We study a three-dimensional holographic conformal field theory under the influence of a background electric field on a spacetime containing two black hole horizons. The electric background is fixed such that there is potential difference between the two boundary black holes, inducing a conserved current. By constructing the holographic duals to this setup, which are solutions to the Einstein-Maxwell equations with a negative cosmological constant in four dimensions, we calculate, to a fully nonlinear level, the conductivity of the conformal field theory in this background. Interestingly, we find that the conductivity depends nontrivially on the potential difference. The bulk solutions are flowing geometries containing black hole horizons which are non-Killing and have nonzero expansion. We find a novel property that the past boundary of the future horizon lies deep in the bulk and show this property remains present after small perturbations of the temperature difference of the boundary black holes.

We study an inflation model with a flat scalar potential supported by observations and find that slow-roll inflation can emerge after a quasicyclic phase of the Universe, where it undergoes repeated expansions and contractions for a finite time period. The initial conditions and the positive spatial curvature required for such nontrivial dynamics align with the quantum creation of the Universe. The key ingredients that trigger inflation are dissipative interactions of the inflaton, which are necessary to reheat the Universe after inflation and thus give us an observational handle on preinflationary physics. Our discovery implies that inflation occurs more robustly after the creation.

We study representations of the Poincaré group that have a privileged transformation law along a $p$-dimensional hyperplane, and uncover their associated spinor-helicity variables in $D$ spacetime dimensions. Our novel representations generalize the recently introduced celestial states and transform as conformal primaries of $SO(p,1)$, the symmetry group of the $p$-hyperplane. We will refer to our generalized states as “partially celestial.” Following Wigner’s method, we find the induced representations, including spin degrees of freedom. Defining generalized spinor-helicity variables for every $D$ and $p$, we are able to construct the little group covariant part of partially celestial amplitudes. Finally, we briefly examine the application of the pairwise little group to partially celestial states with mutually nonlocal charges.

The direct detection of gravitational waves (GWs) of frequencies above MHz has recently received considerable attention. In this work, we present a precise study of the reach of a cubic cavity resonator to GWs in the microwave range, using for the first time tools allowing to perform realistic simulations. Concretely, the boundary integral—resonant mode expansion (BI-RME) 3D method, which allows us to obtain not only the detected power but also the detected voltage (magnitude and phase), is used here. After analyzing three cubic cavities for different frequencies and working simultaneously with three different degenerate modes at each cavity, we conclude that the sensitivity of the experiment is strongly dependent on the polarization and incidence angle of the GW. The presented experiment can reach sensitivities up to $1\times {10}^{-19}$ at 100 MHz, $2\times {10}^{-20}$ at 1 GHz, and $6\times {10}^{-19}$ at 10 GHz for optimal angles and polarizations, and where in all cases we assumed an integration time of $\mathrm{\Delta }t=1\mathrm{ms}$. These results provide a strong case for further developing the use of cavities to detect GWs. Moreover, the possibility of analyzing the detected voltage (magnitude and phase) opens a new interferometric detection scheme based on the combination of the detected signals from multiple cavities.

In the framework of black hole perturbation theory, this work investigates the standing wave solutions in Reissner-Nordtsröm (RN) anti–de Sitter (AdS) spacetimes with a naked singularity. These solutions can be viewed as a specific class of quasinormal modes exhibiting distinct characteristics. The imaginary parts of their frequencies are numerically vanishing, allowing them to persist over an extended period. Besides, these modes are predominantly stationary in terms of the evolution of spacetime waveforms. The numerical calculations are carried out employing the finite difference method, and the quasinormal frequencies extracted by the Prony method are shown to be consistent with those obtained using the matrix method. The obtained waveforms and quasinormal frequencies are shown to be drastically different from those of an extreme RN-AdS black hole. As the quasinormal modes are primarily dissipative, the nondissipative standing waves are attributed to the nature that the singularity can neither be a sink nor a source of the gravitational system.

Beyond-$\mathrm{\Lambda }\mathrm{CDM}$ models have been proposed to address various shortcomings of the standard cosmological model, such as the “Hubble tension.” These models often have an impact on the discrepancy in the amplitude of matter clustering, the “${\sigma }_8$ tension.” To explore the interplay between the two tensions, we suggest a simple method to visualize the relation between the two parameters: $H_0$ and ${\sigma }_8$. For a given extension of the $\mathrm{\Lambda }\mathrm{CDM}$ model and dataset, we plot the relation between $H_0$ and ${\sigma }_8$ for different amplitudes of the beyond-$\mathrm{\Lambda }\mathrm{CDM}$ physics. In this work, we use this visualization method to illustrate the trend of selected cosmological models, including nonminimal Higgs-like inflation, early dark energy, a varying effective electron mass, an extra number of relativistic species and modified dark energy models. Although already studied in the literature, some of these models have not been analyzed in view of the two joint tensions. We stress that the method used here could be a useful diagnostic tool to illustrate the behavior of complex cosmological models with many parameters in the context of the $H_0$ and ${\sigma }_8$ tensions.

Some theoretical models for the early Universe predict a spike-type enhancement in the primordial power spectrum on a small scale, which would result in forming early-formed dark matter halos (EFHs). Some recent studies have claimed to have placed limits on such small scales, which, however, involve uncertainties, such as the physics of substructures and the halo-galaxy relations. In this work, we study the cosmic microwave background (CMB) lensing effect, considering the existence of EFHs, and investigate the potential to probe the EFHs and the primordial perturbations on scales smaller than 1 Mpc, complementing these previous studies. We numerically calculate the angular power spectrum of the lensing potential and the lensed CMB anisotropy of temperature, E-mode, and B-mode polarization, including the nonlinear effects of EFHs. We find the possibility that the lensed CMB temperature anisotropy is significantly enhanced on small scales, $\ell >1000$, and could be tested by component decomposition of observed signals through multifrequency observations. Through the calculation with different models of the spiky-type power spectrum, we demonstrate that the accurate measurements of the CMB lensing effect would provide insight into the abundance of EFHs within the limited mass range around ${10}^{11}{M}_{\odot }$ and the primordial power spectrum on the limited scales around $k\sim 1{\mathrm{Mpc}}^{-1}$. In particular, we find that the existence of such EFHs can amplify the lensed anisotropy of CMB B-mode polarization even on large scales, $\ell <100$, as the overall enhancement by $\sim 5\%$ level compared to the standard structure formation model without EFHs. Therefore, future CMB measurements, such as the LiteBIRD satellite, can probe the existence of the EFHs and the spike-type primordial power spectrum through the precise measurement of the large-scale CMB B-mode polarization.

Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the quantum creation of the Universe from nothing such as the tunneling and no-boundary proposals. The simplest one predicts a closed Universe. Motivated by these facts, we investigate the classical dynamics of a closed universe with a plateau-type potential. Depending on the initial inflaton field value, the universe can undergo a variety of events: an immediate big crunch, a bounce or cyclic phase, and inflation. Although the noninflationary solutions may appear irrelevant to our Universe, they can be turned into single or multiple bounces followed by inflation, taking into account the interactions necessary for the reheating of the Universe after inflation. Thus, the dissipative mechanism in our setup explains both the graceful entry to and exit from inflation and gives us an indirect observational handle on the Universe just after creation. We also comment on the implications of these solutions for probabilistic interpretations of the wave function of the Universe.

Tidal resonances in the final seconds of a binary neutron-star inspiral can excite oscillation modes in one or both of the constituents to large amplitudes. Under favorable circumstances, resonant pulsations can overstrain the stellar crust and unleash a torrent of magnetoelastic energy that manifests as a gamma-ray “precursor flare.” We show that for realistic, stratified stars rotating with a spin frequency of $\gtrsim 30\mathrm{Hz}$, the fundamental $g$ mode or its first overtone can also execute a differential rotation in the crust such that a magnetic field of strength $\gtrsim {10}^{13}\mathrm{G}$ is generated via magnetorotational instabilities. This may help to explain observed precursor rates and their luminosities. Premerger magnetic growth would also provide seed magnetic energy for the postmerger remnant.

We describe two fitting schemes that aim to represent the high-density part of realistic equations of state for numerical simulations such as neutron star oscillations. The low-density part of the equation of state is represented by an arbitrary polytropic crust, and we propose a generic procedure to stitch any desired crust to the high-density fit, which is performed to ensure continuity of the internal energy, pressure, and sound speed for barotropic equations of state that describe cold neutron stars in $\beta$ equilibrium. An extension of the fitting schemes to equations of state with an additional compositional argument is proposed. In particular we develop a formalism that ensures the existence of a $\beta$ equilibrium at low densities. An additional feature of this low-density model is that it can be, in principle, applied to any parametrization. The performance of the fits is checked on mass, radius and tidal deformability as well as on the dynamical radial oscillation frequencies. To that end, we use a pseudospectral single neutron star evolution code based on a nonconservative form of the hydrodynamical equations. A comparison to existing parametrizations is proposed, as far as possible, and to published radial frequency values in the literature. The static and dynamic quantities are well reproduced by the fitting schemes. Our results suggest that, even though the radius is very sensitive to the choice of the crust, this choice has little influence on the oscillation frequencies of a neutron star.

We derive the equations of motion of relativistic magnetohydrodynamics, as well as microscopic expressions for all of its transport coefficients, from the Boltzmann equation using the method of moments. In contrast to G. S. Denicol et al. [Phys. Rev. D 98, 076009 (2018).], where a single component gas was considered, we perform our derivation for a locally neutral fluid composed of two massless particle species with opposite charges. We demonstrate that the magnetohydrodynamical equations of motion become dramatically different for this more realistic system. The shear-stress tensor no longer obeys a single differential equation; it breaks into three nondegenerate components with respect to the magnetic field, each evolving according to different dynamical equations. For large magnetic fields, we further show that the solution of this theory displays oscillatory behavior that can no longer be described by an Israel-Stewart-like theory. Finally, we investigate the derived equations in a Bjorken flow scenario.

In the paper, we discuss the possible interpretation of the $J^P=1/2^{-}$ singly charm pentaquark as hadronic molecules. With the effective Lagrangian method, we further analyze the production properties of singly charm pentaquark from decays of $B$ meson, including strong coupling constants and production branching ratios of the charm pentaquark. Our numerical results show that the branching ratio of production of pentaquark from $B$ meson can reach to order of ${10}^{-6}$.

The large top Yukawa coupling results in the top quark contributing significantly to the quantum correction of the Higgs mass term. Traditionally, this effect is canceled by the presence of top partners in symmetry-based models. However, the absence of light top partners poses a challenge to the naturalness of these models. In this paper, we study a model based on composite Higgs with the top Yukawa coupling originating from dimension-six four-fermion operators. The low cutoff scale of the top quark loop required by the naturalness principle can be realized with a light gauge boson $E_{\mu }$ that connects the hyperfermions and top quarks. A scalarless dynamical model with weakly coupled extended $SU(4{)}_{EC}$ gauge group is presented. The model features an $E_{\mu }$ boson and a $Z_E^{\prime }$ boson both at the sub-TeV scale, which lead to a rich phenomenology, especially in the top quark physics.

Direct detection experiments are looking for nuclear recoils from scattering of sub-GeV dark matter (DM) in crystals, and have thresholds as low as $\sim 10\mathrm{eV}$ or DM masses of $\sim 100\mathrm{MeV}$. Future experiments are aiming for even lower thresholds. At such low energies, the free nuclear recoil prescription breaks down, and the relevant final states are phonons in the crystal. Scattering rates into single as well as multiple phonons have already been computed for a harmonic crystal. However, crystals typically exhibit some anharmonicity, which can significantly impact scattering rates in certain kinematic regimes. In this work, we estimate the impact of anharmonic effects on scattering rates for DM in the mass range $\sim 1–10\mathrm{MeV}$, where the details of multiphonon production are most important. Using a simple model of a nucleus in a bound potential, we find that anharmonicity can modify the scattering rates by up to two orders of magnitude for DM masses of $\mathcal{O}(\mathrm{MeV})$. However, such effects are primarily present at high energies where the rates are suppressed, and thus only relevant for very large DM cross sections. We show that anharmonic effects are negligible for masses larger than $\sim 10\mathrm{MeV}$.

We present a procedure leveraging Bayesian deep active learning to rapidly produce highly accurate approximate bounded-from-below conditions for arbitrary renormalizable scalar potentials, in the form of a neural network which may be saved and exported for use in arbitrary parameter space scans. We explore the performance of our procedure on three different scalar potentials with either highly nontrivial or unknown symbolic bounded-from-below conditions (the most general two-Higgs doublet model, the three-Higgs doublet model, and a version of the Georgi-Machacek model without custodial symmetry). We find that we can produce fast and highly accurate binary classifiers for all three potentials. Furthermore, for the potentials for which no known symbolic necessary and sufficient conditions on boundedness-from-below exist, our classifiers substantially outperform some common approximate analytical methods, such as producing tractable sufficient but not necessary conditions or evaluating boundedness-from-below conditions for scenarios in which only a subset of the theory’s fields achieve vacuum expectation values. Our methodology can be readily adapted to any renormalizable scalar field theory. For the community’s use, we have developed a python package, BFBrain, which allows for the rapid implementation of our analysis procedure on user-specified scalar potentials with a high degree of customizability.

We consider the problem of the explicit description of the gauge-invariant subspace of pure lattice gauge theories in the Hamiltonian formulation, where the gauge group is either a compact Lie group or a finite group. The latter case is particularly interesting for quantum simulation. A basis of states where configurations are grouped according to their holonomies is shown to have several advantages over other descriptions. Using this basis, we compute some properties of interest for some non-Abelian finite groups on small lattices, and in particular we examine the question of whether a certain ansatz introduced long ago is a good approximation for the ground state.

In this work, we calculate the magnetic moment and axial charge of the octet hidden-charm molecular pentaquark family in quark model. The Coleman-Glashow sum rule for the magnetic moments of pentaquark family is always fulfilled independently of $SU(3)$ symmetry breaking. In the $8_{2f}$ flavor representation, the magnetic moments of hidden-charm molecular pentaquark states with spin configuration $J^P={\frac{1}{2}}^{-}({\frac{1}{2}}^{+}\otimes 0^{-})$ are all equal to ${\mu }_c=0.38{\mu }_N$. The axial charges of octet hidden-charm molecular pentaquark states are quite small compared to the axial charge of nucleon. The axial charges of the pentaquark states with the spin configuration $J^P={\frac{1}{2}}^{-}({\frac{1}{2}}^{+}\otimes 0^{-})$ in $8_{2f}$ flavor representation are all zero.

Calorimeter shower simulation is a major bottleneck in the Large Hadron Collider computational pipeline. There have been recent efforts to employ deep-generative surrogate models to overcome this challenge. However, many of best-performing models have training and generation times that do not scale well to high-dimensional calorimeter showers. In this work, we introduce supercalo, a flow-based superresolution model, and demonstrate that high-dimensional fine-grained calorimeter showers can be quickly up-sampled from coarse-grained showers. This novel approach presents a way to reduce computational cost, memory requirements, and generation time associated with fast calorimeter simulation models. Additionally, we show that the showers up-sampled by supercalo possess a high degree of variation. This allows a large number of high-dimensional calorimeter showers to be up-sampled from much fewer coarse showers with high fidelity, which results in additional reduction in generation time.