The critical dynamics of model $H$ with a conserved order parameter coupled to a transverse momentum density which describes the gas-liquid or binary-fluid transitions is investigated within the functional renormalization group approach formulated on the closed time path. According to the dynamic scaling analysis, model $H$ and quantum chromodynamics (QCD) critical end point belong to the same dynamic universality class in the critical region. The higher-order correction of the transport coefficient $\overline{\lambda }$ and shear viscosity $\overline{\eta }$ arising from mode-couplings are obtained by calculating the two-point correlation functions. The flow equation of a dimensionless coupling constant for nondissipative interactions is derived to look for the fixed-point solution of the system. The scaling relation between the critical exponent of the transport coefficient and that of the shear viscosity is estimated. Finally, the dynamic critical exponent $z$ is obtained as a function of the spatial dimension $d$.

In neutrino physics, analyses often depend on large simulated datasets, making it essential for models to generalize effectively to real-world detector data. Contrastive learning, a well-established technique in deep learning, offers a promising solution to this challenge. By applying controlled data augmentations to simulated data, contrastive learning enables the extraction of robust and transferable features. This improves the ability of models trained on simulations to adapt to real experimental data distributions. In this paper, we investigate the application of contrastive learning methods in the context of neutrino physics. Through a combination of empirical evaluations and theoretical insights, we demonstrate how contrastive learning enhances model performance and adaptability. Additionally, we compare it to other domain adaptation techniques, highlighting the unique advantages of contrastive learning for this field.

Unveiling hidden symmetries within Feynman diagrams is crucial for achieving more efficient computations in high-energy physics. In this paper, we study the symmetries underlying the causal loop-tree duality representations through a graph-theoretic analysis. Focusing on the integrand-level representations of $N$-point functions at one loop, we examine their degeneracy and discover that different causal representations are interconnected through specific transformations arising from the symmetries of cut diagrams. Furthermore, the degeneracy is linked to algebraic constraints among the different causal thresholds. Our findings shed new light on the deeper structures of Feynman integrals and pave the way for significantly accelerating their calculation by interrelating different approaches.

After studying properties of the Nariai solution, including its geodesics, in spherical and de Sitter coordinates, two kinds of accelerated motion are investigated in detail: either observers at rest with respect to the coordinates, or observers in radial motion. Next, massless scalar perturbations of Nariai spacetime in absence of sources are worked out, and an explicit example out of the black hole context of analytic self-force calculation is obtained. Last, self-force effects are studied as well, together with some variant of the type of Poynting-Robertson external force, and also building a test electromagnetic field and a test gravitational field in Nariai spacetime geometry.

In the typical data analysis and waveform modeling of the gravitational waves (GWs) signals for binary black holes (BBHs), it is assumed to be isolate sources in the vacuum within the theory of general relativity (GR). However, various kinds of matter may exist around the source or on the path to the detector, and there also exist many different kinds of modified theories of gravity. The effects of these modifications can be characterized within the parametrized post-Einstein (ppE) framework, and the corresponding phase corrections on the waveform at leading post-Newtonian (PN) order are also expressed by the additional parameters for these effects. In this work, we consider the varying-G theory and the dynamical friction of the dark matter spike as an example. Both of these two effects will modify the waveform at $-4\mathrm{PN}$ order, if we choose the suitable power law index for the spike. We choose to use a statistic to characterize the dispersion between the posterior of $\dot{G}$ for different events. For different astronomical models, we find that this statistic can distinguish these two models very effectively. This result indicates that we could use this statistic to distinguish other degenerate effects with the detection of multiple sources.

The topological censorship theorem suggests that higher-dimensional black holes can possess a domain of outer communication (DOC) of nontrivial topology. In this paper, we seek for a black hole coexisting with two bubbles adjacent to the horizon in five-dimensional minimal supergravity, under the assumptions of stationarity and biaxisymmetry. For simplicity, we also assume that the spacetime is symmetric under the exchange of the two axisymmetric Killing vectors. To find the solution, we combine the inverse scattering method and the Harrison transformation, and we present the conditions for the absence of conical, orbifold, and Dirac-Misner string singularities, respectively. As the result, we find that the black hole with topology of $S^3$ or $S^2\times S^1$ can be supported by two bubbles if we admit the conical singularities (deficits).

Decaying dark matter (DDM) affects the evolution of cosmic structure relative to standard cold, collisionless, stable dark matter (CDM). We introduce a new semianalytic model for the effects of two-body DDM on halo structure and subhalo populations. In this scenario, cold parent dark matter particles decay into less massive daughter particles plus dark radiation with a lifetime comparable to the age of the Universe. Our DDM model is implemented in the open-source software galacticus and accounts for heating (due to the velocity kicks imparted on daughter particles) and mass loss (due to the parent-daughter mass splitting). We show that decays flatten and reduce the amplitude of halos’ inner density profiles. These effects make DDM subhalos susceptible to tidal disruption, which we show yields a mass-dependent suppression of the subhalo mass function relative to CDM. Our predictions for DDM density profiles, velocity dispersion profiles, and subhalo populations are consistent with results from isolated and cosmological DDM N-body simulations. Thus, our model enables efficient and accurate exploration of DDM parameter space and will be useful for deriving constraints from upcoming small-scale structure observations.

We investigate the fundamental mode, or $f$-mode, oscillations of anisotropic quark stars within the framework of full general relativity. We consider two different equations of state (EOS), one is the MIT bag model EOS for noninteracting quark matter, and the other is EOS-A, which incorporates interquark interactions. Our study systematically examines the impact of pressure anisotropy on the equilibrium structure, as well as on the frequencies and damping times of $f$-mode oscillations in quark stars. Our results confirm that the $f$-mode frequency scales linearly with the square root of the average density, with anisotropy influencing both the slope and intercept of this relation. This behavior is consistent with our previous findings for neutron stars. The dependence of the $f$-mode frequency on total mass reveals distinct trends based on the relative dominance of tangential and radial pressure. When the tangential pressure exceeds the radial pressure, the frequency increases monotonically with mass, exhibiting rapid growth for massive quark stars. Conversely, when the radial pressure dominates, the frequency also increases with mass; however, in cases where the radial pressure is significantly greater than the tangential pressure, the frequency decreases as mass increases. Additionally, we find that, for low-mass quark stars, stronger tangential pressure leads to an increase in frequency, while beyond a threshold mass, a further increase in tangential pressure results in a decrease in frequency. For the chosen range of anisotropic strengths, the frequency varies between 1.3 and 2.3 kHz for the MIT bag EOS and between 1.8 and 3.4 kHz for EOS-A. Furthermore, we find that the normalized damping time follows a linear trend with compactness, with anisotropic strength affecting both the slope and intercept of this relation. For a fixed stellar mass, an increase in tangential pressure relative to radial pressure reduces the damping time, whereas a decrease in tangential pressure significantly increases it. The damping time ranges from 83 to 900 ms for the MIT bag EOS and from 60 to 761 ms for EOS-A. Finally, we present semiempirical expressions for both the frequency and damping time as functions of mass, radius, and anisotropic strength. The frequency exhibits a cubic polynomial dependence on anisotropy, while the damping time follows a quartic dependence. Our results provide new insights into the role of anisotropy in quark star oscillations and may aid in constraining the equation of state of dense matter through future gravitational wave observations.

We determine parameters of the renormalization group-consistent three-flavor color-superconducting Nambu–Jona-Lasinio (NJL) model that are suited to investigate possible compact-star configurations. Our goal is to provide quark-matter equations of state (EOSs) that can be used for hadron-quark hybrid-star constructions. To that end, we mainly focus on the parameters of the quark-matter model. By varying the vector and diquark coupling constants, we analyze their impact on the EOS, the speed of sound, the maximum diquark gap, and the mass-radius relation. In almost all configurations, a stable color-flavor-locked (CFL) phase appears in the core of the maximum-mass configurations, typically spanning several kilometers in radius. In other cases, the star’s two-flavor color-superconducting (2SC) branch of the EOS becomes unstable before reaching the CFL transition density. At neutron-star densities, the speed of sound squared reaches up to $c_s^2\sim 0.6$ and the CFL gap up to $\mathrm{\Delta }\sim 250\mathrm{MeV}$. We argue that adding a hadronic EOS at lower densities by performing a Maxwell construction does not increase the maximum mass substantially. Thus we use the $2.0M_{\odot }$ constraint to constrain the NJL model parameters that are suited for the construction of hybrid-star EOS. We construct three examples of the hybrid-star model, demonstrating that there is room for different color-superconducting compositions. The hybrid EOSs obtained in this way can have no 2SC matter or different ratios of 2SC and CFL quark matter in the core. We show that early hadron-quark transitions are possible that can modify the tidal deformability at $1.4M_{\odot }$. We find that these EOSs are consistent with the imposed constraints from astrophysics and perturbative QCD. They allow for different hybrid-star scenarios with a hadronic EOS that is soft at low to intermediate densities ($\sim 1–3n_{\mathrm{sat}}$).

Subsolar mass black holes could show up in gravitational wave observations in future and near-solar mass black holes might have been involved in the events GW190425 and GW190814. Since they cannot form from the stellar evolution, their creation requires exotic mechanisms. One such mechanism involves the capture of dark matter particles by stellar objects and their thermalization. When the criterion for the collapse of these dark matter particles is satisfied, a tiny endoparasitic black hole (EBH) forms and then it accretes matter from the host. The EBH may transmute the host into a black hole of nearly the same mass as the host or lesser, depending on the type of accretion. We examine this complex and poorly-explored accretion mechanism, considering the effects of rotation and viscosity but ignoring some other effects, such as those of pressure and magnetic field, as the first step. Using a general framework to assess the effects of rotation and viscosity on accretion, we show that the accretion could be stalled in some white dwarfs, but not in neutron stars. The stalled accretion should cause an opening in the host’s polar regions, the extent of which depends on the mass and spin of the host.

The ultrahigh frequency emission of gravitational waves by binary systems of black holes has recently been investigated in details in the framework of new experimental ideas around resonant cavities. In this article, we consider the case of elliptic trajectories. At fixed masses and frequency, we conclude that the total amount of energy radiated by the system within the bandwidth of the detector can be significantly higher than for circular orbits. However, owing to subtle experimental effects, the signal-to-noise ratio is, overall, a decreasing function of the eccentricity. Limits on the maximum distance at which a merging of black holes can be detected is therefore not improved by considering elliptic trajectories, when compared to the circular case. The article is written as pedagogically as possible so as to be accessible to the nonfamiliar reader and possibly useful beyond the ultrahigh frequency case.

We investigate the effects of the axionlike particle (ALP)-mediated dark matter (DM) model on neutron star properties using the quantum hadrodynamics model (QHD). Using the relativistic mean-field approximation with the QHD-ALP-DM framework, we compute the equation of state (EoS) of neutron stars. Based on our previous study, we find that typical ALP parameter values have no significant effect on the EoS. We then explore various parametrizations of this model by varying the DM Fermi momentum, $q_f$, and DM mass, $m_{\chi }$. Our results show that increasing $q_f$ or $m_{\chi }$ shifts the energy density to higher values while reducing the maximum mass, radius, and tidal deformability of neutron stars. Finally, comparison with observational constraints from gravitational wave events and pulsar measurements indicates that the allowed parameter space for this model is constrained to $q_f<0.05\mathrm{GeV}$ and $m_{\chi }<1000\mathrm{GeV}$. As a result, our study highlights the importance of next-generation gamma-ray observatories, such as the Cherenkov Telescope Array (CTA), in probing the ALP-mediated DM model.

We study the screening mass of the neutral rho-meson in the presence of strong magnetic fields using the Kroll-Lee-Zumino (KLZ) model. The rho-meson self-energy is computed at one-loop order within the lowest Landau level (LLL) approximation, considering the magnetic field as the dominant energy scale. Due to Lorentz symmetry breaking induced by the external field, we decompose the self-energy into three independent tensor structures, which give rise to three distinct modes. Additionally, the four-momentum splits into parallel and perpendicular components, leading to two types of screening masses: the parallel screening mass ($p_0=0$ and $p_{\perp }\to 0$) and the perpendicular screening mass ($p_0=0$ and $p_{\parallel }\to 0$). Our results show that the zero and perpendicular modes exhibit a monotonically increasing behavior with the magnetic field strength, whereas the parallel mode remains essentially constant. These findings provide new insights into the behavior of vector mesons in strongly magnetized media, with implications for QCD under extreme conditions.

In this work, we systematically study $N(1440)$, $N(1535)$, and $\mathrm{\Lambda }(1405)$ in both the quenched three-quark and five-quark frameworks using the Gaussian expansion method within the chiral quark model. Our calculations show that $N(1535)$ can be reproduced as a three-quark state [$N(1P)$], while $N(1440)$ and $\mathrm{\Lambda }(1405)$ cannot be accommodated as the three-quark candidates, [$N(2S)$ and $\mathrm{\Lambda }(1P)$], respectively. In the five-quark framework, we find that the $\mathrm{\Lambda }K$ state for $N(1535)$ cannot form a bound state, while in the $N\overline{K}$ channel there will $\mathrm{\Lambda }(1405)$ form a shallow bound state. Based on the complex-scaling method, we performed complete coupled-channel calculations and obtained six resonance states with energies ranging from 1.8 to 2.2 GeV, in addition to one bound state located around $\mathrm{\Sigma }\pi$ channel. However, neither molecular candidates in $\mathrm{\Lambda }K$ channel for $N(1535)$ nor $N\overline{K}$ for $\mathrm{\Lambda }(1405)$ are included in these states. This is because the strong coupling between $N\overline{K}$ and $\mathrm{\Sigma }\pi$ will make the $N\overline{K}$ unbound, while the weak coupling between $\mathrm{\Lambda }K$ and $\mathrm{\Sigma }K$ cannot help form a stable structure around $\mathrm{\Lambda }K$ threshold. Thus, under the quenched quark model, our results support $N(1535)$ as a three-quark state, while $N(1440)$ is neither a three-quark nor a five-quark state. In addition, we find that although $\mathrm{\Lambda }(1405)$ can be primarily a five-quark state, it requires a mixture of three- and five-quark components for stability. In the future, an exploration on the mixing effects between bare baryons with these relevant two-body hadronic channel components will be carried out to further test our conclusions.

In light of the recent data for ${\overline{B}}_{(s)}\to D_{(s)}^{(*)}P$ and ${\overline{B}}_{(s)}\to D_{(s)}V$ decays, we perform a model-independent phenomenological analysis in the presence of quasielastic rescattering. With the Wilson coefficients including contributions beyond the standard model, the lifetimes of the $B$ meson and $B_d^0-{\overline{B}}_d^0$ mixing are investigated to clarify correlations among the observables. We show that parameter regions for quasielastic rescattering, the size of color-suppressed tree amplitudes, and new physics are constrained due to the lifetime data. As a consequence, it is revealed that this scenario can be tested by the future LHCb measurement of the width difference in $B_d^0-{\overline{B}}_d^0$ mixing and semileptonic $CP$ asymmetry.

Neutrino-nucleus cross section measurements are needed to improve interaction modeling to meet the precision needs of neutrino experiments in efforts to measure oscillation parameters and search for physics beyond the Standard Model. We review the difficulties associated with modeling neutrino-nucleus interactions that lead to a dependence on event generators in oscillation analyses and cross section measurements alike. We then describe data-driven model validation techniques intended to address this model dependence. The method relies on utilizing various goodness-of-fit tests and the correlations between different observables and channels to probe the model for defects in the phase space relevant for the desired analysis. These techniques shed light on relevant mismodeling, allowing it to be detected before it begins to bias the cross section results. We compare more commonly used model validation methods which directly validate the model against alternative ones to these data-driven techniques and show their efficacy with fake data studies. These studies demonstrate that employing data-driven model validation in cross section measurements represents a reliable strategy to produce robust results that will stimulate the desired improvements to interaction modeling.

A study is presented of $B^{+}\to K_{\mathrm{S}}^0{K}^{-}{\pi }^{+}{K}^{+}$ and $B^{+}\to K_{\mathrm{S}}^0{K}^{+}{\pi }^{-}{K}^{+}$ decays based on the analysis of proton-proton collision data collected with the LHCb detector at center-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. The $K_{\mathrm{S}}^{0}K\pi$ invariant-mass distributions of both $B^{+}$ decay modes show, in the $m(K_{\mathrm{S}}^{0}K\pi )<1.85\mathrm{GeV}$ mass region, large activity which is resolved using an amplitude analysis. A simple model, where $J^{PC}$ amplitudes are described by multiple Breit-Wigner functions with appropriate angular distributions, provides a good description of the experimental data. In this approach a complex mixture of $J^{PC}=0^{-+}$, $1^{++}$ and $1^{+-}$ amplitudes is observed that is dominated by $\eta (1405)$, $\eta (1470)$, $\eta (1760)$, $f_1(1285)$, $f_1(1420)$ and $h_1(1405)$ resonances. The $K_{\mathrm{S}}^{0}K\pi$ Dalitz plots are dominated by asymmetric crossing $K^{*}\overline{K}$ bands which are different for the two $B^{+}$ decay modes. This is due to a different interference pattern between the $1^{++}$ and $1^{+-}$ amplitudes in the two channels. Branching fractions are measured for each resonant contribution.

Carrying the insights of conditional probability to the quantum realm is notoriously difficult due to the noncommutative nature of quantum observables. Nevertheless, conditional expectations on von Neumann algebras have played a significant role in the development of quantum information theory, and especially the study of quantum error correction. In quantum gravity, it has been suggested that conditional expectations may be used to implement the holographic map algebraically, with quantum error correction underlying the emergence of spacetime through the generalized entropy formula. However, the requirements for exact error correction are almost certainly too strong for realistic theories of quantum gravity. In this paper, we present a relaxed notion of quantum conditional expectation which implements approximate error correction. We introduce a generalization of Connes’s spatial theory adapted to completely positive maps, and derive a chain rule allowing for the noncommutative factorization of relative modular operators into a marginal and conditional part, constituting a quantum Bayes’s law. This allows for an exact quantification of the information gap occurring in the data processing inequality for arbitrary quantum channels. When applied to algebraic inclusions, this also provides an approach to factorizing the entropy of states into a sum of terms which, in the gravitational context, may be interpreted as a generalized entropy. We illustrate that the emergent area operator is fully noncommutative rather than central, except under the conditions of exact error correction. We provide some comments on how this result may be used to construct a fully algebraic quantum extremal surface prescription and to probe the quantum nature of black holes.

We construct a new class of topological surface defects in Chern-Simons theory with noncompact, non-Abelian gauge groups. These defects are characterized by isotropic subalgebras defined by solutions of the modified classical Yang-Baxter equation, and their fusion realizes a semigroup structure with noninvertible elements. From a Hamiltonian perspective, we calculate this fusion using the composition of Lagrangian correspondences within the Weinstein symplectic category. Applications include boundary terms and conditions in ${\text{AdS}}_3$ gravity and higher-spin theories.

We investigate a geometric approach to determining the complete set of numerators giving rise to finite Feynman integrals. Our approach proceeds graph by graph, and makes use of the Newton polytope associated with the integral’s Symanzik polynomials. It relies on a theorem by Berkesch, Forsgård, and Passare on the convergence of Euler-Mellin integrals, which include Feynman integrals. We conjecture that a necessary, in addition to a sufficient, condition is that all parameter-space monomials lie in the interior of the polytope. We present an algorithm for finding all finite numerators based on this conjecture. In a variety of examples, we find agreement between the results obtained using the geometric approach and a Landau analysis approach developed by Gambuti, Tancredi, and two of the authors.