extrapolated entropy density with respect to temperature, we reconstruct the pressure, baryon density, susceptibility, and speed of sound in the critical region, and analyze the focusing behavior of isentropic trajectories in the vicinity of the critical point.

Within a Bethe-Salpeter model, we investigate the production of possible $D_s{\overline{D}}_s$ $(X_{s\overline{s}})$ and $D\overline{D}$ $(X_{q\overline{q}})$ bound states in $B$ decays. The bound state properties of the two heavy meson systems are studied in the one-boson-exchange kernel, and the resulting normalized Bethe-Salpeter wave functions are used to calculate the branching fractions of $B^{+}\to X_{s\overline{s}}{K}^{+}$ and $B^{+}\to X_{q\overline{q}}{K}^{+}$. We find that bound-state solutions for the $D\overline{D}$ system exist for all three coupling sets considered, whereas the $D_s{\overline{D}}_s$ system supports a bound state solution only in a restricted parameter region. The predicted branching fractions are in the ranges of $1.09\times {10}^{-5}–20.06\times {10}^{-4}$ for the $D_s{\overline{D}}_s$ bound state and $1.56\times {10}^{-6}–4.14\times {10}^{-4}$ for the $D\overline{D}$ bound state. In particular, if $X(3915)$ is interpreted as a predominantly $D_s{\overline{D}}_s$ bound state, its production branching fraction in $B$ decay is found to be $5.79\times {10}^{-4}$.

We investigate the nonlinear response of flow harmonics $v_2$, $v_4$ to initial-state eccentricities ${\epsilon }_2$, ${\epsilon }_4$ within the Gubser-flow framework. By extending the perturbative solutions of Gubser flow, we derive analytic nonlinear response relations connecting the eccentricities ${\epsilon }_2$, ${\epsilon }_4$ to the flow harmonics $v_2$, $v_4$. Our results reproduce the well-known result $v_4/v_2^2\to 1/2$ in large transverse momentum $p_T$ limit. We have also studied the centrality dependence and scaling behavior of these response coefficients. Furthermore, we study the effects of a mismatch between the participant and reaction planes. We find that the conventional nonlinear response coefficients acquire an additional factor determined by the participant-plane angles, which is often approximated as statistical noise driven by event-by-event fluctuations. This factor can modify both the strength and even the sign of the effective nonlinear response coefficient, making it sensitive to the initial configuration of the colliding nuclei. Our study provides new analytical insight into the origin of collective phenomena in relativistic heavy-ion collisions.

A new two-parameter asymptotically flat (AF) toric gravitational instanton is identified as a special case of the Euclidean double Kerr-Newman-Unti-Tamburino solution, by imposing certain symmetry and regularity conditions on its rod structure. These conditions are solved explicitly, except for one which takes the form of a fifth-order polynomial equation. This gravitational instanton has Euler number $\chi =4$ and Hirzebruch signature $\tau =0$, and its global topology is $\mathbb{C}{P}^2\#\overline{\mathbb{C}{P}^2}$ with a circle $S^1$ removed appropriately. It is the third of an infinite sequence of AF toric gravitational instantons that was proved to exist by Li and Sun, the first two being the Kerr and Chen-Teo instantons. It is also the first known example of an AF gravitational instanton that is not Hermitian.

Dipole-radiationlike deviations from general relativity are most prominent during the early inspiral of compact binaries, making space-ground multiband observations a potential probe of such effects. In the same regime, orbital eccentricity can leave a significant imprint on the waveform and is therefore essential for robust dipole-radiation constraints. For the first time we present a multiband Bayesian inference pipeline for stellar-mass binary black holes that simultaneously incorporates eccentricity and a theory-agnostic dipole-radiation correction. We find strong degeneracies among the dipole parameter, chirp mass, and eccentricity, showing that eccentricity can broaden the inferred dipole posterior by opening an additional degeneracy direction. Even so, for a GW231123-like source, one year of TianQin or LISA observation with ground-informed priors from a next-generation detector network can still constrain the dipole parameter to $|b|\lesssim \mathcal{O}({10}^{-7})$ under inference with noisy data. Our results show that multiband binary black hole observations provide a promising and distinct channel for testing theory-agnostic dipole radiation, while also highlighting the need for more complete waveform modeling in future precision tests of gravity.

We have analyzed LIGO-Virgo-KAGRA (LVK) gravitational-wave events that show some evidence of eccentricity from TEOBResumS waveform-model-based parameter estimations and have performed an independent parameter estimation analysis using direct comparison with full numerical-relativity waveforms from our bank of nearly 2000 simulations of binary black holes. We have used the rapid iterative fitting algorithm for Bayesian parameter estimation and found that GW200208_22 favor eccentricities $e_{20}=0.198_{-0.180}^{+0.119}$ upon entering the LVK band at $\sim 20\mathrm{Hz}$ within a 90% confidence interval. Within this event analysis we have employed 42 new targeted full numerical-relativity (NR) simulations and we have thus found a NR waveform with a higher likelihood than identified by model-based analysis, with an estimated eccentricity at 20 Hz, $e_{20}=0.200$, thus reinforcing the eccentric hypothesis of the binary. We have also used our full bank of numerical waveforms without additional targeted waveforms on GW190620 finding that the estimate favors eccentricities at 10 Hz in $e_{10}=0.190_{-0.186}^{+0.046}$. New specifically targeted simulations will be required to narrow these eccentricity ranges.