arXiv subjects

Yupeng Yang

Publications and source records attributed to Yupeng Yang.

At least 19 recordsLinked to original sources

arXiv2026

Constraining spinning primordial black holes with interstellar dust heating

Primordial black holes (PBHs) are a well-motivated dark matter candidate, and their cosmic abundance is constrained by a variety of observational probes. PBHs in the mass range $10^{15}\,\text{g}\,{-}\,10^{17}\,\text{g}$ are evaporating today via Hawking radiation, a process that can heat interstellar dust and modify its thermal emission. Recent studies have used this effect to place constraints on the abundance of non-spinning PBHs. We extend this approach by investigating the influence of PBH spin on dust-heating constraints. Furthermore, we account for secondary photons that originate not only from the decay of gauge bosons but also from the decay of hadrons produced via the fragmentation of primary quarks and gluons emitted through Hawking radiation. By comparing the dust heating rate induced by spinning PBHs with the maximum cooling rate of dust, considering both silicate and graphite grains, we derive new upper limits on the fraction of dark matter in the form of PBHs, $f_{\rm PBH}$. Our results show that the constraints depend on both PBH mass and spin. Smaller PBHs with higher spin yield stronger limits. For example, in the cases we investigated, the strongest constraint is $f_{\rm PBH} \sim 1.5 \times 10^{-4}$ for $M_{\rm PBH} = 10^{15}{\rm g}$ and spin parameter $a_{*} = 0.9999$. Although these limits are less stringent than existing constraints in the same mass range, they provide a distinct and complementary approach to constraining the abundance of PBHs.

astro-ph.CO↗

arXiv2026

Constraints on redshift-evolving Hubble constant models with early- and late-time diagnostics

We systematically investigate four cosmological models within a parameterized framework that allows for a redshift dependence of $H_0$: three phenomenological models ($\alpha\Lambda$CDM, $\alpha w$CDM, and $\alpha w_0w_a$CDM), and the $J$CDM model motivated by big bang quantum cosmology. Using cosmic microwave background (CMB) data, baryon acoustic oscillations (BAO), cosmic chronometer (CC) measurements of the Hubble parameter, and three Type Ia supernova samples (PantheonPlus, DESY5, and Union3), we perform Markov chain Monte Carlo (MCMC) analyses to obtain posterior distributions of the model parameters. We also perform separate analyses using early-time and late-time data to assess how each observational epoch affects the model constraints. For the three phenomenological models, the parameter $\alpha$ describing the redshift evolution of $H_0$ is consistent with zero within $2\sigma$. The Hubble constant inferred from the $\alpha\Lambda$CDM model is consistent with CMB results, while the $J$CDM model yields a larger Hubble constant but is strongly disfavored by model comparison criteria. Using the Akaike Information Criterion (AIC) and the Bayesian Information Criterion (BIC) for model comparison, we find that the standard $\Lambda$CDM model remains the most favored by the data. Among the four models, the $\alpha w_0w_a$CDM model shows a marginal AIC advantage ($\rm \Delta AIC \sim$ -2 to -13). However, this preference does not translate into a reduction of the Hubble tension, which is consistent with existing studies supporting dynamical dark energy. Moreover, none of the models can simultaneously satisfy both the early- and late-time constraints, and the combined datasets alone are insufficient to conclusively determine whether these parametrizations can resolve the tension.

physics.gen-ph↗

arXiv2026

Refining primordial black hole dark matter constraints with dust heating: the role of spin and halo profile dependence

Primordial black holes (PBHs) are compelling dark matter candidates. PBHs with masses between $10^{15}$ and $10^{18}\,\mathrm{g}$ can heat interstellar dust via Hawking radiation. Previous studies of this dust heating mechanism mostly neglected PBH spin and adopted a single dark matter halo profile. In this work, we incorporate PBH spin, which substantially enhances the emitted radiation flux, and systematically investigate the dependence of constraints on the dark matter density distribution by considering five different halo models. We compute the complete photon spectra, including both primary and secondary emissions. Our results show that, for a fixed profile and mass function, larger spin parameters yield stronger constraints on the PBH fraction $f_{\mathrm{PBH}}$. Among the halo models, the Isothermal profile gives the most stringent limits, followed by Einasto, then NFW and Moore, while the Burkert profile yields the weakest constraints. For silicate grains, which cool less efficiently than graphite, the upper limits reach $\mathcal{O}(10^{-4})$ for high spin cases. We consider both monochromatic and lognormal mass functions, and find consistent trends between them. For the lognormal case, larger values of the width $\sigma$ lead to a broader mass range being excluded, in particular ruling out massive PBHs as the sole dark matter component. Our bounds are generally weaker than other existing limits, but they provide a complementary and independent constraint.

astro-ph.CO↗

arXiv2026

Constraining primordial black holes and primordial curvature power spectrum with extragalactic muon neutrino

We investigate a mixed dark matter scenario comprising weakly interacting massive particles (WIMPs) and primordial black holes (PBHs). After PBH formation, WIMPs can accrete onto them, forming ultracompact minihalos (UCMHs). The resulting WIMP number density within UCMHs is significantly enhanced compared to classical dark matter halo models, leading to a higher WIMP annihilation rate. Previous studies have focused mainly on the associated gamma-ray flux, we investigate the extragalactic neutrino flux from such annihilation. Considering the annihilation channels $\mu^{+}\mu^{-}$, $\tau^{+}\tau^{-}$, and $\nu_{\mu}\bar{\nu}_{\mu}$, we analyze two classes of neutrino events: upward and contained events. By requiring the neutrino flux from WIMP annihilation around PBHs does not exceed the atmospheric neutrino background, we derive upper limits on the fraction of dark matter in PBHs ($f_{\rm PBH}$) for a one-year exposure of the IceCube experiment. These limits depend on the annihilation channel, the masses of the WIMP and PBH, and the neutrino event type. The strongest constraints come from the $\nu_{\mu}\bar{\nu}_{\mu}$ channel, yielding $f_{\rm PBH} \sim 10^{-4}$ ($4\times 10^{-5}$) for contained (upward) events with $m_{\chi}=10^{3}$ GeV and $M_{\rm PBH}=10^{3} M_{\odot}$. Based on these bounds on PBHs, we further derive upper limits on the primordial curvature power spectrum $\mathcal{P}_{\mathcal{R}}$. From our strongest constraint, we obtain $\mathcal{P}_{\mathcal{R}} \sim 10^{-1.65}$ at the scale $k\sim 3\times 10^{12}~\mathrm{Mpc^{-1}}$.

astro-ph.CO↗

arXiv2026

Cosmological Constraints on the DGP Model in light of DESI DR2 2025 Data

We present updated constraints on both flat and non-flat Dvali-Gabadadze-Porrati (DGP) cosmological models using the latest baryon acoustic oscillation (BAO) measurements from the Dark Energy Spectroscopic Instrument Data Release 2 (DESI DR2), in combination with cosmic chronometer (CC), Type Ia supernova (SNIa), and cosmic microwave background (CMB) distance priors. For the non-flat DGP model, we obtain $H_0 = 64.05 \pm 0.27\, \rm{kms^{-1}Mpc^{-1}}$, $\Omega_m = 0.3264 \pm 0.0043$, and $\Omega_k = 0.0088 \pm 0.0016$, corresponding to a transition redshift $z_t \sim 0.41$. For the flat case, the constraints are $H_0 = 63.28 \pm 0.25\, \rm{kms^{-1}Mpc^{-1}}$ and $\Omega_m = 0.3303 \pm 0.0036$. In both scenarios, the inferred Hubble constant is significantly lower than the Planck $\mathrm{\Lambda}$CDM value, indicating that the DGP framework does not alleviate the Hubble tension. Current observations strongly disfavor the DGP framework, primarily due to its inability to simultaneously accommodate DESI BAO and CMB constraints.By incorporating the latest high-precision DESI observations within a unified analysis framework, this work provides updated and more stringent limits on the DGP scenario, offering a consolidated assessment of its viability in the context of current cosmological data.

astro-ph.CO↗

arXiv2026

Spatio-Temporal Reconnection for Multi-Robot Networks using Adaptive Prescribed-Time CBFs

In multi-robot systems, maintaining persistent communication graph connectivity is often overly restrictive, especially when robots have limited communication ranges but operate in large environments. Instead, allowing robots to temporarily disconnect and later reconnect is often more desirable for efficient task execution while still ensuring timely information sharing across the team. In this paper, we propose an adaptive prescribed-time control barrier function (adaptive PT-CBF) framework that enables robots to temporarily disconnect and re-enter the communication range within an adjustable and feasible prescribed time. Moreover, we introduce a reconnection triggering mechanism that jointly considers task execution and reconnection urgency, thereby providing a principled way to decide when reconnection should occur. Theoretical analysis justifies convergence to the satisfying reconnection within a prescribed finite time. Experimental results validate the performance of our proposed adaptive PT-CBF with improved task efficiency and satisfying reconnections.

cs.RO↗

arXiv2026

Geometry-Aware Control Barrier Functions for Collision Avoidance via Bernstein Polynomial Approximations

Safe navigation often relies on well-defined conditions based on the shape of robots and obstacles, and can be challenging when they have irregular geometries. While Control Barrier Functions (CBFs) offer an efficient mechanism to enforce safe set forward invariance, common shape surrogates (e.g., spheres or super-ellipsoids) either are overly conservative in unstructured scenes or require many local primitives, which inflates constraint counts and degrades real-time performance. In this paper, we introduce a novel geometry-aware Control Barrier Function (CBF) based on Bernstein-Polynomial Signed Distance Fields (BP-SDFs). It provides a unified way to represent the obstacles and robots, so as to represent the barrier function with a unified minimum distance. Benefiting from the differentiability of the Bernstein polynomials, one can easily enforce the control constraints in a closed loop. We validate the method's efficiency and performance to guarantee safety in single-robot navigation and heterogeneous multi-robot collision avoidance via simulations under different environments.

cs.RO↗

arXiv2026

Cosmological constraints on the big bang quantum cosmology model

The big bang quantum cosmology model introduces the trace $J$ of the Schouten tensor as a form of dynamic dark energy. Together with cold dark matter, these components form the so-called $J$CDM cosmology model, proposed by M.H.P.M. van Putten (J. High Energy Astrophys., 45, 2025, 194), which offers a potential resolution to the Hubble tension. We derive the constraints on the $J$CDM cosmology model, utilizing early- and late-time cosmological data including cosmic microwave background (CMB), baryon acoustic oscillations (BAO) released by the Dark Energy Spectroscopic Instrument (DESI), cosmic chronometers (CC), and type Ia supernovae (SNIa). For a flat universe, the $J$CDM model yields $ H_0 = 66.95 \pm 0.51 \, \rm{km~s^{-1}~Mpc^{-1}} $ and $ \Omega_m = 0.3419 \pm 0.0065 $, results that are consistent with early-universe observations but exhibit a higher $ \Omega_m $ compared to the $\Lambda$CDM model. In the case of a non-flat universe, $J$CDM favors a slightly curved geometry with $ \Omega_k = 0.0154 \pm 0.0027 $, leading to $ H_0 = 69.13 \pm 0.56 \, \rm {km~s^{-1}~Mpc^{-1}} $ and $ \Omega_m = 0.3477 \pm 0.0074 $. The increase in $ H_0 $ in the non-flat scenario suggests a geometric degeneracy between spatial curvature and $ H_0 $. We also investigate the internal inconsistencies present in DESI data and evaluate their impacts on cosmological parameter constraints. Our analysis shows that while the $J$CDM model, which is constructed from first principles without free parameters beyond those of $\Lambda$CDM, agrees excellently with late-time cosmology, it struggles to simultaneously match early-universe observations in a fully self-consistent manner.

astro-ph.CO↗

arXiv2026

Redshift evolution of the Hubble constant: Constraints and new insights from an interacting dark energy model

We develop a modified interacting dark energy (IDE) model to study the redshift evolution of the Hubble constant ($H_0$), in light of the Hubble tension. In this framework, the energy exchange between dark energy and dark matter induces a redshift dependence of $H_0$. We evaluate the model against a comprehensive suite of observations, including baryon acoustic oscillations (BAO) from DESI DR2 and SDSS, cosmic chronometers, type Ia supernovae from the Pantheon sample, and Planck CMB distance priors. Analysis of late-Universe data yields $\alpha = 0.0107^{+0.0032}_{-0.011}$, with the best-fit value on the order of $10^{-2}$, revealing a decreasing trend of $H_0$ with redshift. This supports a power-law evolution beyond $\Lambda$CDM. Incorporating CMB data further tightens the constraint to the order of $10^{-5}$, which we attribute to the suppression of dark-sector interactions at high redshifts, a consequence of the strong baryon--photon coupling. These results indicate that the IDE framework provides a theoretically consistent and observationally viable mechanism for describing the redshift evolution of $H_0$, offering a promising avenue toward alleviating the Hubble tension.

astro-ph.CO↗

arXiv2025

Constraining deviations from $\Lambda$CDM in the Hubble expansion rate

The $\Lambda$CDM cosmolgical model has long been regarded as highly successful in accurately describing a wide range of astronomical observations. However, numerous observational findings have also provided hints of discrepancies from the predictions of the $\Lambda$CDM framework. We explore a phenomenological model that quantifies the deviation of the Hubble expansion rate from the standard scenario, which is expressed as $H^{2}(z) = H^{2}_{\rm \Lambda CDM}(\Omega_m, z)[1+\delta(z)]$. We consider three distinct forms for the deviation parameter $\delta(z)$: in model I, $\delta(z)=\delta_c$; in model II, $\delta(z)=\delta_{c}z/(1+z)$, and in model III, $\delta(z)=\delta_{c}{\rm ln}(1+z)$. Here, $\delta_c$ represents a constant value. We utilize a comprehensive set of observational data to constrain the models. Our results show that for most combined datasets, $\delta_c$ tends to take on negative values for models I and II, while consistently taking positive values in model III. Furthermore, we find that both models I and II remain consistent with the standard $\Lambda$CDM model across all datasets examined. In contrast, model III exhibits a significant deviation from the $\Lambda$CDM model, exceeding $2\sigma$ for the full combined datastes. The AIC indicates that models I and II are consistent with the $\Lambda$CDM model, whereas model III is preferred over the standard $\Lambda$CDM model, with the $\Lambda$CDM model being disfavored for the combined datasets DESI BAO + CMB + CC + DESY5. These results suggest that the Hubble expansion rate likely deviates from the standard $\Lambda$CDM prediction.

astro-ph.CO↗

arXiv2025

Cosmological abundance of primordial black holes in mixed dark matter scenarios incorporating Kaluza-Klein dark matter

The lightest Kaluza-Klein (KK) dark matter particles and primordial black holes (PBHs) emerge as plausible candidates for dark matter. In scenarios where dark matter is a mix of KK particles and PBHs, PBHs can attract surrounding KK dark matter particles post-formation, leading to the creation of ultracompact dark matter halos (UCMHs). The distribution of KK dark matter particles within UCMHs tends to be steeper than in classical dark matter halo structures, such as the Navarro-Frenk-White model. Consequently, the annihilation rate of KK dark matter particles in UCMHs is significant. The high-energy photons resulting from the annihilation of KK particles in UCMHs contribute to the extragalactic gamma-ray background (EGB). Leveraging data from the $\mathtt{Fermi\text{-}LAT}$ experiment, we have derived, for the first time, upper limits on the cosmological abundance of PBHs in the context of KK dark matter annihilation. For a KK dark matter mass range of $500\le m_{\rm B^{(1)}}\le 1500$ GeV, which aligns with the observed present abundance of dark matter, the conservative limits on the fraction of dark matter in PBHs, for massive PBHs with $M_{\rm PBH}\gtrsim 10^{-11}M_{\odot}$, are $f_{\rm PBH} \lesssim 2\times 10^{-5}$.

astro-ph.CO↗

arXiv2025

New cosmological constraints on the evolution of dark matter energy density

We constrain the evolution of dark matter energy density over time, specifically focusing on deviation from the standard model represented by the equation $ρ_{m}\propto(1+z)^{3-\varepsilon}$, where $\varepsilon$ is a constant parameter. Utilizing a diverse array of observational datasets, including baryon acoustic oscillations (BAO) data from the first release of the Dark Energy Spectroscopic Instrument (DESI), distance priors derived from cosmic microwave background (CMB) observations by the Planck satellite, Hubble rate data obtained through the cosmic chronometers (CC) method, type Ia supernova (SNIa) data from the Panthon sample, and the data from the redshift space distortion (RSD) measurements ($fσ_8$), we derive stringent constraints on the deviation parameter. We find that for the model under consideration, the deviation parameter is constrained to be $\varepsilon = -0.0073^{+0.0029}_{-0.0033}$, indicating a deviation of approximately $2.4σ$ from the scenario where dark matter and vacuum dark energy do not interact. When compared with previous studies and alternative analyses, our findings provide corroborative evidence for an interaction between dark matter and vacuum dark energy, particularly in light of the release of BAO data from DESI.

astro-ph.CO↗

arXiv2025

Courteous MPC for Autonomous Driving with CBF-inspired Risk Assessment

With more autonomous vehicles (AVs) sharing roadways with human-driven vehicles (HVs), ensuring safe and courteous maneuvers that respect HVs' behavior becomes increasingly important. To promote both safety and courtesy in AV's behavior, an extension of Control Barrier Functions (CBFs)-inspired risk evaluation framework is proposed in this paper by considering both noisy observed positions and velocities of surrounding vehicles. The perceived risk by the ego vehicle can be visualized as a risk map that reflects the understanding of the surrounding environment and thus shows the potential for facilitating safe and courteous driving. By incorporating the risk evaluation framework into the Model Predictive Control (MPC) scheme, we propose a Courteous MPC for ego AV to generate courteous behaviors that 1) reduce the overall risk imposed on other vehicles and 2) respect the hard safety constraints and the original objective for efficiency. We demonstrate the performance of the proposed Courteous MPC via theoretical analysis and simulation experiments.

cs.RO↗

arXiv2025

Adaptive Deadlock Avoidance for Decentralized Multi-agent Systems via CBF-inspired Risk Measurement

Decentralized safe control plays an important role in multi-agent systems given the scalability and robustness without reliance on a central authority. However, without an explicit global coordinator, the decentralized control methods are often prone to deadlock -- a state where the system reaches equilibrium, causing the robots to stall. In this paper, we propose a generalized decentralized framework that unifies the Control Lyapunov Function (CLF) and Control Barrier Function (CBF) to facilitate efficient task execution and ensure deadlock-free trajectories for the multi-agent systems. As the agents approach the deadlock-related undesirable equilibrium, the framework can detect the equilibrium and drive agents away before that happens. This is achieved by a secondary deadlock resolution design with an auxiliary CBF to prevent the multi-agent systems from converging to the undesirable equilibrium. To avoid dominating effects due to the deadlock resolution over the original task-related controllers, a deadlock indicator function using CBF-inspired risk measurement is proposed and encoded in the unified framework for the agents to adaptively determine when to activate the deadlock resolution. This allows the agents to follow their original control tasks and seamlessly unlock or deactivate deadlock resolution as necessary, effectively improving task efficiency. We demonstrate the effectiveness of the proposed method through theoretical analysis, numerical simulations, and real-world experiments.

eess.SY↗

arXiv2025

Cosmological constraints on two vacuum decay models

We constrain two vacuum decay models ($Λ(t)$CDM, proposed by the authors of~\cite{Brito:2024bhh}) utilizing the baryon acoustic oscillations (BAO) data released by the Dark Energy Spectroscopic Instrument (DESI), distance prior from the cosmic microwave background (CMB) observed by the Planck satellite, Hubble rate data obtained via the cosmic chronometers (CC) method and type Ia supernova (SNIa) data. The interaction terms between dark matter and dark energy are defined as $Q=3\varepsilon Hρ_Λ$ for model I and $3\varepsilon aHρ_Λ$ for model II. We find that the decay parameter is constrained to be $\varepsilon=0.0094^{+0.0037}_{-0.0033}$ for model I and $\varepsilon=0.0119\pm{0.0045}$ for model II, respectively, indicating a potential interaction between dark matter and dark energy at the $2σ$ confidence level. The current Hubble parameter values are estimated to be $H_{0}=70.30\pm{0.67}$ for model I and $H_{0}=70.28\pm{0.64}$ for model II. These values of $H_0$ fall between those derived from the Planck and SH0ES data, suggesting that these two vacuum decay models could provide a potential solution to alleviate the Hubble tension problem.

astro-ph.CO↗

arXiv2024

Constraints on the primordial curvature power spectrum at small scales between $3\times 10^{18}$ and $4.5\times 10^{21}~\rm Mpc^{-1}$

The primordial curvature power spectrum $\mathcal{P}_\mathcal{R}$ has been measured with high precision on large scales $10^{-4}\lesssim k\lesssim 3~\rm Mpc^{-1}$ based on observations of the cosmic microwave background, Lyman-$\alpha$ forest and large scale structure. On small scales $3\lesssim k \lesssim 10^{23}~\rm Mpc^{-1}$, constraints are primarily derived from studies on primordial black holes (PBHs). In particular, for very small scales $10^{17}\lesssim k\lesssim 10^{23}~{\rm Mpc^{-1}}$, current limits come exclusively from investigations of the lightest supersymmetric particles produced by PBH radiation and the stable Planck-mass relics after their evaporation. Recent findings also indicate that the evaporation of light PBHs ($M_{\rm PBH}\lesssim 10^{9}~\rm g$) can modify the expansion rate of the Universe and the baryon-to-photon ratio, thereby affecting the primordial abundance of light nuclei. Moreover, it has been proposed that the ``memory burden'' effect can slow down the mass loss rate of black holes, allowing light PBHs to survive until today. Based on recent theoretical advancements in black hole physics and existing constraints on the initial mass fraction of light PBHs with masses $10^{3}\lesssim M_{\rm PBH}\lesssim 2\times 10^{9}~\rm g$, and especially the recent constraints on memory-burdened PBHs, we derive new and tighter upper limits on $\mathcal{P}_\mathcal{R}$ on small scales $3\times 10^{18}\lesssim k\lesssim 4.5\times 10^{21}~\rm Mpc^{-1}$, a regime that has been underexplored in previous literature. These constraints are derived under the specific assumption that the memory burden effect activates after the PBH loses half of its initial mass and subsequently halts further evaporation, and different assumptions on the memory burden parameters would lead to modified limits.

astro-ph.CO↗

arXiv2024

Integrating Online Learning and Connectivity Maintenance for Communication-Aware Multi-Robot Coordination

This paper proposes a novel data-driven control strategy for maintaining connectivity in networked multi-robot systems. Existing approaches often rely on a pre-determined communication model specifying whether pairwise robots can communicate given their relative distance to guide the connectivity-aware control design, which may not capture real-world communication conditions. To relax that assumption, we present the concept of Data-driven Connectivity Barrier Certificates, which utilize Control Barrier Functions (CBF) and Gaussian Processes (GP) to characterize the admissible control space for pairwise robots based on communication performance observed online. This allows robots to maintain a satisfying level of pairwise communication quality (measured by the received signal strength) while in motion. Then we propose a Data-driven Connectivity Maintenance (DCM) algorithm that combines (1) online learning of the communication signal strength and (2) a bi-level optimization-based control framework for the robot team to enforce global connectivity of the realistic multi-robot communication graph and minimally deviate from their task-related motions. We provide theoretical proofs to justify the properties of our algorithm and demonstrate its effectiveness through simulations with up to 20 robots.

cs.RO↗

arXiv2024

BACKRUNNER: Mitigating Smart Contract Attacks in the Real World

Billions of dollars have been lost due to vulnerabilities in smart contracts. To counteract this, researchers have proposed attack frontrunning protections designed to preempt malicious transactions by inserting "whitehat" transactions ahead of them to protect the assets. In this paper, we demonstrate that existing frontrunning protections have become ineffective in real-world scenarios. Specifically, we collected 158 recent real-world attack transactions and discovered that 141 of them can bypass state-of-the-art frontrunning protections. We systematically analyze these attacks and show how inherent limitations of existing frontrunning techniques hinder them from protecting valuable assets in the real world. We then propose a new approach involving 1) preemptive hijack, and 2) attack backrunning, which circumvent the existing limitations and can help protect assets before and after an attack. Our approach adapts the exploit used in the attack to the same or similar contracts before and after the attack to safeguard the assets. We conceptualize adapting exploits as a program repair problem and apply established techniques to implement our approach into a full-fledged framework, BACKRUNNER. Running on previous attacks in 2023, BACKRUNNER can successfully rescue more than \$410M. In the real world, it has helped rescue over \$11.2M worth of assets in 28 separate incidents within two months.

cs.CR↗