A direct test of the $CPT$ symmetry is performed for the electromagnetic decays of ortho-positronium using the Jagiellonian positron emission tomograph (J-PET). We present the precise measurement of the $CPT$-sensitive angular correlation entailing the positronium spin and the momenta of its annihilation photons, surpassing previous studies utilizing the same detection system. Positrons originating from a ${}^{22}\mathrm{Na}$ source are emitted from the detector’s center and subsequently form positronium atoms within the spherical chamber covered with porous material. Reconstruction of annihilation locations using the 192-strip J-PET detector makes it possible to determine the positronium emission direction, which defines the quantization axis along which positronium is polarized, without the application of external magnetic fields. The measurements were performed in total for 356 days resulting in an identification of $47.8\times {10}^6$ events with ortho-positronium decays into three photons. The results are consistent with the exactness of $CPT$ symmetry with measured asymmetry amplitude $-0.00029\pm 0.00022$ (stat.) and with statistical error four times smaller than the previous best measurement.

Tidal Love numbers characterize the conservative, static response of compact objects to external tidal fields. Remarkably, these quantities vanish identically for asymptotically flat black holes in four-dimensional general relativity. This behavior has been attributed to hidden symmetries—both geometric and algebraic—governing perturbations in these space-times. Interestingly, a similar vanishing of selected multipolar Love numbers arises in the context of supersonic acoustic flows. These systems share several key features with black holes in general relativity, such as the presence of an effective acoustic horizon and a wave equation describing linear excitations. In this work, we explore a symmetry-based connection between the two frameworks and demonstrate that the ladder symmetries observed in acoustic black holes can be traced to structural properties of the underlying wave equation, mirroring those found in general relativistic black hole space-times.

If dark matter is composed of massive bosons, a Bose-Einstein condensation process must have occurred during the cosmological evolution. Therefore, galactic dark matter may be in a form of a self-gravitating condensate, in the presence of self-interactions. We consider the possibility that the self-interacting potential of the condensate dark matter is of the logarithmic form. In order to describe the condensate dark matter we use the Gross-Pitaevskii equation with a logarithmic nonlinearity, and the Thomas-Fermi approximation. With the use of the hydrodynamic representation of the Gross-Pitaevskii equation we obtain the equation of state of the condensate, which has the form of the ideal gas equation of state, with the pressure proportional to the dark matter density. The basic equation describing the density distribution of the static condensate is derived, and its solution is obtained in the form of a series solution, constructed with the help of the Adomian decomposition method. To test model we consider the properties of the galactic rotation curves in the logarithmic Bose-Einstein condensate dark matter scenario, by using a sample from the Spitzer photomery and accurate rotation curves (SPARC) data. The fit of the theoretical predictions of the rotation curves with the observational data indicates that the logarithmic Bose-Einstein condensate dark matter model gives an acceptable description of the SPARC data, and thus it may be considered as a possible candidate for the in-depth understanding of the dark matter properties.

We present a general-relativistic study of the distribution of proton superconductivity in strongly magnetized neutron stars (NSs), using the xns code to solve the coupled Einstein-Maxwell equations. We investigate equilibrium configurations with both toroidal and poloidal magnetic field geometries and incorporate complex many-body effects through microscopically derived proton pairing gaps. The models employ equations of state (EoSs) obtained from microscopic many-body theory—including realistic two- and three-body nuclear interactions—as well as from relativistic mean-field approaches. We compare superconducting topologies across our collection of EoSs and explore the influences of magnetic field geometry in stellar models parametrized by central density. Our models confirm the absence of $S$-wave superconductivity in the inner core and, importantly, reveal that nonsuperconducting regions exhibit complex three-dimensional geometries: doughnut-shaped for toroidal fields and prolate-shaped for poloidal fields—spatial structures that are inherently absent in one-dimensional analyses. We also compute magnetic deformations and ellipticities for several millisecond pulsars (MSPs), estimating their continuous gravitational wave strain. While these MSPs remain undetectable by current detectors, next-generation instruments such as the Einstein Telescope and Cosmic Explorer may detect their signals, opening an observational window into internal superconductivity and internal magnetic field of NSs, as well as the fundamental microphysics of dense matter.

Upcoming near-infrared facilities (e.g., JWST/NIRCam, ELT/MICADO) will dramatically increase the detectability of Galactic Center Cepheids despite extreme extinction at optical wavelengths. In this work, we study the impact of dark matter (DM) annihilation on Cepheid stars in the inner parsec of the Milky Way. We show that at captured densities $\rho \sim {10}^5\mathrm{GeV}{\mathrm{cm}}^{-3}$, blue loop evolution can be suppressed, preventing the formation of low-mass ($3–6M_{\odot }$) short-period (1–6 days) Cepheids. For even slightly higher DM densities, Cepheids are suppressed across their entire mass range. A dearth of such variables could provide indirect evidence for DM heating. Notably, this effect occurs at lower DM densities than required to impact main-sequence stars. Future surveys will thus offer a novel, complementary probe of DM properties in galactic nuclei.

Wet extreme mass-ratio inspirals (wet EMRIs), which arise from stellar-mass black holes inspiral into supermassive black holes (SMBHs) within the gas-rich environments of active galactic nuclei (AGN), are primary sources of gravitational waves (GWs) for space-borne detectors such as the Laser Interferometer Space Antenna, TianQin, and Taiji. Unlike “dry EMRIs,” which form through gravitational scattering in nuclear star clusters, wet EMRIs are naturally accompanied by interactions with accretion disks, offering rich multi-messenger science opportunities. They are distinct in generating transient electromagnetic (EM) signals, such as quasiperiodic eruptions, which serve as valuable probes of accretion disk physics and SMBH environments. Their GW signals provide an unprecedented precision of the order of $\mathcal{O}({10}^{-4}\sim {10}^{-6})$ in measuring SMBH mass and spin, enabling the calibration of traditional EM techniques and offering insights into jet formation models. Additionally, wet EMRIs serve as bright and dark sirens for cosmology, facilitating percent-level precision measurements of Hubble parameter through AGN host identification or statistical association. These systems hold immense potential for advancing our understanding of black hole dynamics, accretion physics, and cosmology.

In Standard Model (SM) effective field theory, invisible neutron decay arises from $d=12$ operators. Adding new, light particles to the field content of the SM, such as right-handed neutrinos, allows to construct operators for invisible neutron decay at much lower dimensions. Observing invisible neutron decay, if nucleon decays with charged leptons remain absent, would therefore point towards the existence of new neutral degrees of freedom. Here, we discuss four cases: (i) Adding right-handed neutrinos to the SM; (ii) a right-handed neutrino and an axionlike particle; (iii) a right-handed neutrino and a (nearly) massless singlet scalar; and (iv) a right-handed neutrino and a light $Z^{\prime }$. We give the general tree-level decomposition for the resulting $d=(7–9)$ operators for invisible neutron decay. We also briefly discuss LHC searches related to the exotic states found in these UV completions.

A deeper understanding of QCD matter at strong coupling remains challenging due to its nonperturbative nature. To this end, we study a two-flavor holographic hard-wall model to investigate the properties of QCD at finite-density and zero temperature with a nonvanishing quark mass. A dense matter phase is described by a classical solution of the equations of motion in a homogeneous ansatz. We apply holographic renormalization to formulate the holographic dictionary that relates UV boundary data in the bulk with the physical quantities in QCD. We emphasize a role played by an IR boundary action on the hard wall when analyzing the QCD phase structures in this holographic setup. It is found that a baryonic matter phase is manifested in this model with a high baryon number density and a nearly vanishing chiral condensate. We derive the equation of state for the resulting phase and use it to work out the mass-radius relation for neutron stars. We find that the maximum mass of neutron stars can exceed two solar masses for a wide range of free parameters in this model. We also comment on an alternative scenario about the phase structure such that the baryonic matter phase arises at a baryon number chemical potential greater than a critical value.

DESI observations of baryon acoustic oscillations, combined with cosmic microwave background and type-Ia supernova data, suggest that the dark energy equation of state $w_{\mathrm{DE}}$ crosses the phantom divide from $w_{\mathrm{DE}}<-1$ to $w_{\mathrm{DE}}>-1$ at low redshifts. In shift-symmetric Horndeski and generalized Proca theories with luminal gravitational-wave speed and no direct couplings to dark matter, we show that such a phantom-divide crossing is generically difficult without theoretical pathologies. Breaking the shift symmetry in Horndeski theories allows this transition. We construct an explicit model with broken shift symmetry, in which the scalar field has a potential in addition to a Galileon self-interaction and a quadratic kinetic term. This model realizes the desired phantom-divide crossing at low redshifts without introducing ghosts and Laplacian instabilities.

We study the deformed supersymmetric quantum mechanics with a polynomial superpotential with $\hslash$ correction. In the minimal chamber, where all turning points are real and distinct, it was shown that the exact Wentzel–Kramers–Brillouin periods obey the ${\mathbb{Z}}_4$-extended thermodynamic Bethe ansatz (TBA) equations of the undeformed potential. By changing the energy parameter above/below the critical points, the turning points become complex, and the moduli are outside of the minimal chamber. We study the wall crossing of the ${\mathbb{Z}}_4$-extended TBA equations by this change of moduli and show that the ${\mathbb{Z}}_4$ structure is preserved after the wall crossing. In particular, the TBA equations for the cubic superpotential are studied in detail, where there are two chambers (minimal and maximal). At the maximally symmetric point in the maximal chamber, the TBA system becomes the two sets of the $D_3$-type TBA equations, which are regarded as the ${\mathbb{Z}}_4$ extension of the $A_3/{\mathbb{Z}}_2$-type TBA equation.

The Ishibashi-Kawai-Kitazawa-Tsuchiya matrix model, from the holographic perspective, arises at the $p=-1$ end point of the family of dualities relating type II supergravities on near-horizon $\mathrm{D}p$ brane geometries to ($p+1$)-dimensional super Yang-Mills theories with 16 supercharges. In this work, we detail and expand results reported in a recent paper by establishing the holographic dictionary between gauge-invariant operators in the lowest Bogomol’nyi-Prasad-Sommerfield multiplet of the matrix model and the corresponding Kaluza-Klein fluctuations of Euclidean IIB supergravity compactified on the $\mathrm{D}(-1)$ instanton background. The full nonlinear dynamics of these fluctuations can be encoded in a one-dimensional maximal gauged supergravity, which we construct explicitly. We provide its complete Lagrangian, up to second order in fermions, together with the corresponding supersymmetry transformations. We further discuss real forms of the theory for noncompact gauge groups and their embeddings into ten-dimensional supergravities with Lorentzian signature. From the analysis of the one-dimensional Killing spinor equations, we derive different classes of half-supersymmetric solutions, and discuss their uplifts as well as their relations to known solutions.

Quantum contextuality is the notion that certain measurement scenarios do not admit a global description of their statistics and has been implicated as the source of quantum advantage in a number of quantum information protocols. It has been shown that contextuality generalizes the concepts of nonlocal entanglement and magic and is an equivalent notion of nonclassicality to Wigner negativity. In this paper, the protocol of contextuality harvesting is introduced, and it is shown that Unruh-DeWitt models are capable of harvesting quantum contextuality from the vacuum of a massless scalar quantum field. In particular, it is shown that gapless systems can be made to harvest contextuality given a suitable choice of measurements. The harvested contextuality is also seen to behave similarly to harvested magic and can be larger in magnitude for specific parameter regimes. An Unruh-DeWitt qubit-qutrit system is also investigated, where it is shown that certain tradeoffs exist between the harvested contextuality of the qutrit and the harvested entanglement between the systems and that there are regimes where the two resources can both be present. Some of the tools of contextuality, namely the contextual fraction, are also imported and used as general measures for any form of harvested contextuality, including nonlocal entanglement and magic. Additionally, new criteria for genuine harvesting are put forward that also apply to individual systems, revealing new permissible harvesting parameter regimes.

In this work, we investigate the impact of the possibility of a small, subsolar mass compact star, such as the recently reported central compact object of HESS J1731-347, on the equation of state (EOS) of neutron stars. We have used a hybrid approach to the nuclear EOS developed recently where the matter around nuclear saturation density is described by a parametric expansion in terms of nuclear empirical parameters and represented in an agnostic way at higher density using piecewise polytropes. We have incorporated the inputs provided by the latest neutron skin measurement experiments from PREX-II and CREX, simultaneous mass-radius measurements of pulsars PSR $\mathrm{J}0030+0451$ and PSR $\mathrm{J}0740+6620$, and the gravitational wave events GW170817 and GW190425. The main results of the study show the effect of HESS J1731-347 on the nuclear parameters and neutron star observables. Our analysis yields the slope of symmetry energy $L=45.71_{-22.11}^{+38.18}\mathrm{MeV}$, the radius of a $1.4M_{\odot }$ star, $R_{1.4}=12.18_{-0.88}^{+0.71}\mathrm{km}$, and the maximum mass of a static star, $M_{\max }=2.14_{-0.17}^{+0.26}{M}_{\odot }$ within 90% confidence interval, respectively.

For three-dimensional Kerr–de Sitter space-time, we find the singular energy-momentum and spin tensor sources that generate the nontrivial geometry. The energy-momentum tensor is symmetric, conserved and compatible with a spinning massive point particle whose mass and angular velocity we determine. The calculation is based on the analysis of the holonomy for a closed loop around the singularity of the $SO(1,3)$ Chern–Simons gauge field appropriate for gravity in the presence of a positive cosmological constant. This holonomy is related, via the non-Abelian Stokes theorem, to the singular source terms at the center. Our results may be helpful for a better understanding of the algebra of observables of a local observer in the Kerr–de Sitter space-time.

Axion dark matter passing through the magnetospheres of magnetars can undergo hyperefficient resonant mixing with low-energy photons, leading to the production of narrow spectral lines that could be detectable on Earth. Since this is a resonant process triggered by the spatial variation in the photon dispersion relation, the luminosity and spectral properties of the emission are highly sensitive to the charge and current densities permeating the magnetosphere. To date, a majority of the studies investigating this phenomenon have assumed a perfectly dipolar magnetic field structure with a near-field plasma distribution fixed to the minimal charge-separated force-free configuration. While this may be a reasonable treatment for the closed field lines of conventional radio pulsars, the strong magnetic fields around magnetars are believed to host processes that drive strong deviations from this minimal configuration. In this work, we study how realistic magnetar magnetospheres impact the electromagnetic emission produced from axion dark matter. Specifically, we construct charge and current distributions that are consistent with magnetar observations and use these to recompute the prospective sensitivity of radio and submillimeter telescopes to axion dark matter. We demonstrate that the two leading models yield vastly different predictions for the frequency and amplitude of the spectral line, indicating systematic uncertainties in the plasma structure are significant. Finally, we discuss various observational signatures that can be used to differentiate the local plasma loading mechanism of an individual magnetar, which will be necessary if there is hope of using such objects to search for axions.

Motivated by extensive new high-precision experimental data, we present an updated analysis of the two-body charm decays $D\to PV$ (with $P=\pi ,K,{\eta }^{(\prime )}$ and $V=\rho ,K^{*},\omega ,\varphi$) within the factorization-assisted topological-amplitude (FAT) approach. In the framework, flavor SU(3) symmetry breaking effect is incorporated into the topological amplitudes, allowing the nonfactorizable contributions from topological diagrams to be expressed as a minimal set of universal parameters determined through a global fit to experimental data. Thanks to the sufficient data with high precision, we are now able to quantify the nonfactorizable contribution of so-called “factorization” $T$ diagram, which is essential for explaining the observed branching ratios. The parameters for the $C$, $E$, and $A$ diagrams are also updated with significant improved precision, and notably, the resulting strong phases differ substantially from those in the earlier FAT analysis. We find that the $C$ topological amplitude features substantial nonfactorizable effects in the charm sector. These refined parameters enable predictions of significantly improved accuracy, yielding branching ratios in good agreement with current data and the latest results in topological diagram approach, and the predicted direct $CP$ asymmetries differ distinctly form previous FAT results due to updated strong phases. In several modes, the $CP$ asymmetries are predicted to reach $\mathcal{O}({10}^{-3})$, thereby making them promising observables for future high-precision experiments at STCF, BES III, LHCb, and Belle II. Predictions for unobserved decay modes, especially those with branching fractions of order ${10}^{-4}\sim {10}^{-3}$, are also provided for forthcoming experimental tests.

The Standard Model effective field theory (SMEFT) provides a robust framework for probing deviations in the couplings of Standard Model particles from their theoretical predictions. This framework relies on an expansion in higher-dimensional operators, often truncated at dimension-six. In this work, we compute the effective dimension-eight operators generated by integrating out heavy scalar fields at one-loop order in the Green’s basis within two extended scalar sector models: the two Higgs doublet model and the complex triplet scalar model. In this work, we consider loops that consist of heavy field propagators only. We also investigate the impact of heavy scalar fields on the fermion sector, deriving the fermionic effective operators up to dimension-eight for these models, and detail how contributions can be mapped onto nonredundant bases. To assess the importance of higher-order contributions in the SMEFT expansion, we analyze dimension-eight effects for electroweak precision observables at the next frontier of precision lepton machines such as GigaZ.

We theoretically investigate the impact of the anomalous magnetic moment (AMM) of Dirac fermions on the fermionic Casimir effect under magnetic fields. We formulate it as an extension of the well-known Lifshitz formula. From our formula, we find that the AMM increases the fermionic Casimir energy. In particular, when the AMM is large enough, the Casimir energy is significantly enhanced by the gapless behavior of the lowest Landau level. We also quantitatively estimate the Casimir energy from electron, muon, and constituent quark fields under magnetic fields and propose possible phenomena at finite temperature and fermion density.

This work investigates the prospects for performing a time-dependent angular analysis of $B_s^0\to \varphi {\mu }^{+}{\mu }^{-}$ decays at hadron colliders, and introduces new optimized angular observables associated with $B_s^0$-mixing in the decay rate. The time-dependent normalized decay rate and corresponding probability density function is presented both for when the flavor of the $B_s^0$ meson at production is tagged and when it is untagged. The normalized angular terms linked to $B_s^0$-mixing in the tagged (untagged) case are denoted ${\mathcal{Z}}_i$ (${\mathcal{H}}_i$), and their optimized counterparts as $Q_i$ (${\mathcal{M}}_i$). The expected sensitivities of these observables at the end of Run 3, Run 4, and Run 5 of the LHC are determined using pseudoexperiments generated with a decay-time resolution, background level, and signal yield similar to those reported by the LHCb Collaboration. It is found that all observables can be extracted with Run 3 statistics, and that the ${\mathcal{H}}_i$ and ${\mathcal{Z}}_i$ observables have similar sensitivity, despite the former being suppressed by mixing terms. Moreover, the angular observables only accessible via flavor tagging, such as the equivalent of $P_5^{\prime }$ in the $B_s^0$ system, are found to exhibit sensitivities comparable to current measurements in $B^0\to K^{*0}{\mu }^{+}{\mu }^{-}$ decays once Run 5 datasets are available. Fits to the observables to extract the Wilson coefficients show a significant increase in precision when either the observables accessible via time-dependent analysis, or flavor tagging, are included. A marked increase in sensitivity to $CP$-violating short-distance effects is observed for a subset of the new optimized $M_i$ and $Q_i$ observables.