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The article discusses a paper published by E. Pourjafarabadi and A. Mojavezi in 2022, which claims to present a new mechanism for gamma-ray absorption by heavy electrons. However, the article points out that the paper does not actually describe this mechanism and fails to acknowledge the prior work of Widom and Larsen, who have already described such a mechanism. Widom and Larsen's work involves the absorption of hard gamma photons by heavy-mass surface plasmon polariton (SPP) electrons. The authors of the article argue that Pourjafarabadi and Mojavezi have not provided a novel mechanism, but have instead discussed the mass renormalization process described by Widom and Larsen. [Extracted from the article]

This paper investigates the disparity between matter and antimatter in the universe with the help of gravitational baryogenesis. This phenomenon commenced shortly after the big bang, resulting in a predominance of matter over antimatter. We analyze the mechanism of gravitational baryogenesis (baryon to entropy ratio) under the framework of f(Q, C) gravity, where Q indicates non-metricity scalar and C denotes the boundary term. This Phenomenon depends on the charge parity violation interaction and for this paper we produce it with the coupling between baryon matter current ( j ν ) and ∂ ν (Q + C) . In the present work, we evaluate he baryon to entropy ratio ( η B S ) by proposing two models of f(Q, C) with the assumption of power-law scale factor for each model and the universe contains perfect fluid throughout. We find that under optimal choice of model parameters, the results of η B S of propose models in f(Q, C) are compatible with the observational bound. The crux of the current work is that the outcomes of our propose models for generalized case of gravitational baryogenesis are consist with its observational constraint in different eras of the Universe. [ABSTRACT FROM AUTHOR]

The behavior of quark matter with both external electric field and chiral chemical potential is theoretically and experimentally interesting to consider. In this paper, the case of simultaneous presence of imaginary electric field and chiral chemical potential is investigated using the lattice QCD approach with N f = 1 + 1 dynamical staggered fermions. We find that overall both the imaginary electric field and the chiral chemical potential can exacerbate chiral symmetry breaking, which is consistent with theoretical predictions. However we also find a non-monotonic behavior of chiral condensation at specific electric field strengths and chiral chemical potentials. The behavior of Polyakov loop in the complex plane is not significantly affected by chiral chemical potential in the region of the parameters considered. [ABSTRACT FROM AUTHOR]

This paper presents a world-leading scintillation light yield among inorganic crystals measured from a 0.5 kg pure-CsI detector operated at 77 Kelvin. Scintillation photons were detected by two 2-inch Hamamatsu SiPM arrays equipped with cryogenic front-end electronics. Benefiting the light yield enhancement of pure-CsI at low temperatures and the high photon detection efficiency of SiPM, a light yield of 30.1 photoelectrons per keV energy deposit was obtained for X-rays and γ -rays with energies from 5.9 to 59.6 keV. Instrumental and physical effects in the light yield measurement are carefully analyzed. This is the first stable cryogenic operation of kg-scale pure-CsI crystal readout by SiPM arrays at liquid nitrogen temperatures for several days. The world-leading light yield opens a door for the usage of pure-CsI crystal in several fields, particularly in detecting the coherent elastic neutrino-nucleus scattering of reactor neutrinos. The potential of using pure-CsI crystals in neutrino physics is discussed in the paper. [ABSTRACT FROM AUTHOR]

In this paper, we compare and contrast the classical versus quantum dynamics of a cosmological model based on the literature (Modified) Berthelot equation of state for the description of the dark sector of the universe. At the classical background level we identify a Minkowski-like and a de Sitter-like equilibrium epochs, with the latter occurring only beyond a certain threshold for a parameter in the equation of state; at the classical perturbed level we find that this same parameter realizes a duality in the adiabatic speed of sound between the two equilibrium epochs. The quantum evolution of this model is studied in the context of quantum geometrodynamics by solving analytically the Wheeler–DeWitt equation in the Born–Oppenheimer approximation for the scalar field potentials about the two equilibrium epochs. We identify the phenomenon of quantum decoherence to arise at the same threshold which constitutes the bifurcation between the two equilibrium epochs at the classical level. We comment on the quantum modified power spectrum focusing on some consequences dealing with the formation of astrophysical structures within the Press–Schechter framework. Our paper is intended to scrutinize which classical features of a certain cosmological model are preserved at its quantum level, and under which assumptions. [ABSTRACT FROM AUTHOR]

This paper is a write-up of the ideas that were presented, developed and discussed at the fourth International Workshop on QCD Challenges from pp to AA, which took place in February 2023 in Padua, Italy. The goal of the workshop was to focus on some of the open questions in the field of high-energy heavy-ion physics and to stimulate the formulation of concrete suggestions for making progresses on both the experimental and theoretical sides. The paper gives a brief introduction to each topic and then summarizes the primary results. [ABSTRACT FROM AUTHOR]

The Pythia8/Angantyr model for heavy ion collisions was recently updated with a mechanism for global colour reconnection. The colour reconnection model used is QCD colour algebra inspired and enhances baryon production due to the formation of string junctions. In this paper, we present updates to the junction formation and string fragmentation mechanisms, connected to heavy quark fragmentation. This allows for the simulation of heavy quark fragmentation, using junction formation, in heavy ion collisions. The framework is validated for proton collisions, and we show results for charm baryon production in proton-lead collisions. [ABSTRACT FROM AUTHOR]

In this paper we investigate the bosonic current induced by a brane and a magnetic flux running along the idealized cosmic string in a (D + 1) -dimensional anti-de Sitter (AdS) background. We consider the brane is parallel to the AdS boundary and the cosmic string is orthogonal to them. Moreover, we assume that on the brane the charged bosonic field obeys the Robin boundary condition. The brane divides the space into two regions with different properties of the vacuum state. We show that the only nonzero component of the current density is along the azimuthal direction in both regions. In order to develop this analysis we calculate, for both regions, the positive frequency Wightman functions. Both functions present a part associated with the AdS in presence of a cosmic string only, and the other part induced by the brane. In this paper we consider only the contributions induced by the brane. We show that in both regions the azimuthal current densities are odd functions of the magnetic flux along the string. Different analytic and numerical analysis are performed and an application of our results is provided for the Randall-Sundrum braneworld model with a single brane. [ABSTRACT FROM AUTHOR]

The general theory of relativity predicts the relativistic effect in the orbital motions of S-stars which are orbiting around our Milky-way Galactic Center. The post-Newtonian or higher-order approximated Schwarzschild black hole models have been used by GRAVITY and UCLA Galactic Center groups to carefully investigate the S2 star's periastron precession. In this paper, we investigate the scalar field effect on the orbital dynamics of S2 star. Hence, we consider a spacetime, namely Janis-Newman-Winicour (JNW) spacetime which is seeded by a minimally coupled, mass-less scalar field. The novel feature of this spacetime is that one can retain the Schwarzschild spacetime from JNW spacetime considering zero scalar charge. We constrain the scalar charge of JNW spacetime by best fitting the astrometric data of S2 star using the Monte-Carlo–Markov-Chain (MCMC) technique assuming the charge to be positive. Our best-fitted result implies that similar to the Schwarzschild black hole spacetime, the JNW naked singularity spacetime with an appropriate scalar charge also offers a satisfactory fitting to the observed data for S2 star. Therefore, the JNW naked singularity could be a contender for explaining the nature of Sgr A* through the orbital motions of the S2 star. [ABSTRACT FROM AUTHOR]

In this paper we study meson scattering in a non-minimally Lorentz-violating scalar QED at finite temperature. The meson scatterings were investigated in tree level and the finite temperature effects were addressed by using the thermofield dynamics formalism. We have considered three types of scattering, namely, meson-antimeson of a-type into meson-antimeson of b-type, meson-antimeson of a-type into meson-antimeson of a-type and meson-meson of a-type into meson-meson of a-type. For each scattering we have computed the cross section in order to investigate the influence of the finite temperature effects. [ABSTRACT FROM AUTHOR]

Recent data from elliptical galaxies indicate that the growth in the masses of black holes exceeds what is expected from the accretion of surrounding matter, and this growth appears to be dependent on the expansion of the universe. This phenomenon can be explained by considering the accretion of dark energy, which is responsible for cosmological expansion, into these black holes. In this paper, we investigate the perturbative interaction of a black hole with a real scalar field ϕ (which can represent dark energy) in a cosmological background using an appropriate metric. We derive solutions for the field ϕ (t , r) , the black hole mass M(t), and the expansion rate H(t), and discuss the behaviour of the scalar field ϕ in the vicinity of the black hole, with respect to exterior and interior observers. [ABSTRACT FROM AUTHOR]

Realistic quantum systems are affected by the expanding universe in their preparation and quantum information processing. In this paper, we study the relationship between the Gaussian quantum steering distribution and the parameters of the expanding universe. The expansion process of the universe can be described as a channel acting on a two-mode squeezed Gaussian state, with the evolution of quantum steering from the asymptotic past to the asymptotic future resulting in new distributions parameterized by cosmic parameters. We find that Gaussian quantum steering is more sensitive to the volume change of the expanding universe than the expansion rate, and the Gaussian quantum steering generated by particles with suitable mass and small momentum is more affected by the expanding universe. [ABSTRACT FROM AUTHOR]

The current upper limit on N eff at the time of CMB by Planck 2018 can place stringent constraints in the parameter space of BSM paradigms where their additional interactions may affect neutrino decoupling. Motivated by this fact in this paper we explore the consequences of light gauge boson ( Z ′ ) emerging from local U (1) X symmetry in N eff at the time of CMB. First, we analyze the generic U (1) X models with arbitrary charge assignments for the SM fermions and show that, in the context of N eff the generic U (1) X gauged models can be broadly classified into two categories, depending on the charge assignments of first generation leptons. We then perform a detailed analysis with two specific U (1) X models: U (1) B 3 - 3 L e and U (1) B 3 - 3 L μ and explore the contribution in N eff due to the presence of Z ′ realized in those models. For comparison, we also showcase the constraints from low energy experiments like: Borexino, Xenon 1T, neutrino trident, etc. We show that in a specific parameter space, particularly in the low mass region of Z ′ , the bound from N eff (Planck 2018) is more stringent than the experimental constraints. Additionally, a part of the regions of the same parameter space may also relax the H 0 tension. [ABSTRACT FROM AUTHOR]

The massless fields in the universal NS-NS sector of string theory form O(D, D) multiplets of Double Field Theory, which is a theory that provides a T-duality covariant formulation of supergravity, leading to a stringy modification of General Relativity. In this framework, it is possible to write down the extensions of the Einstein field equations and the Friedmann equations in such a way that the coupling of gravitational and matter sectors is dictated by the O(D, D) symmetry universally. In this paper, we obtain the autonomous form of the O(D, D)-complete Friedmann equations, find the critical points and perform their stability analysis. We also include the phase portraits of the system. Cosmologically interesting cases of scalar field, radiation, and matter are separately considered and compared with the Chameleon models in a similar setting. Accelerating phases and the conditions for their existence are also given for such cases. [ABSTRACT FROM AUTHOR]

In this paper, we investigate symmetry-resolved entanglement entropy (SREE) in free bosonic quantum many-body systems. Utilizing a lattice regularization scheme, we compute symmetry-resolved Rényi entropies for free complex scalar fields and a specific class of non-local field theories, where entanglement entropy (EE) exhibits volume-law scaling. We present effective and approximate eigenvalues for the correlation matrix used in computing SREE and demonstrate their consistency with numerical results. Furthermore, we explore the equipartition of EE, verifying its effective behavior in the massless limit. Finally, we comment on EE in non-local quantum field theories and provide an explicit expression for the symmetry-resolved Rényi entropies. [ABSTRACT FROM AUTHOR]

The search of the new physics (NP) beyond the Standard Model is one of the most important topics in current high energy physics. With the increasing luminosities at the colliders, the search for NP signals requires the analysis of more and more data, and the efficiency in data processing becomes particularly important. As a machine learning algorithm, support vector machine (SVM) is expected to to be useful in the search of NP. Meanwhile, the quantum computing has the potential to offer huge advantages when dealing with large amounts of data, which suggests that quantum SVM (QSVM) is a potential tool in future phenomenological studies of the NP. How to use SVM and QSVM to optimize event selection strategies to search for NP signals are studied in this paper. Taking the tri-photon process at a muon collider as an example, it can be shown that the event selection strategies optimized by the SVM and QSVM are effective in the search of the dimension-8 operators contributing to the anomalous quartic gauge couplings. [ABSTRACT FROM AUTHOR]

The Sen formulation for chiral (2p)-form in 4 p + 2 dimensions describes a system with two separate sectors, one is physical while the other is unphysical. Each contains a chiral form and a metric. In this paper, we focus on the cases where the self-duality condition for the unphysical sector is linear while for the physical sector can be nonlinear. We show the decoupling at the Hamiltonian and Lagrangian levels. The decoupling at the Hamiltonian level follows the idea in the literature. Then by an appropriate field redefinition of the corresponding first-order Lagrangian, the separation at the Lagrangian level follows. We derive the diffeomorphism of the theory in the case where the chiral form in the physical sector has nonlinear self-dual field strength and couples to external (2 p + 1) -form field. Explicit forms of Sen theories are also discussed. The Lagrangian for the quadratic theory is separated into two Henneaux–Teitelboim Lagrangians. We also discuss the method of generating explicit nonlinear theories with p = 1 . Finally, we also show that the M5-brane action in the Sen formulation is separated into a Henneaux–Teitelboim action in unphysical sector and a gauge-fixed PST in physical sector. [ABSTRACT FROM AUTHOR]

In this paper, we calculated the extreme mass-ratio inspiral (EMRI) waveform radiated from a binary composed of a massive horizonless object (MHO) and a compact object (CO), where CO is spiraling on a circular equatorial orbit around the MHO. Due to the absent of horizon, there exist the ingoing and outgoing waves near the reflective surface of MHO, which have significantly influence on the evolution of orbital parameters. We observe that there indeed exist the differences of EMRI trajectories between the massive Kerr black hole and MHO cases. By calculating the mismatch of gravitational wave (GW) waveforms from massive black hole (MBH) and MHO, our result indicates that the space-borne gravitational wave detector could distinguish the modified effect of reflectivities from the BH case, which allows to put an upper constraint on the reflectivity R of MHO, at the level of R ≳ 10 - 4 . [ABSTRACT FROM AUTHOR]

This paper investigates the generation and properties of gravitational radiation within the framework of generalized Brans–Dicke (GBD) theory, with a specific emphasis on its manifestation in compact binary systems. The study begins by examining the weak field equations in GBD theory, laying the foundation for subsequent analyses. Solutions to the linearized field equations for point particles are then presented, providing insights into the behavior of gravitational fields in the context of GBD theory. The equation of motion of point mass is explored, shedding light on the dynamics of compact binary systems within the GBD framework. The primary focus of this study lies in the comprehensive exploration of gravitational radiation generated by compact binaries. The energy momentum tensor and the associated gravitational wave (GW) radiation power in GBD theory are investigated, elucidating the relationship between these fundamental concepts. Furthermore, detailed calculations are provided for the GW radiation power originating from both tensor fields and scalar fields. Based on our calculations, both scalar fields contribute to GW radiation by producing dipole radiation. We also study the period derivative of compact binaries in this theory. By comparing with the observational data of the orbital period derivative of the quasicircular white dwarf-neutron star binary PSR J1012+5307, we put bounds on the two parameters of the theory: the Brans–Dicke coupling parameter ω 0 and the mass of geometrical scalar field m f , resulting in a lower bound ω 0 > 6.09723 × 10 6 for a massless BD scalar field and the geometrical field whose mass is smaller than 10 - 29 GeV . The obtained bound on ω 0 is two orders of magnitude stricter than those derived from solar system data. Finally, we find the phase shift that GWs experience in the frequency domain during their propagation. These calculations offer a quantitative understanding of the contributions from different components within the GBD theory, facilitating a deeper comprehension of the overall behavior and characteristics of gravitational radiation. [ABSTRACT FROM AUTHOR]

The Yang algebra was proposed a long time ago as a generalization of the Snyder algebra to the case of curved background spacetime. It includes as subalgebras both the Snyder and the de Sitter algebras and can therefore be viewed as a model of noncommutative curved spacetime. A peculiarity with respect to standard models of noncommutative geometry is that it includes translation and Lorentz generators, so that the definition of a Hopf algebra and the physical interpretation of the variables conjugated to the primary ones is not trivial. In this paper we consider the realizations of the Yang algebra and its κ -deformed generalization on an extended phase space and in this way we are able to define a Hopf structure and a twist. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the polarization images of a synchrotron-emitting fluid ring surrounding a static hairy black hole within the framework of Horndeski’s theory. Our findings indicate that the characteristics of these polarization images are predominantly influenced by the hairy parameter, alongside the magnetic field near the black hole, the fluid’s velocity, and the observer’s inclination angle. Specifically, the hairy parameter primarily affects the polarized intensity and the apparent radius of the ring in the images. Conversely, the impacts of the magnetic field, fluid velocity, and inclination angle on the polarization images are found to be independent of the hairy parameter and closely resemble those observed in the context of Schwarzschild black holes. Additionally, the polarization direction is significantly influenced by the magnetic field orientation, while the inclination angle crucially determines the apparent flatness of the images. Variations in the fluid velocity direction also markedly affect the trend in polarized intensity. Furthermore, we explore how these parameters influence the Stokes Q - U loops, revealing distinct behaviors in response to changes in the aforementioned variables. This comprehensive analysis enhances our understanding of the intricate dynamics and observational signatures of black holes within alternative gravitational theories. [ABSTRACT FROM AUTHOR]

In this paper, we revisit the model-independent reconstruction of f(T) and f(R) gravity at the cosmological background and linear matter density perturbation levels respectively via Gaussian process by using the currently available cosmic observations, which consist Pantheon+ SNe Ia samples, observed Hubble parameter H(z) and the redshift space distortion f σ 8 (z) data points. For the f(T) gravity, we find the reconstructed form of f(T) from the background and perturbation levels cannot match each other well in 1 σ regions, it might imply the tension between the background and perturbation evolutions. For the f(R) gravity, due to the existence of an extra degree for freedom F ˙ , the form of f(R) can be reconstructed by the addition of the growth rate function. The results show that the reconstructed form of f(R) might be viable in the redshift range of z < 0.75 based on the currently available cosmic observations, for filling the requirement of f , R > 0 and f , R R > 0 to avoid a tachyonic instability and be ghosts free in theory. [ABSTRACT FROM AUTHOR]

The statefinder diagnostic is useful to discriminate dark energy models. In this paper, under the minimum assumption of a spatially flat Friedmann–Lemaître–Robertson–Walker Universe, we reconstruct the statefinder pair { r (z) , s (z) } in addition to the deceleration parameter q(z) via the Gaussian process from the cosmic observational data points which include the recently released Pantheon+ SN Ia samples and the observational Hubble data H(z). The reconstructed evolution trajectories are shown on the r - q , r - s planes. The reconstructed q(z) is consistent with previous studies. Meanwhile, a novel quantity named suitability is introduced on the r - q , r - s planes to assess the validation of a dark energy model. [ABSTRACT FROM AUTHOR]

In this paper, we present analytical solutions to the Einstein field equations for spherically symmetric anisotropic matter distributions using the well-established Tolman VII metric potential, chosen for its strong physical and mathematical foundations. Our solutions are derived using three distinct approaches: the vanishing complexity factor condition (VCC), the embedding class I condition (ECC), and the conformally flat condition (CFC). We conduct a comprehensive comparative analysis of these three approaches. By ensuring a smooth match between the interior spacetime metric and the exterior Schwarzschild metric, and applying the condition of vanishing radial pressure at the boundary, we determine the model parameters. We graphically assess the model’s stability by examining conditions such as causality, the adiabatic index, equations of state, and the generalized Tolman–Oppenheimer–Volkov (TOV) equation, considering the forces acting within the system. Additionally, the effects of anisotropy on the stars’ physical characteristics are investigated through graphical representations. [ABSTRACT FROM AUTHOR]

In this paper, we explore the existence of various non-singular compact stellar solutions influenced by the Maxwell field within the matter-geometry coupling based modified gravity. We start this analysis by considering a static spherically symmetric spacetime which is associated with the isotropic matter distribution. We then determine the field equations corresponding to two specific functions of this modified theory. Along with these models, we also adopt different forms of the matter Lagrangian. We observe several unknowns in these equations such as the metric potentials, charge and fluid parameters. Thus, the embedding class-one condition and a particular realistic equation of state is used to construct their corresponding solutions. The former condition provides the metric components possessing three constants, and we calculate them through junction conditions. Further, four developed models are graphically analyzed under different parametric values. Finally, we find all our developed solutions well-agreeing with the physical requirements, offering valuable insights for future explorations of the stellar compositions in this theory. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the topological numbers of the four-dimensional Schwarzschild black hole, d-dimensional Reissner–Nordström (RN) black hole, d-dimensional singly rotating Kerr black hole and five-dimensional Gauss–Bonnet black hole via the Rényi statistics. We find that the topological number calculated via the Rényi statistics is different from that obtained from the Gibbs–Boltzmann (GB) statistics. However, what is interesting is that the topological classifications of different black holes are consistent in both the Rényi and GB statistics: the four-dimensional RN black hole, four-dimensional and five-dimensional singly rotating Kerr black holes, five-dimensional charged and uncharged Gauss–Bonnet black holes belong to the same kind of topological class, and the four-dimensional Schwarzschild black hole and d (> 5) -dimensional singly rotating Kerr black holes belong to another kind of topological class. In addition, our results suggest that the topological numbers calculated via the Rényi statistics in asymptotically flat spacetime background are equal to those calculated from the standard GB statistics in asymptotically AdS spacetime background, which provides more evidence for the connection between the nonextensivity of the Rényi parameter λ and the cosmological constant Λ . [ABSTRACT FROM AUTHOR]

The Friedberg–Lee–Sirlin (FLS) model is a well-known renormalizable theory of scalar fields that provides for the existence of non-topological solitons. Since this model was proposed, numerous works have been dedicated to studying its classical configurations and its general suitability for various physical problems in cosmology, quantum chromodynamics, etc. In this paper, we study how Q-balls in effective field theory (EFT) reproduce non-topological solitons in the full FLS theory. We obtain an analytical description of the simplified model and compare the results with numerical calculations and perturbation theory. We also study the condensation of charged bosons on the domain wall. A full numerical solution allows us to check the EFT methods for this problem. The latter analysis is based on the application of EFT methods to significantly inhomogeneous configurations. We give an interpretation of the results in terms of the shifted boson mass and the vacuum rearrangement. [ABSTRACT FROM AUTHOR]

In this paper we develop a method to obtain the rates for the decay of a Z boson into fermions in de Sitter geometry. Our general results obtained in de Sitter space-time allow us to obtain the Minkowski limits for the transition rates when the expansion parameter vanishes. Another important result reported in the present study is related to the emission of Z bosons by electrons and positrons. All the processes were studied by implementing perturbative methods that allow us to define the transition amplitudes in the first order of perturbation theory. The variation of probabilities and rates in terms of expansion parameter and particles masses is also given, pointing out that the processes that generate particle production are possible only in the early universe. For computing the transition rates and probabilities we use the dimensional regularization method and the minimal substraction method. [ABSTRACT FROM AUTHOR]

Recent studies have increasingly focused on the effect of relativistic motion on quantum coherence. Prior research predominantly examined the influence of relative motion on basis-dependent quantum coherence, underscoring its susceptibility to decoherence under accelerated conditions. Yet, the effect of relativistic motion on basis-independent quantum coherence, which is critical for understanding the intrinsic quantum features of a system, remains an interesting open question. This paper addresses this question by examining how total, collective, and localized coherence are affected by acceleration and coupling strength. Our analysis reveals that both total and collective coherence significantly decrease with increasing acceleration and coupling strength, ultimately vanishing at high levels of acceleration. This underscores the profound impact of Unruh thermal noise. Conversely, localized coherence exhibits relative stability, decreasing to zero only under the extreme condition of infinite acceleration. Moreover, we demonstrate that collective, localized, and basis-independent coherence collectively satisfy the triangle inequality. These findings are crucial for enhancing our understanding of quantum information dynamics in environments subjected to high acceleration and offer valuable insights on the behavior of quantum coherence under relativistic conditions. [ABSTRACT FROM AUTHOR]

In this paper, we study the reentrant Hawking–Page transition in the grand canonical ensemble of Gauss–Bonnet AdS spacetime. We find that the four-dimensional Gauss–Bonnet hyperbolic AdS black hole always has a reentrant Hawking–Page transition in the range of electric potential 0 < Φ < Φ tr , accompanied by the appearance of the triple point. However, once the potential exceeds a certain upper limit Φ tr , i.e. Φ > Φ tr , the Hawking–Page transition disappears. In the spacetime of five and higher dimensional Gauss–Bonnet hyperbolic AdS black hole, the reentrant Hawking–Page transition is solely observed to occur when the electric potential Φ lies between two specific thresholds ( Φ c < Φ < Φ tr ). In scenarios where the electric potential is below Φ c ( Φ < Φ c ), only the standard Hawking–Page transition as in the the Einstein gravity is observed. Similar to the four-dimensional case, the Hawking–Page transition is negated when the electric potential exceeds Φ tr ( Φ > Φ tr ). We give the coexistence line, the triple point and critical point of the Hawking–Page transition in the phase diagram of the Gauss–Bonnet hyperbolic AdS black hole. The observed reentrant Hawking–Page transitions and triple points in the context of Gauss–Bonnet hyperbolic AdS black holes may correspond to the phase transitions and triple points in QCD phase diagrams, following the spirit of the AdS/CFT correspondence. To be a complete research, the Hawking–Page transition of d-dimensional charged spherical Gauss–Bonnet-AdS black hole in the grand canonical ensemble is also study in the Appendix, for which there exists a standard Hawking–Page transition with the transition temperature depending on the Gauss–Bonnet constant α . [ABSTRACT FROM AUTHOR]

In this paper, we present a cosmological model within the framework of symmetric teleparallel gravity, focusing on f(Q) gravity, where Q represents the non-metricity scalar. Utilizing cosmological datasets, we derive an accelerating cosmological model by constraining its free parameters. To achieve this, we determine the parametric form of the Hubble parameter using a well-motivated f(Q) function. Remarkably, all obtained values fall within the range suggested by cosmological observations. By employing the best-fit parameters, we calculate the present geometrical parameters and demonstrate the accelerating behaviour of the Universe. Furthermore, we thoroughly examine the evolutionary behaviours of the Universe, noting that our model converges to the Λ CDM model at late times. Finally, we investigate the energy conditions and find a violation of the strong energy condition, which could provide a valuable understanding of the nature of dark energy. [ABSTRACT FROM AUTHOR]

Extended teleparallel gravity, characterized by function F(Q), where Q is the non-metricity scalar, is one of the most promising approaches to general relativity. In this paper, we reexamine a specific dynamical dark energy model, which is indistinguishable from the Λ CDM model at the present time and exhibits a special event in the future, within F(Q) gravity. To constrain the free parameters of the model, we perform Markov chain Monte Carlo (MCMC) analysis, using the last data from Pantheon + and the latest measurements of the H(z) parameter, combined. On the basis of this analysis, we find that our dynamical dark energy model, in the context of F(Q) gravity, lies in the quintessence regime rather than in the phantom regime, as in the case of general relativity. Furthermore, this behavior affects the future expansion of the Universe, as it becomes decelerating at a 1 σ confidence level for z < - 0.5 , showing a bounce at z B ≈ - 0.835 . We support our conclusion with a cosmographic analysis. [ABSTRACT FROM AUTHOR]

This paper investigates the axial gravitational perturbations originating from spherically symmetric black holes in f(R) gravity, along with the optical appearance of such a black hole. The aim is to search for evidence of the existence of these black holes in astrophysical observations and thereby test the correctness of the f(R) theory. In literature Kalita and Mukhopadhyay (Eur Phys J C 79:877, 2019), the spherically symmetric black hole metric in f(R) gravity is obtained. By comparing it with the metric for spherically symmetric black holes in general relativity, we find that the modification of gravity due to f(R) can be described in this black hole spacetime using a parameter C f . Next, we study axial gravitational perturbations in this spacetime and successfully derive a decoupled axial perturbation equation. We also discuss the impact of f(R) gravity on the quasi-normal mode frequencies. Additionally, we have also investigated the optical appearance of the black hole. We discuss the impact of the parameter C f on the observable characteristics of the accretion disk. In principle, both of these effects can be observed using gravitational wave detectors and astronomical telescopes. [ABSTRACT FROM AUTHOR]

The unfolding of detector effects is a key aspect of comparing experimental data with theoretical predictions. In recent years, different Machine-Learning methods have been developed to provide novel features, e.g. high dimensionality or a probabilistic single-event unfolding based on generative neural networks. Traditionally, many analyses unfold detector effects using transfer-matrix-based algorithms, which are well established in low-dimensional unfolding. They yield an unfolded distribution of the total spectrum, together with its covariance matrix. This paper proposes a method to obtain probabilistic single-event unfolded distributions, together with their uncertainties and correlations, for the transfer-matrix-based unfolding. The algorithm is first validated on a toy model and then applied to pseudo-data for the p p → Z γ γ process. In both examples the performance is compared to the Machine-Learning-based single-event unfolding using an iterative approach with conditional invertible neural networks (IcINN). [ABSTRACT FROM AUTHOR]

In this paper, we investigate the quasi-two-body decays B c → K 0 ∗ (1430 , 1950) D (s) → K π D (s) within the perturbative QCD (PQCD) framework. The S-wave two-meson distribution amplitudes (DAs) are introduced to describe the final state interactions of the K π pair, which involve the time-like form factors and the Gegenbauer polynomials. In the calculations, we adopt two kinds of parameterization schemes to describe the time-like form factors: one is the relativistic Breit–Wigner (RBW) formula, which is usually more suitable for the narrow resonances, and the other is the LASS line shape proposed by the LASS Collaboration, which includes both the resonant and nonresonant components. We find that the branching ratios and the direct CP violations for the decays B c → K 0 ∗ (1430) D (s) obtained from those of the quasi-two-body decays B c → K 0 ∗ (1430) D (s) → K π D (s) under the narrow width approximation (NWA) can be consistent well with the previous PQCD results calculated in the two-body framework by assuming that K 0 ∗ (1430) is the lowest lying q ¯ s state, which is the so-called scenario II (SII). We conclude that the LASS parameterization is more suitable to describe the K 0 ∗ (1430) than the RBW formula, and the nonresonant components play an important role in the branching ratios of the decays B c → K 0 ∗ (1430) D (s) → K π D (s) . In view of the large difference between the decay width measurements for the K 0 ∗ (1950) given by BaBar and LASS collaborations, we calculate the branching ratios and the CP violations for the quasi-two-body decays B c → K 0 ∗ (1950) D (s) → K π D (s) by using two values, Γ K 0 ∗ (1950) = 0.100 ± 0.04 GeV and Γ K 0 ∗ (1950) = 0.201 ± 0.034 GeV, besides the two kinds of parameterizations for the resonance K 0 ∗ (1950) . We find that the branching ratios and the direct CP violations for the decays B c → K 0 ∗ (1950) D (s) → K π D (s) have not as large difference between the two parameterizations as the case of decays involving the K 0 ∗ (1430) , especially for the results with Γ K 0 ∗ (1950) = 0.201 ± 0.034 GeV. The effect of the nonresonant component in the K 0 ∗ (1950) may be not so serious as that in the K 0 ∗ (1430) . The quasi-two-body decays B c + → K 0 ∗ + (1430) D 0 → K 0 π + D 0 and B c + → K 0 ∗ 0 (1430) D + → K + π - D + have large branching ratios, which can reach to the order of 10 - 4 and are most likely to be observed in the future LHCb experiments. Furthermore, the branching ratios of the quasi-two-body decays B c → K 0 ∗ (1950) D (s) → K π D (s) are about one order smaller than those of the corresponding decays B c → K 0 ∗ (1430) D (s) → K π D (s) . [ABSTRACT FROM AUTHOR]

The Kerr/CFT correspondence has been established to explore the quantum theory of gravity in the near-horizon geometry of an extreme Kerr black holes. The quantum gravitational corrections on the near-horizon region may manifest in form of a partially reflective membrane that replace the horizon. In such modification, the black holes now can be seen as a horizonless exotic compact object (ECO). In this paper, we consider the properties of Kerr-like ECOs in near-extremal condition using Kerr/CFT correspondence. We study the quasinormal modes and absorption cross-section in that background and compare these by using CFT dual computation. The corresponding dual CFT one needs to incorporate finite size/finite N effects in the dual CFT terminology. We also extend the dual CFT analysis for higher spin perturbations such as photon and graviton. We find consistency between properties of the ECOs from gravity sides and from CFT sides. The quasinormal mode spectrum is in line with non-extreme case, where the differences are in the length of the circle, on which the dual CFT lives, and phase shift of the incoming perturbation. The absorption cross-section has oscillatory feature that start to disappear near extremal limit. The particle spin determines the phase shift and conformal weight. We also obtain that the echo time-delay depends on the position of the membrane and extremality of the ECOs. [ABSTRACT FROM AUTHOR]

In the quest for direct dark matter detection, innovative approaches to lower the detection threshold and explore the sub-GeV mass range, have gained high relevance in the last decade. This study presents the pioneering use of Gallium Arsenide (GaAs) as a low-temperature calorimeter for probing dark matter-electron interactions within the DAREDEVIL (DARk-mattEr DEVIces for Low energy detection) project. Our experimental setup features a GaAs crystal at an ultralow temperature of 15 mK, coupled with a Neutron Transmutation Doped Germanium (NTD-Ge) thermal sensor for precise energy estimation. This configuration is the first step towards detecting single electrons scattered by dark matter particles within the GaAs crystal, to improve the sensitivity to low-mass dark matter candidates significantly. Taking advantage of the production of optical phonons in polar materials such as GaAs gives the possibility to study the scattering of sub-MeV dark matter. This paper presents a detailed analysis of the detector’s response, using a calibration spectrum using α particles and X-ray events. While the results do not meet the ambitious eV scale threshold yet, they establish a solid benchmark for assessing the detector’s current performance and sensitivity. This work not only highlights the detector’s potential but also sets the stage for future enhancements aimed at achieving the eV threshold, underscoring the promising direction of this detector technology. These findings demonstrate the feasibility of using GaAs as a cryogenic calorimeter and hence open new avenues for investigating the elusive nature of dark matter through innovative direct detection techniques. [ABSTRACT FROM AUTHOR]

One of the main issues in gravitation is the presence of singularities in the most common space-time solutions of General Relativity, as the case of black holes. A way of constructing regular solutions that remove spacelike singularities consists in implement a bounce on such space-time, leading to what is usually known as black bounce space-times. Such space-times are known to describe regular black holes or traversable wormholes. However, one of the main issues lies on reconstructing the appropriate source that leads to such a solution. In this paper, a reconstruction method is implemented to show that such types of metrics can be well accommodated in non-linear electrodynamics with the presence of a scalar field. Some of the most important black bounces solutions are reconstructed in this framework, both in 3 + 1 as in 2 + 1 dimensions. For the first time in the literature, these solutions have an electrically charged source of matter from non-linear electrodynamics. Specific features are indicated that distinguish electric sources from magnetic ones, previously found for the same space-times. [ABSTRACT FROM AUTHOR]

Reference (Pittau and Webber in Eur Phys J C 82(1):55, , 2022) introduces a method for computing numerically four-dimensional multi-loop integrals without performing an explicit analytic contour deformation around threshold singularities. In this paper, we extend such a technique to massless scalar one-loop integrals regularized in the framework of dimensional regularization. A two-loop example is also discussed. [ABSTRACT FROM AUTHOR]

In this paper, we propose an approach to derive the brane cosmology in the D-dimensional braneworld model. We generalize the “bulk-based” approach by treating the 4-brane as a small perturbation to the D-dimensional spherically symmetric spacetime. The linear corrections from a static 4-brane to the metric are derived from the linearized perturbation equations, while the nonlinear corrections are found by a parameterization of the perturbed metric solution. We use a time-dependent generalization to give the nonlinearly perturbed metric solution for the dynamical braneworld model, and analyze the stability of the model under the motion of the 4-brane. Through the fine tuning, we can recover the Friedmann equations for the universe with and without an effective cosmological constant. More importantly, the de Sitter expansion of the universe can be reproduced. [ABSTRACT FROM AUTHOR]

In this paper, we obtain a complete list of stationary and axisymmetric spacetimes, generated from a Minkowski spacetime using the Ernst technique. We do so by operating on the associated seed potentials with a composition of Ehlers and Harrison transformations. In particular, assigning an additional “electric” or “magnetic” tag to the transformations, we investigate the new spacetimes obtained either via a composition of magnetic Ehlers and Harrison transformations (first part) or via a magnetic-electric combination (second part). In the first part, the resulting type D spacetime, dubbed electromagnetic swirling universe, features key properties, separately found in swirling and (Bonnor–)Melvin spacetimes, the latter recovered in appropriate limits. A detailed analysis of the geometry is included, and subtle issues are addressed. A detailed proof that the spacetime belongs to the Kundt family, is included, and a notable relation to the5 planar-Reissner–Nordström-NUT black hole is also meticulously worked out. This relation is further exploited to reverse-engineer the form of the solution in the presence of a nontrivial cosmological constant. A Schwarzschild black hole embedded into the new background is also discussed. In the second part, we present four novel stationary and axisymmetric asymptotically nonflat type I spacetimes, which are naively expected to be extensions of the Melvin or swirling solution including a NUT parameter or electromagnetic charges. We actually find that they are, under conditions, free of curvature and topological singularities, with the physical meaning of the electric transformation parameters in these backgrounds requiring further investigation. [ABSTRACT FROM AUTHOR]

In this paper, we would like to examine whether stable de Sitter inflationary solutions appear within power-law extensions of the Starobinsky model. In particular, we will address general constraints for the existence along with the stability of de Sitter inflationary solutions in a general case involving not only the Starobinsky R 2 term but also an additional power-law R n one. According to the obtained results, we will be able to identify which extension is more suitable for an early inflationary phase rather than a late-time cosmic acceleration phase. To be more specific, we will consider several values of n to see whether the corresponding de Sitter inflationary solutions are stable or not. [ABSTRACT FROM AUTHOR]

Twist-3 collinear parton distribution functions (PDFs) are matrix elements of quark-gluon-quark or three-gluons light-cone operators. They depend on three momentum fraction variables, which are restricted to a hexagon region, and the evolution kernels are defined via two-dimensional convolution in these variables. We present the numerical realisation of the twist-3 evolution equations at leading order in the strong coupling for all kinds of twist-3 PDF (quark, gluon, chiral-even/odd, etc). We provide two independent codes (in C and Fortran) that have been extensively cross-checked, and are ready-to-use. We supplement the paper with a review of known properties of twist-3 PDFs. [ABSTRACT FROM AUTHOR]

In this paper, the higher-dimensional topological dS black hole with a nonlinear source (HDTNS) is considered. First, we obtain the thermodynamic quantities of the ( n + 1 )-dimensional topological dS black hole, which satisfy the first law of thermodynamics. Second, based on the effective thermodynamic quantities and Maxwell’s equal-area law method, we explore the phase equilibrium for the HDTNS. The boundary of the two-phase coexistence region in the P eff 0 - T eff 0 diagram is obtained. The critical thermodynamic quantities as well as the horizon potential are also investigated. Furthermore, we analyze the effect of parameters (the spacetime dimension n and the ratio of two horizon radii x = r + / r c ) on the boundary of the two-phase coexistence region and study the latent heat of phase transition for this system, which corresponds to the Clapeyron equation. The results indicate that the phase transition in HDTNS spacetime is analogous to that in a van der Waals (vdW) fluid system, which is determined by electrical potential at the horizon. These results help to understand the fundamental properties of black holes. A more intuitive and profound understanding of gravity is gained by studying the thermodynamic properties of different spacetimes. They provide a theoretical basis for an in-depth study of the classical and quantum properties of de Sitter spacetime and its evolution. [ABSTRACT FROM AUTHOR]

In this paper, we extend Chandrasekhar’s method of calculating rotating black holes into f(R) theory. We show that the solution with constant Ricci scalar always exists in a general f(R) gravity and derive the Kerr and Kerr-Ads metric by using the analytical mathematical method. Suppose that the spacetime is a 4-dimensional Riemannian manifold with a general stationary axisymmetric metric, we calculate Cartan’s equation of structure and derive the Einstein tensor. In order to reduce the solving difficulty, we fix the gauge freedom to transform the metric into a more symmetric form. We solve the field equations in the two cases of the Ricci scalar R = 0 and R ≠ 0 . In the case of R = 0 , the Ernst’s equations are derived. We give the elementary solution of Ernst’s equations and show the way to obtain more solutions including Kerr metric. In the case of R ≠ 0 , we reasonably assume that the solution to the equations consists of two parts: the first is Kerr part and the second is introduced by the Ricci scalar. Giving solution to the second part and combining the two parts, we obtain the Kerr-Ads metric. The calculations are carried out in a general f(R) theory. Furthermore, the whole solving process can be treated as a standard calculation procedure to obtain rotating black holes, which can be applied to other modified gravities. [ABSTRACT FROM AUTHOR]

In AdS/CFT, partition functions of decoupled CFTs living on separate asymptotic boundaries factorize. However, the presence of bulk wormholes connecting different boundaries tends to spoil the factorization of the bulk partition function, which leads to a disagreement between the two sides. In this paper, we present two examples where wormhole contributions cancel each other in bulk partition function calculations, thus the bulk factorization can be realized. The first example is in 2-dimensional Jackiw–Teitelboim (JT) gravity, where the proposed way of realizing the cancellation resides in the extra complex phases associated with different wormholes. The phases arise due to the degenerate vacua structure. In the example of the Sachdev–Ye–Kitaev (SYK) model, the cancellation can be achieved due to the distribution of the wormhole saddles on a complex plane. The two examples demonstrate a way of realizing bulk partition function factorization by extending the Hilbert space and dressing wormhole saddles with extra phases. [ABSTRACT FROM AUTHOR]

In standard cosmology, the cosmic homogeneity scale is the transition scale above which the patterns arising from non-uniformities – such as groups and clusters of galaxies, voids, and filaments – become indistinguishable from a random distribution of sources. Recently, different groups have investigated the feasibility of using such a scale as a cosmological test and arrived at different conclusions. In this paper, we complement and extend these studies by exploring the evolution of the spatial ( R H ) and angular ( θ H ) homogeneity scales with redshift, assuming a spatially flat, Λ -Cold Dark Matter universe and linear cosmological perturbation theory. We confirm previous results concerning the non-monotonicity of R H with the matter density parameter Ω m0 but also show that it exhibits a monotonical behavior with the Hubble constant H 0 within a large redshift interval. More importantly, we find that, for z ≳ 0.6 , θ H presents a monotonical behavior with Ω m0 , as well as for H 0 the entire redshift interval analyzed. We find also that the angular homogeneity scale is sensitive to H 0 , especially at higher redshifts. Using the currently available θ H measurements, we illustrate the constraints on the Ω m0 – H 0 plane through a MCMC analysis and show the feasibility of using the angular homogeneity scale as a new, model-independent way to constrain cosmological parameters. [ABSTRACT FROM AUTHOR]

The global monopole solutions which give rise to quite unusual physical phenomena have captured considerable attention. In this paper, we study the Einstein ring of the spherically symmetric AdS black hole solution with a global monopole based on the AdS/CFT correspondence. With the help of the given response function of the QFT on the boundary, we construct the holographic images of the black hole in the bulk. Our results exhibit the absolute amplitude of total response function | ⟨ O ⟩ | increases with the decrease of the monopole parameter b and the temperature T. And the frequency ω of the Gaussian source will also increase the absolute amplitude. These parameters also affects the Einstein ring. With the change of the observation position, this ring will change from the concentric stripe to a luminosity-deformed ring, or light points. And the monopole parameter has an effect on the brightness and the position of Einstein ring. All these results imply that the holographic images can be used as an effective tool to distinguish different types of black holes for fixed wave source and optical system. These theoretical proposal opens a door to gravitational phenomena on strongly correlated material. Therefore, the holographic Einstein ring is of great theoretical and experimental significance for our research. In theory, it provides us a new way to find a necessary condition for the existence of the dual black hole. And experimentally speaking, if we can realize suitable targets for observing AdS black holes successfully, we would be able to observe Einstein rings by tabletop experiments when we apply localized sources on such materials and measure their responses. [ABSTRACT FROM AUTHOR]

The concept of spacetime loses its usual interpretation at the essential singularity of a black hole. In consequence, all laws of physics must fail at this classical singularity. This unphysical behavior of spacetime at the singularity originates from general relativity. In order to have a consistent description of spacetime, this singularity must disappear in a quantum mechanical description of spacetime which is expected to be given by a quantum theory of gravity. In this paper, we therefore attempt to describe the quantum nature of spacetime in the vicinity of the (classical) singularity of a black hole. We take the Kantowsi–Sachs representation for the interior spacetime of a black hole and include inevitable vacuum fluctuations of matter field in the Klein–Gordon representation. Hence we obtain the Wheeler–DeWitt equation for the black hole interior and solve this equation exactly yielding a general expression for the interior wave function of the black hole. Admissible wave functions consistent with the DeWitt boundary condition implies that the Hilbert space has three nonoverlapping sectors distinguished by the relative character of the eigenvalues. Regular quantum black holes with admissible and well-behaved wave function having no singularity can exist only in two of those sectors. However, the remaining sector does not contain any regular quantum black hole. [ABSTRACT FROM AUTHOR]

We construct the generalized β and (q, t)-deformed partition functions through W representations, where the expansions are respectively with respect to the generalized Jack and Macdonald polynomials labeled by N-tuple of Young diagrams. We find that there are the profound interrelations between our deformed partition functions and the 4d and 5d Nekrasov partition functions. Since the corresponding Nekrasov partition functions can be given by vertex operators, the remarkable connection between our β and (q, t)-deformed W-operators and vertex operators is revealed in this paper. In addition, we investigate the higher Hamiltonians for the generalized Jack and Macdonald polynomials. [ABSTRACT FROM AUTHOR]