arXiv subjects

Qihong Huang

Publications and source records attributed to Qihong Huang.

At least 19 recordsLinked to original sources

arXiv2026

Observational constraints on fractional holographic dark energy in the light of DESI DR2

Based on the fractional entropy from fractional quantum mechanics, fractional holographic dark energy (FHDE) has been proposed with the Hubble horizon as the IR cutoff (FHDEH). We extend this framework by adopting the future event horizon and the particle horizon as the IR cutoff, proposing the FHDEF and FHDEP models. Using the SN+OHD+DESI DR2 dataset to constrain these models, we find that all three models provide a marginally lower $χ^{2}_{min}$ compared to $Λ$CDM but without significant preference according to AIC and BIC. When CMB distance priors are included, the FHDEH and FHDEP models are strongly ruled out. We further analyze the cosmological evolution for these models, and find that only the FHDEF model predicts nearly identical evolutions of $Ω_{m}$ and $Ω_{de}$ to those of the $Λ$CDM model across cosmic history, but its deceleration parameter $q$ deviate from the $Λ$CDM model in the future, indicating richer late time dynamics beyond the standard $Λ$CDM cosmology.

gr-qc↗

arXiv2026

Universal thermodynamic topological classes of the charged dRGT black string

In this study, we explore universal thermodynamic topological classes of charged dRGT black string within both the canonical ensemble and grand canonical ensemble frameworks, and further analyze its asymptotic behavior under limiting parameter regimes. We demonstrate that, while the outermost large black string branch remains thermodynamically stable in both ensembles, the innermost small black string branch exhibits distinctly different stability properties: it is stable in the canonical ensemble but becomes thermodynamically unstable in the grand canonical ensemble, corresponding to the $W^{1+}$ and $W^{0-}$ topological categories, respectively. Furthermore, the local thermodynamic stability of the charged dRGT black string is investigated through the behavior of the heat capacity. These findings demonstrate that the selection of thermodynamic ensemble has a significant influence on the thermodynamic configuration of the charged dRGT black string. In the limit where gravitational effects are neglected, the charge contribution does not modify the underlying topological classification. This implies that the coupling between dRGT massive gravity and the electromagnetic sector is essential for the emergence of nontrivial thermodynamic topology. These results contribute to a deeper understanding of the black string thermodynamics and provide a novel theoretical basis for exploring the basic properties of quantum gravity.

gr-qc↗

arXiv2026

Observational Constraints and Cosmological Dynamics of Interacting Fractional Holographic Dark Energy in Light of DESI DR2

Based on the fractional entropy originating from fractional quantum mechanics, the fractional holographic dark energy (FHDE) model has been proposed. In this paper, we consider an interaction between the pressureless matter and FHDE and analyze three different interacting FHDE models. Combining the latest observational data including SNIa, OHD, BAO, and CMB, we estimate the model parameters and find that the interaction forms $Q=γH ρ_{de}$ and $Q=βH ρ_{m}+γH ρ_{de}$ show some preference from the observational data. Using phase space analysis, we further find that only interacting FHDE model with $Q=βH ρ_{m}+γH ρ_{de}$ can describe the full evolutionary history of the universe. The statefinder diagnostic pair reveals that this model deviates from the $Λ$CDM model but converges to the $Λ$CDM fixed point and the de Sitter expansion fixed point in the future. Finally, we analyze the evolution of cosmological parameters and demonstrate that this model can drive the late time acceleration of the universe.

physics.gen-ph↗

arXiv2026

Holographic inflation and slow-roll inflation within Rényi entropic framework in the light of ACT DR6

Based on the Rényi entropy, Rényi holographic dark energy has been proposed to explain the current accelerated expansion of the universe. In this paper, we analyze holographic inflation and slow-roll inflation within the framework of Rényi holographic dark energy (RHDE) using ACT DR6. Our results show that holographic inflation is ruled out by the data, while slow-roll inflation with power-law potentials for $n=\frac{1}{2}$ and $n=\frac{1}{3}$ is viable for a suitable choice of $N$ and $C$. We also analyze the inflationary attractor and confirm its existence. In addition, we compute the primordial power spectrum and find it falls well within the observational bounds. Thus, slow-roll inflation is favored in RHDE, but holographic inflation is not.

gr-qc↗

arXiv2026

Nearly universal CMB TT spectrum from pre-inflationary dynamics in a closed universe: KICI scenario, bouncing universe, and emergent universe

We utilize the phase space analysis method to study the early evolution of the spatially closed universe and find that there exists an attractor denoting the de Sitter expansion phase, and that the universe has three distinct evolutionary paths, which correspond to the kinetic initial conditions for inflation (KICI) scenario, bouncing universe, and emergent universe. Based on the results of the phase space analysis, we calculate the primordial power spectrum and CMB TT spectrum for these models. We find that, for these models, the primordial power spectrum and CMB TT spectrum are suppressed at large scales. The suppression originates from the pre-inflationary dynamics, while the common suppression trend is a consequence of the positive spatial curvature shared by all three models. The oscillation amplitude, in contrast, is determined by the details of the transition, with a smoother transition yielding a smaller amplitude. Moreover, the CMB TT spectra for these models overlap completely, indicating that these models are indistinguishable via their CMB TT spectra, and that the suppression and the detailed shape of the CMB TT spectrum are independent of the specific pre-inflationary dynamics or the presence of a transition stage in a closed universe.

gr-qc↗

arXiv2025

Novel topological subclass in Hourava-Lifshitz black holes

This work explores the universal classification of thermodynamic topology for charged static black holes within the $z=3$ Hourava-Lifshitz gravity theory, considering both canonical and grand canonical ensembles. We introduce a new topological subclass, denoted as $\ddot{W}^{1-}$. This finding expands the existing topological classification, going beyond the five previously defined classes and their respective subclasses. The $\ddot{W}^{1-}$ subclass presents a distinct and previously unobserved stability profile: In the low-temperature regime, an unstable small black hole appears in the phase space, whereas, while in the high temperature regime, two unstable small black holes exist together with a stable large black hole. Our study underscores the dependence of charged black hole stability on the selection of the ensemble. These results contribute to refining and expanding the topological framework in black hole thermodynamics, providing key perspectives on the underlying nature of black holes and gravity.

gr-qc↗

arXiv2025

Agegraphic dark energy from entropy of the anti-de Sitter black hole

In this paper, we analyze the agegraphic dark energy from the entropy of the anti-de Sitter black hole using the age of the universe as the IR cutoff. We constrain its parameter with the Pantheon+ Type Ia supernova sample and observational Hubble parameter data, finding that the Akaike Information Criterion cannot effectively distinguish this model from the standard $Λ$CDM model. The present value of Hubble constant $H_{0}$ and the model parameter $b^{2}$ are constrained to $H_{0}=67.7 \pm 1.8$ and $b^{2}=0.303^{+0.019}_{-0.024}$. This model realizes the whole evolution of the universe, including the late-time accelerated expansion. Although it asymptotically approaches the standard $Λ$CDM model in the future, statefinder analysis shows that late-time deviations allow the two models to be distinguished.

gr-qc↗

arXiv2025

Constant-roll inflation and primordial black holes within Barrow entropic framework

In this paper, starting from the modified Einstein field equations, we derive the modified scalar spectral index $n_{s}$ and the modified tensor-to-scalar ratio $r$ in Barrow entropy model, calculate their values for the power-law, periodic, and hilltop potential models, constrain the model parameter $δ$ and the potential parameter using Planck 2018 data, and find that increasing $δ$ causes a significant decrease in $r$. Then, we calculate the primordial curvature perturbation power spectra, primordial black hole (PBH) abundance, and scalar induced gravitational waves (SIGWs) for these models, finding PBH mass of approximately $10^{-12} M_{\odot}$, PBH abundance nearly $0.98$, and the peak frequencies of SIGWs on the order $10^{-3} \mathrm{Hz}$, indicating that these models not only generate sufficient PBHs which can contribute one-third of the dark matter content but could also be detected by next-generation missions such as LISA, Taiji, and TianQin. Subsequently, we analyze the evolution of PBHs and find that when the effective equation of state parameter evolves from $1/3$ to $-1/3$, the accretion mass increases to approximately $10^{2}M_{i}$, while the temperature of the PBHs decreases from $10^{4}K$ to $10^{2}K$, suggesting that PBHs exist and are detectable today.

gr-qc↗

arXiv2025

Evolution of the early universe in Einstein-Cartan theory

Einstein--Cartan theory is a generalization of general relativity that introduces spacetime torsion. In this paper, we perform phase space analysis to investigate the evolution of the early universe in Einstein--Cartan theory. By studying the stability of critical points in the dynamical system, we find that there exist two stable critical points which represent an Einstein static solution and an expanding solution, respectively. After analyzing the phase diagram of the dynamical system, we find that the early universe may exhibit an Einstein static state, an oscillating state, or a bouncing state. By assuming the equation of state $ω$ can decrease over time $t$, the universe can depart from the initial Einstein static state, oscillating state, or bouncing state and then evolve into an inflationary phase. Then, we analyze four different inflationary evolution cases in Einstein--Cartan theory and find that a time-variable equation of state $ω$ cannot yield values of $n_{s}$ and $r$ consistent with observations, while a time-invariant equation of state $ω$ is supported by the Planck 2018 results. Thus, in Einstein--Cartan theory, the universe likely originates from a bouncing state rather than an Einstein static state or an oscillating state.

gr-qc↗

arXiv2025

Holographic inflation and holographic dark energy from entropy of the anti-de Sitter black hole

Based on the entropy of anti-de Sitter black hole, a new holographic dark energy model has been proposed. When the Hubble horizon and particle horizon are chosen as the IR cutoff, the late-time accelerated expansion of universe is realized. In this paper, we consider the Hubble horizon as the IR cutoff to investigate holographic inflation and slow-roll inflation in this model. We find that slow-roll inflation with the chaotic potential $V_{0}ϕ^{n}$ is favored by Planck results for some special cases, such as $n=1/3$ and $n=1/2$, while holographic inflation is not supported by Planck results. Then, we analyze the reheating temperature and the number of reheating e-folds in this model, and we find that the results favor the cases $n=1/3$ and $n=1/2$. Finally, we use the dynamical analysis method, statefinder diagnostic pairs, and the Hubble diagram to analyze this model. Our results indicate that when $b^{2}$ takes a small value, this model cannot be distinguished from the standard $Λ$CDM model and can serve as an alternative to it.

gr-qc↗

arXiv2024

Three-dimensional solitons supported by the spin-orbit coupling and Rydberg-Rydberg interactions in PT-symmetric potentials

Excited states (ESs) of two- and three-dimensional (2D and 3D) solitons of the semivortex (SV) and mixed-mode (MM) types, supported by the interplay of the spin-orbit coupling (SOC) and local nonlinearity in binary Bose-Einstein condensates, are unstable, on the contrary to the stability of the SV and MM solitons in their fundamental states. We propose a stabilization strategy for these states in 3D, combining SOC and long-range Rydberg-Rydberg interactions (RRI), in the presence of a spatially-periodic potential, that may include a parity-time (PT)-symmetric component. ESs of the SV solitons, which carry integer vorticities S and S+1 in their two components, exhibit robustness up to S= 4. ESs of MM solitons feature an interwoven necklace-like structure, with the components carrying opposite fractional values of the orbital angular momentum. Regions of the effective stability of the 3D solitons of the SV and MM types (both fundamental ones and ESs), are identified as functions of the imaginary component of the PT-symmetric potential and strengths of the SOC and RRI terms.

cond-mat.quant-gas↗

arXiv2023

Joint Constraints on the Hubble Constant, Spatial Curvature, and Sound Horizon from the Late-time Universe with Cosmography

In this paper, using the latest Pantheon+ sample of Type Ia supernovae (SNe Ia), Baryon Acoustic Oscillation (BAO) measurements, and observational Hubble data (OHD), we carry out a joint constraint on the Hubble constant $H_0$, the spatial curvature $Ω_{\rm K}$, and the sound horizon at the end of drag epoch $r_{\rm d}$. To be model-independent, four cosmography models, i.e., the Taylor series in terms of redshift $y_1=z/(1+z)$, $y_2=\arctan(z)$, $y_3=\ln(1+z)$, and the Padé approximants, are used without the assumption of flat Universe. The results show that the $H_0$ is anti-correlated with $Ω_{\rm K}$ and $r_{\rm d}$, indicating smaller $Ω_{\rm K}$ or $r_{\rm d}$ would be helpful in alleviating the Hubble tension. And the values of $H_0$ and $r_{\rm d}$ are consistent with the estimate derived from the Planck Cosmic Microwave Background (CMB) data based on the flat $Λ$CDM model, but $H_0$ is in 2.3$\sim$3.0$σ$ tension with that obtained by \cite{Riess2022} in all these cosmographic approaches. Meanwhile, a flat Universe is preferred by the present observations under all approximations except the third order of $y_1$ and $y_2$ of the Taylor series. Furthermore, according to the values of the Bayesian evidence, we found that the flat $Λ$CDM remains to be the most favored model by the joint datasets, and the Padé approximant of order (2,2), the third order of $y_3$ and $y_1$ are the top three cosmographic expansions that fit the datasets best, while the Taylor series in terms of $y_2$ are essentially ruled out.

astro-ph.CO↗

arXiv2023

CMB power spectrum for emergent scenario and slow expansion in scalar-tensor theory of gravity

We analyze the stability of the Einstein static universe in scalar-tensor theory of gravity, and find it can be stable against both scalar and tensor perturbations under certain conditions. By assuming the emergent scenario originating from an Einstein static state, followed by an instantaneous transition to an inflationary phase, we study and obtain the analytical approximations of the primordial power spectrum for the emergent scenario. Then, we plot the primordial power spectrum and CMB TT-spectrum of the emergent scenario and the slow expansion scenario. These figures show that both of these spectra for the slow expansion scenario are the same as that for $Λ$CDM, and the spectra of the emergent scenario are lower than that for $Λ$CDM at large scales.

gr-qc↗

arXiv2023

CMB power spectrum in the emergent universe with k-essence

The emergent universe provides a possible method to avoid the big bang singularity by considering that the universe stems from an stable Einstein static universe rather than the singularity. Since the Einstein static universe exists before inflation, it may leave some relics in the CMB power spectrum. In this paper, we analyze the stability condition for the Einstein static universe in general relativity with k-essence against both the scalar and tensor perturbations. And we find the emergent universe can be successfully realized by constructing a scalar potential and an equation of state parameter. Solving the curved Mukhanov-Sasaki equation, we obtain the analytical approximation for the primordial power spectrum, and then depict the TT-spectrum of the emergent universe. The results show that both the primordial power spectrum and CMB TT-spectrum are suppressed on large scales.

gr-qc↗

arXiv2023

Strong gravitational lensing of rotating regular black holes in non-minimally coupled Einstein-Yang-Mills theory

The strong gravitational lensing of a regular and rotating magnetic black hole in non-minimally coupled Einstein-Yang-Mills theory is studied. We find that, with the increase of any characteristic parameters of this black hole, such as the rotating parameter, magnetic charge and EYM parameter, the angular image position and relative magnification decrease while deflection angle and image separation increase. The results will degenerate to that of the Kerr case, R-N case with magnetic charge and Schwarzschild case when we take some specific values for the black hole parameters. The results also show that, due to the small influence of magnetic charge and Einstein-Yang-Mills parameters, it is difficult for current astronomical instruments to tell this black hole apart from a General Relativity one.

gr-qc↗

arXiv2022

Model-independent test for the cosmic distance duality relation with Pantheon and eBOSS DR16 quasar sample

In this paper, we carry out a new model-independent cosmological test for the cosmic distance duality relation~(CDDR) by combining the latest five baryon acoustic oscillations (BAO) measurements and the Pantheon type Ia supernova (SNIa) sample. Particularly, the BAO measurement from extended Baryon Oscillation Spectroscopic Survey~(eBOSS) data release~(DR) 16 quasar sample at effective redshift $z=1.48$ is used, and two methods, i.e. a compressed form of Pantheon sample and the Artificial Neural Network~(ANN) combined with the binning SNIa method, are applied to overcome the redshift-matching problem. Our results suggest that the CDDR is compatible with the observations, and the high-redshift BAO and SNIa data can effectively strengthen the constraints on the violation parameters of CDDR with the confidence interval decreasing by more than 20 percent. In addition, we find that the compressed form of observational data can provide a more rigorous constraint on the CDDR, and thus can be generalized to the applications of other actual observational data with limited sample size in the test for CDDR.

astro-ph.CO↗

arXiv2022

Analytical approximations for primordial power spectra in a spatially closed emergent universe

The emergent universe scenario was proposed to solve the big bang singularity by suggesting that the universe originates from an Einstein static state and then evolves into a subsequently inflationary era. Thus, to find the relic of the existence of the Einstein static state becomes a crucial work. In this paper, we derive analytical approximation of the primordial power spectra and analyze the CMB TT-spectra for the spatially closed emergent universe. After analyzing the CMB TT-spectrum of the emergent universe scenario, we find that both the CMB TT-spectra produced by the Einstein static state followed by the ultraslow-roll inflationary epoch (method I) and by a special evolution of the scale factor in the emergent scenario as $a=a_{0}+A e^{H_{0}t}$(method II) are suppressed at $l<30$, and their spectra are nearly identical. Additionally, by comparing the spectra of the emergent universe scenario with the ones of the ultraslow-roll inflationary model in the closed universe, we find that the CMB TT-spectrum of the emergent universe is similar to the one of the inflationary model with the special case $η_t = η_{max}$.

gr-qc↗

arXiv2022

Emergent scenario in mimetic gravity

The emergent scenario provides a possible way to avoid the big bang singularity by assuming that the universe originates from an Einstein static state. Therefore, an Einstein static universe stable under perturbations is crucial to a successful implementation of the emergent mechanism. In this paper, we analyze the stability of the Einstein static universe against the scalar perturbations in the mimetic theory and find that stable Einstein static solutions exist under certain conditions in this theory. In the original mimetic gravity, the Einstein static universe is unstable. Then, we find that the universe can naturally exit from the initial static state, evolve into an inflationary era and then exit from the inflationary era. Thus, the emergent scenario can be used to resolve the big bang singularity in the mimetic theory.

gr-qc↗