Determining the spectrum of photons emitted by the quark-gluon plasma nonperturbatively remains an open computational challenge. In this paper, we calculate two moments of that spectrum at a tem-perature $T\approx 254\mathrm{MeV}$, employing lattice QCD with two flavors of $\mathcal{O}(a)$-improved Wilson fermions, without facing an inverse problem. Our central value for the difference of these two moments, which is sensitive to photon energies $\omega \gtrsim \pi T$, is lower than, but compatible with that obtained by integrating the leading-order weak-coupling photon spectrum. This study informs the “direct photon puzzle” in heavy-ion collision phenomenology, where it has proved difficult to simultaneously explain the yield and azimuthal anisotropy of photons not originating from final-state hadronic decays.

We investigate the mixing between flavor-singlet light meson and charmonium operators in the S-wave channels, i.e., pseudoscalar and vector channel, at two different pion masses. We measure statistically significant nonzero correlations between operators with different quark content corresponding to off-diagonal entries of a flavor-singlet mixing correlation matrix. By solving a Generalized Eigenvalue Problem (GEVP) we extract the low-lying energy spectrum and compare it with the one obtained by the different types of operators separately. We also calculate the overlaps between the states created by different operators and the energy eigenstates of the theory and find that all types of operators contribute to resolve the states of interest.

Based on a coupled-channel approach, we investigate the structures of four $P_c$ states through compositeness criteria. Toward a more precise description of the states, we have obtained refined fit results of the LHCb data on the $J/\psi p$ invariant mass distribution of the ${\mathrm{\Lambda }}_b^0\to J/\psi p{K}^{-}$ decay. Allowing for the fact that each of the four $P_c$ states couples strongly to a nearby $S$-wave channel, three criteria on the compositeness/elementariness are adopted in this study: the pole-counting rule, the spectral density function, and the Gamow wave function. Compositeness information is extracted from the scattering amplitudes and the pole parameters (pole positions and residues), without any preconceived assumptions on the nature of the $P_c$ states and without any dependence on the model parametrization. Consistently within the framework of all the three methods, it has been found that the $P_c(4312)1/2^{-}$ is mainly composed by $\overline{D}{\mathrm{\Sigma }}_c$, $P_c(4380)3/2^{-}$ by $\overline{D}{\mathrm{\Sigma }}_c^{*}$, while the $P_c(4440)1/2^{-}$ and $P_c(4457)3/2^{-}$ states both turn out as composite states of ${\overline{D}}^{*}{\mathrm{\Sigma }}_c$. The upper limits of the values of their elementariness are estimated to be rather small. This paper provides an additional confirmation of the molecular interpretation for the $P_c$ states in the literature.

In this letter, we investigate the impact of nonspherical effects on the primordial black hole (PBH) mass function, based on the ellipticity-dependent threshold calculated by performing $3+1$ relativistic numerical simulations. We consider an equation of state of radiation $w≔P/\rho =1/3$ and a softer one $w=1/10$ with $P$ and $\rho$ being the pressure and energy density, respectively. We suppose that the curvature perturbations obey Gaussian statistics with a monochromatic power spectrum and examine the most probable ellipsoidal configurations utilizing peak theory. We also suppose the critical scaling law of the PBH mass near the threshold following the known results. The simulations [Phys. Rev. D 112, 083518 (2025).] show that the nonsphericity can easily prevent the system from black hole formation when the initial fluctuation amplitude is near the threshold (critical scaling regime). Nevertheless, we show that the nonspherical effects make the mass function just a few times smaller and are insignificant on the mass function distribution, including the power-law scaling in the small mass region.

The Jackiw-Teitelboim (JT) gravity model, despite its theoretical significance in exploring quantum gravity, has remained largely a toy model due to the absence of a direct physical realization. This work proposes that a one-dimensional three-component fermion chain can serve as a concrete platform for realizing JT gravity. We demonstrate that through bosonization, two components of the fermion chain contribute to the curved spacetime structure, while the third component manifests as the dilaton field—a crucial element of JT gravity. We establish a direct correspondence between the bosonized fields and JT gravity’s structural and dynamical equations, and show that this system exhibits a black hole solution with an event horizon corresponding to a phase transition in the spin degree of freedom. We also discuss the experimental feasibility of simulating this model using ultracold lithium atoms in optical lattices, opening up possibilities for exploring quantum gravity phenomena in a controlled laboratory setting.

This work serves as the generalization of the work [1], where we investigated the quantum field theory in Klein space which has two time directions. We extend studies to the general spacetime ${\mathbb{R}}^{n,d-n}(n,d-n\ge 2)$ in a similar manner; the “length of time” $q$ is regarded as the evolution direction of the system and additional modes beyond the plane wave modes are introduced in the canonical quantization. We show that this novel formulation is consistent with the analytical continuation of the results in Minkowski spacetime.

We present a new data-driven waveform model for spin-aligned, eccentric binary black hole waveforms, constructed using a Fourier analysis network (FAN) architecture. Compared to conventional multilayer perceptron (MLP) architecture, the FAN architecture achieves $2.55\times$ higher accuracy under the same parameter budget and reduces training time by 7%. Its trigonometric activation functions embed Fourier features into the network, mitigating MLPs’ spectral bias and enabling more accurate modeling of oscillatory waveform structures. Our model supports mass ratios $q<8$, eccentricities $e<0.5$, aligned spins $|{\chi }_{1,2}|<0.99$, and relativistic anamaly $\zeta \in [0,2\pi ]$, covering $\{(\ell ,m)=(2,2),(2,1),(3,3),(3,2),(4,4),(4,3)\}$ spin-weighted spherical harmonic modes. For (2,2)-mode, the median mismatch of our model is 1e-3 under advanced Laser Interferometer Gravitational Wave Observatory sensitivity, and the generation speed is $\sim 5\mathrm{ms}$, which is $50\times$ faster than seobnrv5ehm. In the low-mismatch region ($e<0.42$, $q<6.5$, $\zeta \in [0,2\pi ]$, and $|{\chi }_{1,2}|<0.8$), the maximum mismatch for the (2,2) mode is below 1.3%. Compared to existing eccentric surrogate or data-driven waveform models, it achieves broader parameter coverage while maintaining a comparable level of accuracy (mismatch $\sim {10}^{-3}$). These results demonstrate that the proposed FAN-based model offers a reliable and efficient framework for eccentric waveform modeling, with the potential to accelerate gravitational wave data analysis.

We present seobnrv5thm, an accurate and fast gravitational-waveform model for quasicircular, spinning, nonprecessing binary neutron stars (BNSs) within the effective-one-body (EOB) formalism. It builds on the binary–black-hole approximant seobnrv5hm and, compared to its predecessor seobnrv4t, it (i) incorporates recent high-order post-Newtonian results in the inspiral, including higher-order adiabatic tidal contributions, spin-induced multipoles and dynamical tides for spin-aligned neutron stars, (ii) includes the gravitational modes $(\ell ,|m|)=(2,2),(3,3),(2,1),(4,4),(5,5),(3,2)$, and (4,3), (iii) has a time of merger calibrated to BNS numerical-relativity (NR) simulations, (iv) accurately models the premerger (2,2) mode through a novel phenomenological ansatz, and (v) is 100 to 1000 times faster than its predecessor model for BNS systems with total mass $M\ge 2M_{\odot }$. Thus, seobnrv5thm can be used in Bayesian parameter estimation, which we perform for two BNS events observed by the LIGO-Virgo collaboration, GW170817 and GW190425. The model accurately reproduces bam and sacra NR waveforms with errors comparable to or lower than the intrinsic NR uncertainty. We validate the model against the other state-of-the-art BNS waveform models nrtidalv3 and teobresums and find differences only for highly spinning and highly tidally deformable BNSs, where there is no NR coverage and the models employ different spin prescriptions. Our model serves as a foundation for the development of subsequent seobnr waveform models with matter that incorporate further effects, such as spin precession and eccentricity, to be employed for upcoming observing runs of the LIGO-Virgo-KAGRA collaboration and future facilities on the ground.

In cosmic web analysis, complementary to traditional cosmological probes, the extrema (e.g., peaks and voids) two-point correlation functions (2PCFs) are of particular interest for the study of both astrophysical phenomena and cosmological structure formation. However, most previous studies constructed those statistics via N-body simulations without a robust theoretical derivation from first principles. A strong motivation exists for analytically describing the 2PCFs of these local extrema, taking into account the nonlinear gravitational evolution in the late Universe. In this paper, we derive analytical formulas for the power spectra and 2PCFs of two-dimensional (2D) critical points, including peaks (maxima), voids (minima), and saddle points, in mildly non-Gaussian weak gravitational lensing fields. We apply a perturbative bias expansion to model the clustering of 2D critical points. A generalized Gram-Charlier A series expansion is used to describe the probability density functional of the cosmic density field. We successfully derive the power spectrum of weak lensing critical points up to the next-to-next-to-leading order in gravitational perturbation theory, where trispectrum configurations of the weak lensing field have to be included. We numerically evaluate those power spectra up to the next-to-leading order, which corresponds to the inclusion of bispectrum configurations, and transform them to the corresponding 2PCFs. An exact Monte Carlo integration is performed assuming a Gaussian distributed density field to validate our theoretical predictions. Overall, we find similar properties in two dimensions compared to the clustering of three-dimensional critical points previously measured from N-body simulations. Contrary to standard lensing power spectra analysis, we find distinct baryon acoustic oscillation features in the lensing peak 2PCFs due to the gradient and curvature constraints, and we quantify that non-Gaussianity makes for $\sim 10\%$ of the signal at quasilinear scales, which could be important for current stage-IV surveys.

We perform $3+1$ relativistic numerical simulations to study primordial black hole (PBH) formation from the collapse of adiabatic superhorizon nonspherical perturbations generated from curvature fluctuations obeying random Gaussian statistics with a monochromatic power spectrum. The matter field is assumed to be a perfect fluid of an equation of state $w≔P/\rho =\mathrm{const}.$ with $P$ and $\rho$ being the pressure and the energy density, respectively. The initial spatial profile of the curvature perturbation is modeled with the amplitude $\mu$ and nonspherical parameters $e$ (ellipticity) and $p$ (prolateness) according to peak theory. We focus on the dynamics and the threshold for PBH formation in terms of the nonspherical parameters $e$ and $p$. We find that the critical values ($e_c$, $p_c$) with a fixed value of $\mu$ closely follow a superellipse curve. With $p=0$, for the range of amplitudes considered, we find that the critical ellipticity for nonspherical collapse follows a decaying power law as a function of $(\mu -{\mu }_{\mathrm{c},\mathrm{sp}})$ with ${\mu }_{\mathrm{c},\mathrm{sp}}$ being the threshold for the spherical case. Our results also indicate that, for both cases of $w=1/3$ and $w=1/10$, small deviations from sphericity can avoid collapsing to a black hole when the amplitude is near its critical threshold. Finally we discuss the significance of the ellipticity on the rate of the PBH production.

We introduce a technique to enhance the reliability of gravitational wave parameter estimation results produced by machine learning. We develop two independent machine learning models based on the Vision Transformer to estimate effective spin and chirp mass from spectrograms of gravitational wave signals from binary black hole mergers. To enhance the reliability of these models, we utilize attention maps to visualize the areas our models focus on when making predictions. This approach enables us to demonstrate that both models perform parameter estimation based on physically meaningful information. Furthermore, by leveraging these attention maps, we demonstrate a method to quantify the impact of glitches on parameter estimation. We show that as the models focus more on glitches, the parameter estimation results become more strongly biased. This suggests that attention maps could potentially be used to distinguish between cases where the results produced by the machine learning model are reliable and cases where they are not.

The search for dark matter is one of the crucial open problems in both particle physics and cosmology. If dark matter scatters with Standard Model particles, it could accumulate inside the Earth and begin to annihilate, producing heat within the Earth’s core. While past work has been done on the effect that this heat would have once it reached the surface, we model the flow of heat through the Earth’s core by numerically solving the heat equation to model dark matter’s effect on the interior of the planet. We compute how long it takes for the core to come into thermal equilibrium and show that for a wide range of dark matter parameters, a substantial fraction of the inner core would be melted by dark matter annihilation. Our analysis produces new limits on dark matter annihilating in the Earth, points out important new effects that must be considered when studying planetary heating by dark matter, and suggests new dark matter observables that could be searched for in exoplanet populations.

The electron quantum dynamics at crossing the black hole horizon is investigated. Exploiting the equivalence principle, we show a way to emulate the electron’s dynamics via an appropriately chirped free electron wave packet, where the dynamical characteristics is encoded in the interference fringes of the wave packet. Apart from creating an analog of the gravitational effect, we deduce the electron’s explicit wave function at the horizon of a black hole and provide quantitative predictions on the quantum properties of the electron crossing the horizon. These findings potentially pave the way for a new research avenue in laboratory cosmology based on the use of specially designed free electron wave packets.

The basic framework of the superfluid vortex model for pulsar glitches, though, is well accepted; there is a lack of consensus on the possible trigger mechanism responsible for the simultaneous release of a large number ($\sim {10}^{13}$) of superfluid vortices from the inner crust. Here, we propose a simple trigger mechanism to explain such catastrophic events of vortex unpinning. We treat a superfluid vortex line as a classical massive straight string with well-defined string tension stretching along the rotation axis of pulsars. The crustquake-induced lattice vibration of the inner crust can act as a driving force for the transverse oscillation of the string. Such forced oscillation near resonance causes the bending of the vortex lines, disturbing their equilibrium configuration and resulting in the unpinning of vortices. We consider unpinning from the inner crust’s so-called strong (nuclear) pinning region, where the vortices are likely pinned to the nuclear sites. We also comment on vortex unpinning from the interstitial pinning region of the inner crust. We sense that unifying crustquake with the superfluid vortex model can naturally explain the cause of large-scale vortex unpinning and generation of large-size pulsar glitches.

We construct a non-Abelian spin-1 gauge theory with a cubic interaction in ${\mathrm{AdS}}_4$ from the exact renormalization group (ERG) flow of a conformal field theory (CFT) in three dimensions. The latter is the $USp(2N)$ singlet sector of the free field theory of $2N$ massless complex scalars. The quadratic and cubic terms in the bulk action are those of a gauge fixed version of a (local) gauge invariant action. By construction, this bulk action is the evolution operator for the ERG equation of the boundary theory and thus is guaranteed to reproduce the correct boundary correlators using the usual AdS/CFT prescription. This work expands on the program initiated by one of the authors [A holographic form for Wilson’s RG, Nucl. Phys. B924, 603 (2017)].

We calculate the hard-scattering amplitude of bosonic states created by ${\mathcal{O}}_k^{(8)}$ operators and fermionic states created by ${\mathcal{O}}_{k^{\prime }}^{(6)}$ operators of $\mathcal{N}=4$ SYM theory from the dilaton-dilatino closed-string scattering amplitude in type IIB superstring theory, in the framework of the gauge/string theory duality considering a hard-wall model. These are single-trace operators of the $SU(N_c)$ $\mathcal{N}=4$ SYM theory in four dimensions. We investigate the high-energy scaling at fixed angle and also in the Regge limit. We derive the leading and subleading terms contributing to the scattering cross section. This dual calculation of the hard-scattering amplitude is particularly interesting since it involves the scattering of two different types of external states. We calculate explicitly some angular integrals for two scalar spherical harmonics and two spinor spherical harmonics on the five-sphere, leading to selection rules.

We consider a scalar field coupled to massless fermions through Yukawa couplings, such as the Higgs field, in a Robertson-Walker spacetime. We compute the nonlocal quantum effective action as a functional of the background scalar field and the scale factor at one loop order by integrating the Weyl anomaly resulting from the fermions in the loop. We show that the mode expansion of the scalar field is modified by the quantum nonlocality and the power spectrum of scalar perturbations exiting the horizon exhibits a slow roll with a red tilt proportional to the square of the Yukawa coupling even though the classical spacetime is exactly de Sitter. We comment on possible implications for cosmology.

Two harmonic oscillators interacting through the exchange of a quantum field leads to nonzero entanglement between the two, which is absent for classical interaction. In this work, we determine the entanglement between two such harmonic oscillators living in an expanding universe. It turns out that, if the oscillators are within the Hubble horizon, with their frequencies comparable to the rate of expansion of the Universe, the entanglement is nonzero and significant while, for oscillators outside the Hubble horizon, with oscillation frequencies much higher than the expansion rate, the entanglement is negligibly small.