arXiv subjects

Wenshuai Liu

Publications and source records attributed to Wenshuai Liu.

At least 19 recordsLinked to original sources

arXiv2026

Embodied AI in 6G Networks: From Intelligent Connectivity to Physical Intelligence

Embodied artificial intelligence (AI) couples perception and learned decision making to actions that change the physical world. This coupling distinguishes an embodied agent from a conventional connected controller: the agent maintains task state and uncertainty, reasons about the consequences of actions, and adapts from subsequent observations. Wireless networking becomes relevant when perception, inference, or coordination is distributed, but it should not replace local safety control. This article develops a tutorial perception--communication--action (PCA) architecture that exposes task state, action deadlines, uncertainty, agent intent, and safety envelopes to a 6G orchestration plane. It separates capabilities already addressed by 5G and 5G-Advanced from functions that motivate 6G, including task-state interfaces, semantic freshness, predictive digital twins, and safety-aware coordination across agents. A multi-robot simulation study is retained to illustrate joint sensing, communication, and computation control. The results show where network orchestration improves task utility and where local autonomy remains essential.

cs.NI↗

arXiv2026

Giant impact between high-viscosity Theia and low-viscosity proto-Earth: Origin of lunar isotopic crisis

According to the giant impact theory, the Moon was formed by accretion of the debris disk that resulted from the collision between Theia and the proto-Earth. Although this theory accounts for most characteristics of the Earth-Moon system, numerical simulations of impacts between a planetary embryo and the accreting proto-Earth indicate that more than 40 percent of the material in the circum-terrestrial disk generated by such an impact originates from the impactor. This poses a challenge for the giant impact theory in explaining the Moon's Earth-like isotopic composition, a discrepancy known as the lunar isotopic crisis. Since terrestrial planets were melted one or more times during accretionary processes, magma ocean on the surface of a growing planet would appear. Small terrestrial planets with magma ocean cool faster than large ones, resulting that the viscosity of small terrestrial planets is larger than that of large terrestrial planets still covered by magma ocean. Here, it shows that giant impact between a high-viscosity Theia and a low-viscosity proto-Earth could produce a circum-terrestrial debris disk predominantly composed of material from the proto-Earth without violating the angular momentum constraint of modern Earth-Moon system. The theory proposed here may provide a natural way of explaining the lunar isotopic crisis.

astro-ph.EP↗

arXiv2026

Origin of the lunar farside highlands from Earthshine-induced global circulation in lunar magma ocean

The lunar farside highlands, referred to as the lunar farside thicker crust compared with the nearside crust, presents a challenge to the theory of formation and evolution of the Moon. Here, we show that, after the Moon reached synchronous rotation, Earthshine could induce global circulation in lunar magma ocean due to the imposed surface temperature gradient generated by the hot, post-giant impact Earth. The global circulation, generating downwellings on the farside and a deeper return flow on the nearside, results that magmas flow from the nearside to the farside in the shallow magma ocean while the the direction of flow is opposite in the deep magma ocean. Such flow in the shallow magma ocean would transport anorthositic crystals formed in the nearside to the farside. Furthermore, since the lunar farside is cooler than the nearside, crystallization is much more efficient at the farside, resulting that farside magmas transported from the nearside produce anorthositic crystals rapidly. The theory proposed here may provide a natural way of explaining the origin of the lunar farside highlands and the lunar dichotomy.

astro-ph.EP↗

arXiv2026

Origin of the lunar inclination from tidal interaction of multiple-moon system

According to the giant impact theory, the Moon formed through accreting the debris disk produced by a collision between Theia and the proto-Earth, and the predicted lunar orbital inclination relative to the Earth's equatorial plane is about within one degree when Moon formed. However, the current lunar orbital inclination with five degrees relative to the Earth's orbital plane requires the Moon's orbital inclination relative to the Earth's equator to be about ten degrees when traced back to the time of lunar formation. Since two moons are also a natural outcome of simulations of lunar formation from a protolunar disk produced by a giant impact, here we show that, under solar perturbation, gravitational tidal interaction between Earth and its two moons with negligible orbital inclination relative to Earth's equatorial plane could lead to a merger of one moon with Earth, or a merger of the two moons or an ejection of one moon, resulting that the surviving moon's orbital inclination relative to Earth's equator could exceed ten degrees. The theory proposed here may provide a way of explaining the initial large lunar inclination relative to the Earth's equator.

astro-ph.EP↗

arXiv2025

Lightweight posterior construction for gravitational-wave catalogs with the Kolmogorov-Arnold network

Neural density estimation has seen widespread applications in the gravitational-wave (GW) data analysis, which enables real-time parameter estimation for compact binary coalescences and enhances rapid inference for subsequent analysis such as population inference. In this work, we explore the application of using the Kolmogorov-Arnold network (KAN) to construct efficient and interpretable neural density estimators for lightweight posterior construction of GW catalogs. By replacing conventional activation functions with learnable splines, KAN achieves superior interpretability, higher accuracy, and greater parameter efficiency on related scientific tasks. Leveraging this feature, we propose a KAN-based neural density estimator, which ingests megabyte-scale GW posterior samples and compresses them into model weights of tens of kilobytes. Subsequently, analytic expressions requiring only several kilobytes can be further distilled from these neural network weights with minimal accuracy trade-off. In practice, GW posterior samples with fidelity can be regenerated rapidly using the model weights or analytic expressions for subsequent analysis. Our lightweight posterior construction strategy is expected to facilitate user-level data storage and transmission, paving a path for efficient analysis of numerous GW events in the next-generation GW detectors.

gr-qc↗

arXiv2025

Heterogeneous Multi-agent Collaboration in UAV-assisted Mobile Crowdsensing Networks

Unmanned aerial vehicles (UAVs)-assisted mobile crowdsensing (MCS) has emerged as a promising paradigm for data collection. However, challenges such as spectrum scarcity, device heterogeneity, and user mobility hinder efficient coordination of sensing, communication, and computation. To tackle these issues, we propose a joint optimization framework that integrates time slot partition for sensing, communication, and computation phases, resource allocation, and UAV 3D trajectory planning, aiming to maximize the amount of processed sensing data. The problem is formulated as a non-convex stochastic optimization and further modeled as a partially observable Markov decision process (POMDP) that can be solved by multi-agent deep reinforcement learning (MADRL) algorithm. To overcome the limitations of conventional multi-layer perceptron (MLP) networks, we design a novel MADRL algorithm with hybrid actor network. The newly developed method is based on heterogeneous agent proximal policy optimization (HAPPO), empowered by convolutional neural networks (CNN) for feature extraction and Kolmogorov-Arnold networks (KAN) to capture structured state-action dependencies. Extensive numerical results demonstrate that our proposed method achieves significant improvements in the amount of processed sensing data when compared with other benchmarks.

cs.LG↗

arXiv2025

Origin of the lunar isotopic crisis from solidification of a stratified lunar magma ocean

According to the giant impact theory, the Moon formed through accreting the debris disk produced by a collision between Theia and the proto-Earth. The giant impact theory can explain most of the properties of the Earth-Moon system, however, simulations with respect to giant impact between a planetary embryo and the growing proto-Earth show that more than 40 percent of the materials in the circum-terrestrial debris disk produced by the giant impact originates from the impactor. Thus, the giant impact theory has difficulty explaining the Moon's Earth-like isotopic compositions, which is referred to as the lunar isotopic crisis. With the assumption that Theia may have possessed an iron-rich mantle compared with proto-Earth's mantle, here we show that, after the formation of the stratified lunar magma ocean, solidification of the stratified lunar magma ocean would result that the upper solid layer is composed of proto-Earth's mantle and the lower solid layer is made of Theia's mantle, meaning that the Moon's Earth-like isotopic composition is a natural result of the giant impact. The theory proposed here may provide a way of explaining the lunar isotopic crisis.

astro-ph.EP↗

arXiv2025

Origin of the Moon's Earth-like isotopic composition from giant impact on a differential rotating proto-Earth

According to the giant impact theory, the Moon formed by accreting the circum-terrestrial debris disk produced by Theia colliding with the proto-Earth. The giant impact theory can explain most of the properties of the Earth-Moon system, however, simulations of giant impact between a planetary embryo and the growing proto-Earth indicate that the materials in the circum-terrestrial debris disk produced by the impact originate mainly from the impactor. Thus, the giant impact theory has difficulty explaining the Moon's Earth-like isotopic compositions. More materials from the proto-Earth could be delivered to the circum-terrestrial debris disk when a slightly sub-Mars-sized body collides with a fast rotating planet of rigid rotation but the resulting angular momentum is too large compared with that of the current Earth-Moon system. Since planetesimals accreted by the proto-Earth hit the surface of the proto-Earth, enhancing the rotation rate of the surface of the proto-Earth. The surface's fast rotation rate relative to the slow rotation rate of the inner region of the proto-Earth leads to transfer of angular momentum from surface to inner, resulting in the differential rotation. Here, we show that the giant impact of a sub-Mars-sized body on a differential rotating proto-Earth with a fast rotating outer region and a relative slow rotating inner region could result in a circum-terrestrial debris disk with materials predominately from the proto-Earth without violating the angular momentum constraint. The theory proposed here may provide a viable way of explaining the similarity in the isotopic compositions of the Earth and Moon.

astro-ph.EP↗

arXiv2025

Detecting extremely low frequency primordial gravitational wave by gravitational lens system

Primordial gravitational waves (PGWs) are predicted to origin from inflation, according to which a period of accelerated expansion exists in the very early Universe. The detection of PGWs would verify the inflationary theory and determine its energy scale. The traditional method of using B-mode polarization to detect extremely low frequency PGW faces challenges due to the contamination from dust in Milky Way. We investigated the feasibility of using gravitational lens system (GLS) with source of high redshift to detect extremely low frequency PGW. With GLS perturbed by extremely low frequency PGWs, we found that the observed time delay in GLS could strongly deviate from the theoretical one, such strong deviation is the evidence of extremely low frequency PGWs.

gr-qc↗

arXiv2024

Gravitational Lens System as a Long Baseline Detector of Extremely Low Frequency Primordial Gravitational Wave

The effect of extremely low frequency primordial gravitational wave with arbitrary direction of propagation on a non-aligned gravitational lens system is investigated. From the point of view of real astrophysical lens model, singular isothermal sphere lens model is adopted in the gravitational lens system. The results show that, under the perturbation from extremely low frequency primordial gravitational wave, time delay in the gravitational lens system could strongly deviate from that deduced from theoretical model. This means that the strongly deviate time delay could be the imprint of extremely low frequency primordial gravitational wave on gravitational lens system, indicating that gravitational lens system could be used as a long baseline detector to detect extremely low frequency primordial gravitational wave.

gr-qc↗

arXiv2024

Retrograde Ring Formed Around Eccentric Extrasolar Giant Planet

We investigate the accretion flow around a giant planet using two-dimensional hydrodynamical simulations by studying the local region of accretion disk around the planet. The results show that, when the initial orbit of the planet embedded in protoplanetary disk is eccentric, the accretion disk formed around the planet is retrograde during the evolution and may be a possible origin of the retrograde ring around eccentric extrasolar giant planet.

astro-ph.EP↗

arXiv2024

Formation of Retrograde Hot Jupiter Triggered by Close Encounter with Tidal Circularization

A new mechanism is proposed to account for the formation of retrograde hot Jupiter in coplanar star-planet system via close encounter between a Jupiter mass planet and a brown dwarf mass planet. After long timescale scattering between several Jupiter mass planets with inner orbits, the remaining planets still rotating around the star could have large semimajor with large eccentricity. If there exists a brown dwarf mass planet in distant orbit around the star, planetary encounter may happen. After encounter, the Jupiter mass planet may rotate around the star in a retrograde orbit with extremely large eccentricity and the periastron can reach about 0.01 AU, which means that, within the first several orbits around the star, tidal interaction from the star can shrink the semimajor axis of the planet quickly. Thus, the Jupiter mass planet is isolated from the brown dwarf mass planet due to the quick decrease of its apastron distance and eventually evolves into a retrograde hot Jupiter.

astro-ph.EP↗

arXiv2024

When Digital Twin Meets 6G: Concepts, Obstacles, and Research Prospects

The convergence of digital twin technology and the emerging 6G network presents both challenges and numerous research opportunities. This article explores the potential synergies between digital twin and 6G, highlighting the key challenges and proposing fundamental principles for their integration. We discuss the unique requirements and capabilities of digital twin in the context of 6G networks, such as sustainable deployment, real-time synchronization, seamless migration, predictive analytic, and closed-loop control. Furthermore, we identify research opportunities for leveraging digital twin and artificial intelligence to enhance various aspects of 6G, including network optimization, resource allocation, security, and intelligent service provisioning. This article aims to stimulate further research and innovation at the intersection of digital twin and 6G, paving the way for transformative applications and services in the future.

cs.NI↗

arXiv2024

Two-Timescale Synchronization and Migration for Digital Twin Networks: A Multi-Agent Deep Reinforcement Learning Approach

Digital twins (DTs) have emerged as a promising enabler for representing the real-time states of physical worlds and realizing self-sustaining systems. In practice, DTs of physical devices, such as mobile users (MUs), are commonly deployed in multi-access edge computing (MEC) networks for the sake of reducing latency. To ensure the accuracy and fidelity of DTs, it is essential for MUs to regularly synchronize their status with their DTs. However, MU mobility introduces significant challenges to DT synchronization. Firstly, MU mobility triggers DT migration which could cause synchronization failures. Secondly, MUs require frequent synchronization with their DTs to ensure DT fidelity. Nonetheless, DT migration among MEC servers, caused by MU mobility, may occur infrequently. Accordingly, we propose a two-timescale DT synchronization and migration framework with reliability consideration by establishing a non-convex stochastic problem to minimize the long-term average energy consumption of MUs. We use Lyapunov theory to convert the reliability constraints and reformulate the new problem as a partially observable Markov decision-making process (POMDP). Furthermore, we develop a heterogeneous agent proximal policy optimization with Beta distribution (Beta-HAPPO) method to solve it. Numerical results show that our proposed Beta-HAPPO method achieves significant improvements in energy savings when compared with other benchmarks.

cs.ET↗

arXiv2024

Is Lensing Amplitude Anomaly in the Cosmic Microwave Background the Evidence of Extremely Low Frequency Primordial Gravitational Wave?

Trajectories of photons of cosmic microwave background (CMB) from the surface of last scattering to us could be deflected by extremely low frequency primordial gravitational wave (PGW). With large scale structure (LSS) producing a smoothing of the acoustic peaks in the power spectrum of the CMB anisotropies through weak lensing, the presence of extremely low frequency PGW could enhance the effect of weak lensing on CMB due to the coupling of extremely low frequency PGW and LSS, thus, give rise to much more smoothing of the spectrum. This may be an natural explanation for the lensing amplitude anomaly observed by Planck, meaning that lensing amplitude anomaly may be the evidence of extremely low frequency PGW.

astro-ph.HE↗

arXiv2023

Interaction of eccentric supermassive binary black hole with intermediate mass ratio and circumbinary accretion disk

Recent simulations show that the eccentricity of supermassive binary black hole with intermediate mass ratio could grow toward near unity through gravitational interaction with the stellar background in the merging remnant after two galaxies merge. The increased eccentricity reduces the timescale of the supermassive binary black hole merger through the strong gravitational radiation at periastron. Usually, large amount of gas flows toward the center of the newly merged galaxy, forming circumbinary gaseous disk around the binary in the center of the newly merged galaxy. Tidal interaction between such eccentric binary with intermediate mass ratio and circumbinary disk need to be investigated quantitatively. In this work, we study the gravitational interaction of the eccentric supermassive binary black hole with intermediate mass ratio and the circumbinary disk using code FARGO3D. Simulations are carried out with different semimajor, eccentricity and mass ratio. We find that the accretion rate onto the inner boundary could be strongly affected by the secondary black hole and tend to present periodic accretion rate in some situations. Such periodic accretion rate can be used as electromagnetic counterpart to the gravitational wave radiated by such kind of eccentric binary.

astro-ph.HE↗

arXiv2023

Adaptive Digital Twin for UAV-Assisted Integrated Sensing, Communication, and Computation Networks

In this paper, we study a digital twin (DT)-empowered integrated sensing, communication, and computation network. Specifically, the users perform radar sensing and computation offloading on the same spectrum, while unmanned aerial vehicles (UAVs) are deployed to provide edge computing service. We first formulate a multi-objective optimization problem to minimize the beampattern performance of multi-input multi-output (MIMO) radars and the computation offloading energy consumption simultaneously. Then, we explore the prediction capability of DT to provide intelligent offloading decision, where the DT estimation deviation is considered. To track this challenge, we reformulate the original problem as a multi-agent Markov decision process and design a multi-agent proximal policy optimization (MAPPO) framework to achieve a flexible learning policy. Furthermore, the Beta-policy and attention mechanism are used to improve the training performance. Numerical results show that the proposed method is able to balance the performance tradeoff between sensing and computation functions, while reducing the energy consumption compared with the existing studies.

eess.SP↗

arXiv2023

Energy Efficient Computation Offloading in Aerial Edge Networks With Multi-Agent Cooperation

With the high flexibility of supporting resource-intensive and time-sensitive applications, unmanned aerial vehicle (UAV)-assisted mobile edge computing (MEC) is proposed as an innovational paradigm to support the mobile users (MUs). As a promising technology, digital twin (DT) is capable of timely mapping the physical entities to virtual models, and reflecting the MEC network state in real-time. In this paper, we first propose an MEC network with multiple movable UAVs and one DT-empowered ground base station to enhance the MEC service for MUs. Considering the limited energy resource of both MUs and UAVs, we formulate an online problem of resource scheduling to minimize the weighted energy consumption of them. To tackle the difficulty of the combinational problem, we formulate it as a Markov decision process (MDP) with multiple types of agents. Since the proposed MDP has huge state space and action space, we propose a deep reinforcement learning approach based on multi-agent proximal policy optimization (MAPPO) with Beta distribution and attention mechanism to pursue the optimal computation offloading policy. Numerical results show that our proposed scheme is able to efficiently reduce the energy consumption and outperforms the benchmarks in performance, convergence speed and utilization of resources.

eess.SP↗