We systematically explore the trimeson states $\overline{B}{\overline{B}}^{*}{\overline{B}}^{*}$ with various isospin-spin configurations in the quark model by solving exactly the six-body Schrödinger equations with the Gaussian expansion method. The configuration ${[[\overline{B}{\overline{B}}^{*}{]}_0^1{\overline{B}}^{*}]}_{\frac{1}{2}}^0$ is not only approximately 10.2 MeV lower than the threshold of its constituent particles but also about 0.2 MeV below that of the compact tetraquark state $[\overline{B}{\overline{B}}^{*}{]}_0^1$ and ${\overline{B}}^{*}$. This configuration manifests a loose two-body bound state composed of $[\overline{B}{\overline{B}}^{*}{]}_0^1$ and ${\overline{B}}^{*}$, with a size of around 4.75 fm. In contrast, the configurations ${[[\overline{B}{\overline{B}}^{*}{]}_1^1{\overline{B}}^{*}]}_{\frac{1}{2}}^0$, ${[\overline{B}[{\overline{B}}^{*}{\overline{B}}^{*}{]}_1^0]}_{\frac{1}{2}}^0$, and ${[[\overline{B}{\overline{B}}^{*}{]}_1^1{\overline{B}}^{*}]}_{\frac{1}{2}}^1$ exhibit binding energies of less than 1 MeV relative to their constituent particles, establishing a loose three-meson bound state. After coupling three configurations with $\frac{1}{2}{0}^{-}$, the trimeson state with $\frac{1}{2}{0}^{-}$ remains a loosely two-body bound state with a binding energy around 1.5 MeV and a huge size of 2.20 fm, in which the configuration ${[[\overline{B}{\overline{B}}^{*}{]}_0^1{\overline{B}}^{*}]}_{\frac{1}{2}}^0$ is dominant, contributing 80% to the overall probability. Among the four bound configurations, the $\sigma$-meson exchange plays a decisive role. The meson pair $[\overline{B}{\overline{B}}^{*}{]}_0^1$, resembling the short-range strong correlated $p-n$ pair in nuclear physics, prevails over other types of meson pairs. The meson pair $[\overline{B}{\overline{B}}^{*}{]}_0^1$ not only contributes to the binding mechanisms but also influences the spatial structures of those stable trimeson configurations.

Vacuum decay and symmetry breaking play an important role in the fundamental structure of the matter and the evolution of the Universe. In this work we study how the purely classical effect of accretion of fundamental fields onto black holes can lead to shells of symmetry restoration in the midst of a symmetry broken phase. We also show how it can catalyze vacuum decay, forming a bubble that expands asymptotically at the speed of light. These effects offer an alternative, purely classical mechanism to quantum tunneling for seeding phase transitions in the Universe.

The holographic Schwinger effect is investigated in systems with $N_f=0$, $N_f=2$, and $N_f=2+1$ using the Einstein-Maxwell-dilaton (EMD) model, incorporating equation of state and baryon number susceptibility information from lattice quantum chromodynamics (QCD). It is found that the critical electric field is smallest for $N_f=0$, indicating that the Schwinger effect is more likely to occur than in systems with $N_f=2$ and $N_f=2+1$. The critical electric field decreases with increasing chemical potential and temperature across all systems. Additionally, potential analysis confirms that the maximum total potential energy increases with the number of flavors, suggesting that existing particles may reduce the probability of particle pair production.

We consider quantum gravity fluctuations in a pair of nearby gravitational wave detectors. Quantum fluctuations of long-wavelength modes of the gravitational field induce coherent fluctuations in the detectors, leading to correlated noise. We determine the variance and covariance in the lengths of the arms of the detectors, and thereby obtain the graviton noise correlation. We find that the correlation depends on the angle between the detector arms as well as their separation distance. Using our result, we propose an experimental setup to detect this noise. The suggested interferometer configuration can be used to distinguish quantum-gravitational noise from both correlated and uncorrelated sources of background noise.

We study the decomposition of the Hilbert space of quantum field theory in ($d+1$)-dimensional de Sitter spacetime into unitary irreducible representations (UIRs) of its isometry group $\mathrm{SO}(1,d+1)$. First, we consider multiparticle states in free theories starting from the tensor product of single-particle UIRs. Second, we study conformal multiplets of a bulk conformal field theory with symmetry group $\mathrm{SO}(2,d+1)$. Our main tools are the Harish-Chandra characters and the numerical diagonalization of the (truncated) quadratic Casimir of $\mathrm{SO}(1,d+1)$. We introduce a continuous density that encodes the spectrum of irreducible representations contained in a reducible one of $\mathrm{SO}(1,d+1)$. Our results are complete for $d=1$ and $d=2$. In higher dimensions, we rederive and extend several results previously known in the literature. Our work provides the foundation for future nonperturbative bootstrap studies of quantum field theory in de Sitter spacetime.

Despite the no-hair theorem, several notable hairy black hole (BH) solutions exist in both general relativity and modified gravity theories. For such hairs to be detectable, they must extend sufficiently beyond the event horizon. This idea has been rigorously formalized by the no-short-hair theorem, which dictates that all existing hairs of a static spherically symmetric BH must extend at least to the innermost light ring. However, the theorem’s applicability to the astrophysically relevant rotating BHs remains elusive as yet. To address this gap, we examine its validity for rotating BHs in the Konoplya-Rezzolla-Zhidenko-Stuchlík and Johannsen classes. Interestingly, for Klein-Gordon separable BHs in these classes that are solutions of nonvacuum general relativity, the no-short-hair property continues to hold. However, unlike in static cases, this result may not apply in a theory-agnostic fashion due to the rotation-induced repulsive effects. Consequently, we identify a minimal set of additional criteria on the metric and matter content needed for such a generalization in other theories. Our study marks an important first step toward establishing general results on the extent of rotating BH hairs, reinforcing their observational detections. Further extension of this novel result for rotating horizonless objects is also discussed.

We consider Weyl-invariant quadratic Einstein-Cartan gravity coupled to a scalar field and study the inflationary behavior of the coupled system of the scalar field and the pseudoscalar associated with the Holst invariant. We find that the model is characterized by effective single-field inflation occurring at small-field values and analyze its predictions which are in comfortable agreement with existing observations for a range of parameter values.

We give a microscopic derivation of the semiclassical entropy of static black holes in 3D Lovelock gravities, which are certain 3D Horndeski theories that were recently discovered from higher-dimensional Lovelock gravities via various methods and admit black hole solutions analogous to higher-dimensional ones. Assuming the ground state is described by the soliton obtained from the black hole solution by performing a double Wick rotation, we reproduce the semiclassical entropy from the Cardy formula without central charges for the asymptotic growth of the number of states. We explain in detail how the mass of the soliton, which is needed in the Cardy formula, can be computed in the minisuperspace formalism.

We study the effective temperature, as a rate of gravitational redshift, of the Hawking modes perceived by a radially free falling observer at an arbitrary location in a Reissner-Nordström-(anti–)de Sitter [RN(A)dS] spacetime. In particular, the behavior of the modes at the inner horizon, and therein the validity of the strong cosmic censorship conjecture under the effective temperature formalism, has been analyzed across the physically permissible parameter space of the RNdS metric. The modes perceived by observers of both positive and negative specific energies have been taken into consideration. Finally, the behavior of the adiabatic control function has been examined over the position space of the observer to determine the regimes where the effective temperature function yields a Planckian spectrum of thermal radiation.

In relativistic physics, angular momentum is paired with a lesser known conserved quantity, the “mass moment,” which appears as the time-space components of the angular momentum tensor. Calculations of mass moment in electromagnetic and gravitational scattering of point particles have led to some puzzling behavior in which the radiated mass moment does not appear to match the corresponding mechanical change. We review the issues and show how the freedoms of time slicing and asymptotic frame may be used to bring all known results into agreement. The key points are to use hyperboloidal time slices and to allow the perturbative and asymptotic frames to differ by an independent Bondi-Metzner-Sachs (BMS) transformation at early and late times. The relevant BMS transformation involves a translation found recently by Riva et al. Building on this work, we conjecture a flux balance law for all orders in the post-Minkowski expansion.

We study the electrically charged massless scalar response to the general Kerr-Newman black hole and obtain the exact (complex) response coefficients, whose real parts are the Love numbers. We find there is a curious discontinuity between the neutral and charged scalar. The Love numbers vanish for the neutral scalar, but are inversely proportional to the electric charge of the scalar in the small charge limit. We also generalize the results into higher dimensions to some extend.

The anisotropy of the redshift space bispectrum depends upon the orientation of the triangles formed by three $\mathit{k}$ modes with respect to the line of sight. For a triangle of fixed size ($k_1$) and shape ($\mu$, $t$), this orientation dependence can be quantified in terms of angular multipoles $B_{\ell }^m(k_1,\mu ,t)$, which contain a wealth of cosmological information. We propose a fast and efficient Fast Fourier Transform (FFT)-based estimator that computes the bispectrum multipole moments $B_{\ell }^m$ of a three-dimensional cosmological field for all possible $\ell$ and $m$ (including $m\ne 0$). The time required by the estimator to compute all multipoles from a gridded data cube of volume $N_g^3$ scales as $\sim \mathcal{O}(N_g^4)$ in contrast to the direct computation technique, which requires time $\sim \mathcal{O}(N_g^6)$. Here, we demonstrate the formalism and validate the estimator using a simulated non-Gaussian field for which the analytical expressions for all the bispectrum multipoles are known. The estimated results are found to be in good agreement with the analytical predictions for all 16 nonzero multipoles (up to $\ell =6$, $m=6$). We expect the $m\ne 0$ bispectrum multipoles to significantly enhance the information available from galaxy redshift surveys and future redshifted 21 cm observations.

We investigate the cosmological dynamics of a homogeneous scalar field nonminimally coupled to torsion gravity, which also interacts with cold dark matter through energy and momentum transfer. The matter and radiation perfect fluids are modeled using the Sorkin-Schutz formalism. We identify scaling regimes of the field during both the radiation and matter eras. Additionally, we discovered a field-dominated scaling attractor; however, it does not exhibit accelerated expansion, making it unsuitable for describing dark energy. Nevertheless, we find two attractor solutions that do exhibit accelerated expansion: one is a quintessencelike fixed point, and the other is a de Sitter fixed point.

We investigate the ionization state of very energetic cosmic ray nuclei in photon fields, such as the cosmic microwave background in extragalactic propagation and the environment surrounding the acceleration site in astrophysical sources. We focus on the process of pair production with electron capture (PPC), where the interaction of a single photon with a nucleus produces an $e^{\pm }$ pair (similar to Bethe-Heitler process) with the subsequent capture of electron by the nucleus. This process effectively reduces the nucleus charge by one unit and counteracts the photoionization process. We show that during cosmological propagation, where the ultrahigh energy cosmic rays interact predominantly with the cosmic microwave background, ionization dominates over PPC for all the cases of practical interest. However, within the source environment and at sufficiently high energies, ionization and PPC processes can reach an equilibrium, leading to a significant fraction of dressed heavy nuclei. This provides a further limitation to the acceleration of high-$Z$ nuclei to very high energies in environments with hot and dense photon fields.

The scintillation efficiency of noble gases for slow ions has been investigated in the context of direct dark matter searches. To estimate nuclear quenching, Lindhard theory is employed. The electronic linear energy transfer, defined as the electronic energy deposited per unit length, is assessed and utilized to determine the initial track structure produced by recoil ions in liquid Ar and Xe. A theoretical model incorporating biexcitonic collision kinetics with diffusion is applied to assess electronic (scintillation) quenching in the liquid phase. In general, Birks’ law replicates the numerical calculations with a high accuracy, when the initial track radius is assumed to be constant. The scintillation efficiency for 0.5–250 keV Ar ions in liquid Ar is determined, considering no applied electric field. Despite the variability in the experimental results, a satisfactory correlation is achieved using a quarter hard-sphere cross section.

In this paper, we study the effects of vorticity on the QCD phase transition using the linear sigma model coupled to quarks. By going beyond the mean-field approximation and incorporating screening effects via ring diagrams, we explore the chiral symmetry restoration in extreme conditions, such as high temperatures, high densities, and large angular velocities. Our analysis reveals how the critical temperature decreases as the angular velocity increases, suggesting that vorticity catalyzes the symmetry restoration. Additionally, we observe a shift in the critical end point (CEP) in the effective QCD phase diagram, where higher angular velocities move the CEP to lower quark chemical potentials and higher temperatures. Moreover, we analyze the baryon number fluctuations through the normalized fourth moment $\kappa {\sigma }^2=c_4/c_2$ as a function of the collision energy in heavy-ion reactions $\sqrt{s_{NN}}$, which serves as a key observable to identify the CEP. Our study reveals that, for high collision energies, $\kappa {\sigma }^2$ remains nearly constant; however, as the system approaches the CEP, the ratio increases sharply, indicating the proximity of the critical region. This rise is influenced by the presence of vorticity, which causes the CEP to shift to higher collision energies. These findings provide insight into the role of vorticity in heavy-ion collisions.

We investigate $CP$ violation in the decay process ${\overline{B}}_s\to VV\to K^{+}{K}^{-}{K}^{+}{K}^{-}$ within the framework of perturbative quantum chromodynamics, where $V$ represents vector mesons $\varphi$, $\rho$, and $\omega$. We analyze the mixing mechanism among $\varphi -{\rho }^0-\omega$ and provide amplitudes for these decay processes. Moreover, we explore $CP$ violation in the four-body decay process of ${\overline{B}}_s^0\to K^{+}{K}^{-}{K}^{+}{K}^{-}$ involving intermediate vector mesons and their mixing. Notably, significant $CP$ violation is observed for specific two-vector meson intermediate states. Additionally, a substantial amount of $CP$ violation arises from vector mixing when the invariant mass of $K^{+}{K}^{-}$ falls within a certain range. This study holds potential implications for future detection by the LHC experiment.

Using an exact holographic duality formula between the inhomogeneous 2D Ising model and 3D quantum gravity, we provide a formula for “real” zeros of the 2D Ising partition function on finite trivalent graphs in terms of the geometry of a 2D triangulation embedded in the three-dimensional Euclidean space. The complex phase of those zeros is given by the dihedral angles of the triangulation, which reflect its extrinsic curvature within the ambient 3D space, while the modulus is given by the angles within the 2D triangles, thus encoding the intrinsic geometry of the triangulation. Our formula cannot cover the whole set of Ising zeros, but we conjecture that a suitable complexification of these “real” zeros would provide a more thorough formula. Nevertheless, in the thermodynamic limit, in the case of flat planar 2D triangulations, our Ising zeros’ formula gives the critical couplings for isoradial graphs, confirming its generality. Finally, the formula naturally extends to graphs with arbitrary valence in terms of the geometry of circle patterns embedded in 3D space. This approach shows an intricate, but precise, new relation between statistical mechanics and quantum geometry.

We investigate a gravitational model based on local Lorentz invariance and general coordinate invariance. The model incorporates classical scale invariance, which forbids dimensionful parameters, and the irreversible vierbein postulate, which enables continuous degenerate limits of the vierbein, both at a specific scale. Through the dynamics of the system, we demonstrate the simultaneous emergence of the Planck mass and a curved spacetime background.

Discrete geometries in hyperbolic space are of longstanding interest in pure mathematics and have come to recent attention in holography, quantum information, and condensed matter physics. Working at a purely geometric level, we describe how any regular tessellation of ($d+1$)-dimensional hyperbolic space naturally admits a $d$-dimensional boundary geometry with self-similar “quasicrystalline” properties. In particular, the boundary geometry is described by a local, invertible, self-similar substitution tiling, that discretizes conformal geometry. We greatly refine an earlier description of these local substitution rules that appear in the 1D/2D example and use the refinement to give the first extension to higher dimensional bulks; including a detailed account for all regular 3D hyperbolic tessellations. We comment on global issues, including the reconstruction of bulk geometries from boundary data, and introduce the notion of a “holographic foliation”: a foliation by a stack of self-similar quasicrystals, where the full geometry of the bulk (and of the foliation itself) is encoded in any single leaf in a local, invertible way. In the $\{3,5,3\}$ tessellation of 3D hyperbolic space by regular icosahedra, we find a 2D boundary quasicrystal admitting points of 5-fold symmetry which is not the Penrose tiling, and record and comment on a related conjecture of William Thurston. We end with a large list of open questions for future analytic and numerical studies.