Realistic black holes are usually dynamical, noticeable, or sluggish. The Vaidya metric is a significant and tractable model for simulating a dynamical black hole. In this study, we consider scalar perturbations in a dynamical Vaidya black hole and explore the quasinormal modes by employing the matrix method. We find the proper boundary conditions of the quasinormal modes from physical analysis in the background of a dynamical black hole for the first time. The results show that the eigenfrequencies become different at the apparent horizon and null infinity, because the physical interactions propagate with finite velocity in nature. Any variation of the hole does not affect the boundary condition at null infinity in a finite time. The quasinormal modes originated around the horizon would not immediately come down to, but slowly go to the final state following the mass accretion process of the hole. The precision of the matrix method is quite compelling, which reveals more details of the eigenfrequencies of the quasinormal mode of perturbations in the Vaidya spacetime.

Ultralight bosons as dark matter has become a model of major interest in cosmology, due to the possible imprint of a distinct signature in the cosmic structure both at the linear and nonlinear scales. In this work we show that the equations of motion for density perturbations for this kind of models can be written in terms of a modified gravitational potential. Taking advantage of this parallelism, we use the mg-picola code originally developed for modified gravity models to evolve the density field of axion models with and without self-interaction. Our results indicate that the quantum potential adds extra suppression of power at the nonlinear level, and it is even capable of smoothing any bumpy features initially present in the mass power spectrum.

We show that the $H_0$ tension can be resolved by making recombination occur earlier, keeping the fit to cosmic microwave background (CMB) data almost intact. We provide a suite of general necessary conditions to give a good fit to CMB data while realizing a high value of $H_0$ suggested by local measurements. As a concrete example for a successful scenario with early recombination, we demonstrate that a model with a time-varying $m_e$ can indeed satisfy all of the conditions. We further show that such a model can also be well fitted to low-$z$ distance measurements of baryon acoustic oscillations (BAO) and type Ia supernovae (SNeIa) with a simple extension of the model. A time-varying $m_e$ in the framework of ${\mathrm{\Omega }}_k\mathrm{\Lambda }\mathrm{CDM}$ is found to be a sufficient and excellent example of a solution to the $H_0$ tension, yielding $H_0={72.3}_{-2.8}^{+2.7}\mathrm{km}/\sec /\mathrm{Mpc}$ from the combination of CMB, BAO, and SNeIa data even without incorporating any direct local $H_0$ measurements. Employing the Bayesian posterior predictive distribution, we find that this model can reduce the $H_0$ tension in the reference $\mathrm{\Lambda }\mathrm{CDM}$ model from $4.8\sigma$ down to $2.2\sigma$. Apart from the $H_0$ tension, this model is also favored from the viewpoint of the CMB lensing anomaly.

Luminosity distance estimates from electromagnetic and gravitational wave sources are generally different in models of dynamical dark energy and gravity beyond the standard cosmological scenario. We show that this leaves a unique imprint on the angular power-spectrum of fluctuations of the luminosity distance of gravitational-wave observations which tracks inhomogeneities in the dark energy field. Exploiting the synergy in supernovae and gravitational wave distance measurements, we build a joint estimator that directly probes dark energy fluctuations, providing a conclusive evidence for their existence in case of detection. Moreover, such measurement would also allow to probe the running of the Planck mass. We discuss experimental requirements to detect these signals.

The application of holographic principle in very early time is studied. The consideration of the principle in the late-time evolution will be a good motivation to study its role at the time of inflation. Since the length scale is expected to be small during inflation, the resulted energy density form the holographic principle is expected to be large enough to drive inflation. The entropy of the system is the main part of the holographic principle, in which modifying entropy will lead to a modified energy density. Here, instead of the original entropy, we are going to apply a modified entropy, known as Tsallis entropy which includes quantum corrections. The length scale is assumed to be GO length scale. Finding an analytical solution for the model, the slow-roll parameters, scalar spectral index, and tensor-to-scalar ratio are calculated. Comparing the result, with Planck $r-n_s$ diagram, we could find a parametric space for the constants of the model. Then, a correspondence between the holographic dark energy and the scalar field is constructed, and the outcome potentials are investigated. In the final part of the work, we have considered the recently proposed trans-Planckian censorship conjecture for the model.

We present a novel calculation of the spectrum of electrons and positrons from random sources, supernova remnants and pulsars, distributed within the spiral arms of the Galaxy. The pulsar emissivity in terms of electron-positron pairs is considered as time dependent, following the magnetic dipole spin-down luminosity, and the temporal evolution of the potential drop is accounted for. Moreover each pulsar, with the magnetic field and initial spin period selected at random from the observed distribution, is considered as a source of pairs only after it leaves the parent supernova due to its birth kick velocity (also selected at random from the observed distribution). We show that (i) the spectrum of electrons is characterized by a feature at $\gtrsim 50\mathrm{GeV}$ that proves that their transport is dominated by radiative losses. The flux reduction at $E\gtrsim 1\mathrm{TeV}$ is explained as a result of lepton transport from sources in the spiral arms. (ii) The spectrum of positrons is very well described by the contribution of pulsars and the rising positron fraction originates naturally. The implications of pulsars as positron sources in terms of positron fraction at very high energies are also discussed. (iii) The role of fluctuations in the high-energy regime is thoroughly discussed and used to draw conclusions on the possibility to single out the contribution of local sources to the lepton spectrum with current and upcoming experiments.

Based on the generalized quantum electrodynamics expression for the Podolsky propagator, which preserves gauge invariance for massive photons, we propose a model for the massive gluon propagator that reproduces well-known features of established strong-interaction models in the framework of the Dyson-Schwinger equation. By adjusting the Podolsky mass and the coupling strength we thus construct a model with simple analytical properties known from perturbative theory, yet well suited to describe a confining interaction. We obtain solutions of the Dyson-Schwinger equation for the quark at spacelike momenta on the real axis as well as on the complex plane and solving the bound-state problem with the Bethe-Salpeter equation yields masses and weak decay constants of the $\pi$, $K$ and ${\eta }_c$ in excellent agreement with experimental values, while the $D$ and $D_s$ are reasonably well described. The analytical simplicity of this effective interaction has the potential to be useful for phenomenological applications and may facilitate calculations in Minkowski space.

In $R$-parity-violating supersymmetry the lightest neutralino can be very light, even massless. For masses in the range $500\mathrm{MeV}\lesssim m_{{\tilde{\chi }}_1^0}\lesssim 4.5\mathrm{GeV}$ the neutralino can be produced in hadron collisions from rare meson decays via an $R$-parity-violating coupling, and subsequently decay to a lighter meson and a charged lepton. Due to the small neutralino mass and for small $R$-parity-violating coupling the lightest neutralino is long lived, leading to displaced vertices at fixed-target and collider experiments. In this work, we study such signatures at the proposed experiments ANUBIS and MoEDAL-MAPP at the LHC. We also compare their sensitivity reach in these scenarios with that of other present and proposed experiments at the LHC such as ATLAS, CODEX-b, and MATHUSLA. We find that ANUBIS and MAPP can show complementary or superior sensitivity.

We study the dynamics of the electroweak phase transition in a simple extension of the Standard Model where the Higgs sector is extended by adding an $SU(2{)}_L$ triplet with hypercharge $Y=2$. By making random scans over the parameters of the model, we show that there are regions consistent with constraints from collider experiments and the requirement for a strong first-order electroweak phase transition which is needed for electroweak baryogenesis. Further, we also study the power spectrum of the gravitational waves that can be generated due to the first-order phase transitions. Moreover, the detectability of these gravitational waves, via future space-based detectors, is discussed.

In this paper we study the axial anomaly in very special relativity electrodynamics using Pauli-Villars and dimensional regularization of ultraviolet divergences and Mandelstam-Leibbrandt regularization of infrared divergences. We compute the anomaly in 2 and 4 dimensional space-time. We find that this procedure preserves the vector Ward identity(charge conservation) and reproduce the standard axial anomaly in 2 and 4 dimensions without corrections from VSR. Finally, we show how to obtain the anomaly in the path integral approach.

We build rigorously the attractive five-dimensional model where bulk fermions propagate along the ${\mathcal{S}}^1/{\mathbb{Z}}_2$ orbifold and interact with a Higgs boson localized at a fixed point of the extra dimension. The analytical calculation of the fermion mass spectrum and effective Yukawa couplings is shown to require the introduction of either essential boundary conditions (EBC) imposed by the model definition or certain bilinear brane terms (BBT) in the action, instead of the usual brane-Higgs regularizations. The obtained fermion profiles along the extra dimension turn out to undergo some discontinuities, in particular at the Higgs brane, which can be mathematically consistent if the action is well written with improper integrals. We also show that the ${\mathbb{Z}}_2$ parity transformations in the bulk do not affect the fermion chiralities, masses and couplings, in contrast with the EBC and the BBT, but when extended to the fixed points, they can generate the chiral nature of the theory and even select the Standard Model chirality setup while fixing as well the fermion masses and couplings. Thanks to the strict analysis developed, the duality with the interval model is scrutinized.

In this work we investigate the usefulness of nuSTORM as a probe of two new-physics scenarios that are sterile neutrinos and nonunitarity of the neutrino mixing matrix. For the sterile neutrino we show the importance of the neutral current events when combined with the charged current events to constrain the effective mixing angle, ${\theta }_{\mu \mu }$, and the sterile mixing angles ${\theta }_{14}$ and ${\theta }_{24}$. We also study the role nuSTORM will play in the study of neutrino oscillation physics if the three generation neutrino mixing matrix is nonunitary. In this context we elucidate the role of nuSTORM, considering both charged current and neutral current events, in constraining the various nonunitarity parameters such as ${\alpha }_{11}$, $|{\alpha }_{21}|$, and ${\alpha }_{22}$.

We present the first calculation within lattice QCD of excited light meson resonances with $J^{PC}=1^{--}$, $2^{--}$ and $3^{--}$. Working with an exact SU(3) flavor symmetry, for the singlet representation of pseudoscalar-vector scattering, we find two $1^{--}$ resonances, a lighter broad state and a heavier narrow state, a broad $2^{--}$ resonance decaying in both $P$- and $F$-waves, and a narrow $3^{--}$ state. We present connections to experimental ${\omega }_J^{\star },{\varphi }_J^{\star }$ resonances decaying into $\pi \rho$, $K{\overline{K}}^{*}$, $\eta \omega$ and other final states.

Recently, the LHCb Collaboration reported a new structure $P_{cs}(4459)$ with a mass of 19 MeV below the ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ threshold. It may be a candidate of molecular state from the ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ interaction. In the current work, we perform a coupled-channel study of the ${\mathrm{\Xi }}_c^{*}{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{\prime }{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{*}\overline{D}$, ${\mathrm{\Xi }}_c{\overline{D}}^{*}$, ${\mathrm{\Xi }}_c^{\prime }\overline{D}$, and ${\mathrm{\Xi }}_c\overline{D}$ interactions in the quasipotential Bethe-Salpeter equation approach. With the help of the heavy quark chiral effective Lagrangian, the potential is constructed by light meson exchanges. Two ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ molecular states are produced with spin parities $J^P=1/2^{-}$ and $3/2^{-}$. The lower state with $3/2^{-}$ can be related to the observed $P_{cs}(4450)$ while two-peak structure cannot be excluded. Within the same model, other strange hidden-charm pentaquarks are also predicted. Two states with spin parities $1/2^{-}$ and a state with $3/2^{-}$ are predicted near the ${\mathrm{\Xi }}_c^{\prime }\overline{D}$, ${\mathrm{\Xi }}_c\overline{D}$, and ${\mathrm{\Xi }}_c^{*}\overline{D}$ thresholds, respectively. As two states near ${\mathrm{\Xi }}_c{\overline{D}}^{*}$ threshold, two states are produced with $1/2^{-}$ and $3/2^{-}$ near the ${\mathrm{\Xi }}_c^{\prime }{\overline{D}}^{*}$ threshold. The couplings of the molecular states to the considered channels are also discussed. The experimental research of those states are helpful to understand the origin and internal structure of the $P_{cs}$ and $P_c$ states.

Electromagnetic dipole moments of short-lived particles are sensitive to physics within and beyond the Standard Model of particle physics but have not been accessible experimentally to date. To perform such measurements it has been proposed to exploit the spin precession of channeled particles in bent crystals at the LHC. Progress that enables the first measurement of charm baryon dipole moments is reported. In particular, the design and characterization on beam of silicon and germanium bent crystal prototypes, the optimization of the experimental setup, and advanced analysis techniques are discussed. Sensitivity studies show that first measurements of ${\mathrm{\Lambda }}_c^{+}$ and ${\mathrm{\Xi }}_c^{+}$ baryon dipole moments can be performed in two years of data taking with an experimental setup positioned upstream of the LHCb detector.

We study particle dynamics in a space-time invariant under the $DISI{M}_b(2)$ group—the deformation of the $ISIM(2)$ symmetry group of very special relativity. We find that the Lorentz violation leads to the creation of higher order (hidden) symmetries, which are connected to those broken at the space-time level. Through the perspective of the conserved quantities of the special relativistic case, the Lorentz violation is linked to specific noncommutative relations in phase space.

We present the first proof-of-principle Cauchy evolutions of asymptotically global anti–de Sitter (AdS) spacetimes with no imposed symmetries, employing a numerical scheme based on the generalized harmonic form of the Einstein equations. In this scheme, the main difficulty in removing all symmetry assumptions can be phrased in terms of finding a set of generalized harmonic source functions that are consistent with AdS boundary conditions. In four spacetime dimensions, we detail an explicit set of source functions that achieves evolution in full generality. A similar prescription should also lead to stable evolution in higher spacetime dimensions, in various couplings with matter fields, and on the Poincaré patch. We apply this scheme to obtain the first long-time stable $3+1$ simulations of four-dimensional spacetimes with a negative cosmological constant, using initial data sourced by a massless scalar field. We present preliminary results of gravitational collapse with no symmetry assumptions, and the subsequent quasinormal mode ringdown to a static black hole in the bulk, which corresponds to evolution toward a homogeneous state on the boundary.

In this paper, we derive the universal (cutoff-independent) part of the holographic entanglement entropy in the noncommutative Yang-Mills theory and examine its properties in detail. The behavior of the holographic entanglement entropy as a function of a scale of the system changes drastically between large noncommutativity and small noncommutativity. The strong subadditivity inequality for the entanglement entropies in the noncommutative Yang-Mills theory is modified in large noncommutativity. The behavior of the entropic $c$-function defined by means of the entanglement entropy also changes drastically between large noncommutativity and small noncommutativity. In addition, there is a transition for the entanglement entropy in the noncommutative Yang-Mills theory at finite temperature.

Ab initio methods using weakly interacting nucleons give a good description of condensed nuclear matter up to densities comparable to the nuclear saturation density. At higher densities strong interactions between overlapping nucleons become important; we propose that the interactions will continuously switch over to follow a holographic model in this region. In order to implement this, we construct hybrid equations of state (EOSs) where various models are used for low-density nuclear matter, and the holographic V-QCD model is used for nonperturbative high-density nuclear matter as well as for quark matter. We carefully examine all existing constraints from astrophysics of compact stars and discuss their implications for the hybrid EOSs. Thanks to the stiffness of the V-QCD EOS for nuclear matter, we obtain a large family of viable hybrid EOSs passing the constraints. We find that quark matter cores in neutron stars are unstable due to the strongly first-order deconfinement transition and predict bounds on the tidal deformability as well as on the radius of neutron stars. By relying on universal relations, we also constrain characteristic peak frequencies of gravitational waves produced in neutron star mergers.

We analyze potential violations of causality in Unruh DeWitt-type detector models in relativistic quantum information. We proceed by first studying the relation between faster-than-light signaling and the causal factorization of the dynamics for multiple detector-field interactions. We show in what way spatially extended nonrelativistic detector models predict superluminal propagation of the field’s initial conditions. We draw parallels between this characteristic of detector models, stemming from their nonrelativistic dynamics, and Sorkin’s “impossible measurements on quantum fields” [R. D. Sorkin, in Directions in General Relativity: Proceedings of the 1993 International Symposium, Maryland (Cambridge University Press, 1993), Vol. 2, pp. 293–305.]. Based on these features, we discuss the validity of measurements in quantum field theory when performed with nonrelativistic particle detectors.