arXiv subjects

Jiang Xiao

Publications and source records attributed to Jiang Xiao.

At least 37 records · Page 2Linked to original sources

arXiv2024

All Your Tokens are Belong to Us: Demystifying Address Verification Vulnerabilities in Solidity Smart Contracts

In Ethereum, the practice of verifying the validity of the passed addresses is a common practice, which is a crucial step to ensure the secure execution of smart contracts. Vulnerabilities in the process of address verification can lead to great security issues, and anecdotal evidence has been reported by our community. However, this type of vulnerability has not been well studied. To fill the void, in this paper, we aim to characterize and detect this kind of emerging vulnerability. We design and implement AVVERIFIER, a lightweight taint analyzer based on static EVM opcode simulation. Its three-phase detector can progressively rule out false positives and false negatives based on the intrinsic characteristics. Upon a well-established and unbiased benchmark, AVVERIFIER can improve efficiency 2 to 5 times than the SOTA while maintaining a 94.3% precision and 100% recall. After a large-scale evaluation of over 5 million Ethereum smart contracts, we have identified 812 vulnerable smart contracts that were undisclosed by our community before this work, and 348 open source smart contracts were further verified, whose largest total value locked is over $11.2 billion. We further deploy AVVERIFIER as a real-time detector on Ethereum and Binance Smart Chain, and the results suggest that AVVERIFIER can raise timely warnings once contracts are deployed.

cs.CR↗

arXiv2024

Mechanism for the Broadened Linewidth in Antiferromagnetic Resonance

The linewidth of antiferromagnetic resonance (AFMR) is found to be significantly broader than that of ferromagnetic resonance (FMR), even when the intrinsic Gilbert damping parameter is the same for both systems. We investigate the origin of this enhanced damping rate in AFMR by studying a bipartite magnet model. Through analytical calculations and numerical simulations, we present three perspectives on understanding this linewidth broadening in AFMR: i) The non-dissipative Heisenberg exchange interaction develops a damping-like component in the presence of Gilbert damping, ii) The transverse component of the exchange coupling reduces the AFMR frequency, thereby increasing the damping rate, and iii) The antiferromagnetic eigenmode exhibits characteristics of a two-mode squeezed state, which is inherently linked to an enhanced damping rate. Our findings provide a comprehensive understanding of the complex dynamics governing magnetic dissipation in antiferromagnet and offer insights into the experimentally observed broadened linewidths in AFMR spectra.

cond-mat.mes-hall↗

arXiv2024

Application of Probabilistic-bit in Precision Measurements

We propose a novel approach for precision measurement utilizing an ensemble of probabilistic bits (p-bits). This method leverages the inherent fluctuations of p-bits to achieve high sensitivity in various applications, including magnetic field sensing, temperature monitoring and timekeeping. The sensitivity scales proportionally to the square root of the total number of p-bits, enabling unprecedented accuracy with large ensembles. Furthermore, the robustness of this method against device imperfections and non-uniformity enhances its practicality and scalability. This work paves the way for a new paradigm in precision measurement, offering a cost-effective and versatile alternative to traditional methods.

physics.app-ph↗

arXiv2024

Interpreting S-Parameter Spectra in Coupled Resonant Systems: The Role of Probing Configurations

The S-parameter $S_{21}$ is widely used to characterize the resonant properties of various systems. However, we demonstrates that the reliability of $S_{21}$ as a true indicator of system resonances depends heavily on the specific probing setup employed. While point-probe or weak probes preserve the integrity of the $S_{21}$ spectrum and accurately reflect system resonances, multi-point and strong probes can introduce significant discrepancies. These discrepancies can manifest as misleading features such as repulsive level anti-crossing or attractive level crossing, even in systems that are fundamentally uncoupled. This highlights the critical importance of selecting appropriate probing techniques to ensure a precise evaluation of system resonances.

cond-mat.mes-hall↗

arXiv2023

A Deep Dive into NFT Rug Pulls

NFT rug pull is one of the most prominent type of scam that the developers of a project abandon it and then run away with investors' funds. Although they have drawn attention from our community, to the best of our knowledge, the NFT rug pulls have not been systematically explored. To fill the void, this paper presents the first in-depth study of NFT rug pulls. Specifically, we first compile a list of 253 known NFT rug pulls as our initial ground truth, based on which we perform a pilot study, highlighting the key symptoms of NFT rug pulls. Then, we enforce a strict rule-based method to flag more rug pulled NFT projects in the wild, and have labelled 7,487 NFT rug pulls as our extended ground truth. Atop it, we have investigated the art of NFT rug pulls, with kinds of tricks including explicit ones that are embedded with backdoors, and implicit ones that manipulate the market. To release the expansion of the scam, we further design a prediction model to proactively identify the potential rug pull projects in an early stage ahead of the scam happens. We have implemented a prototype system deployed in the real-world setting for over 5 months. Our system has raised alarms for 7,821 NFT projects, by the time of this writing, which can work as a whistle blower that pinpoints rug pull scams timely, thus mitigating the impacts.

cs.CR↗

arXiv2022

Blockchain-based Federated Learning for Industrial Metaverses: Incentive Scheme with Optimal AoI

The emerging industrial metaverses realize the mapping and expanding operations of physical industry into virtual space for significantly upgrading intelligent manufacturing. The industrial metaverses obtain data from various production and operation lines by Industrial Internet of Things (IIoT), and thus conduct effective data analysis and decision-making, thereby enhancing the production efficiency of the physical space, reducing operating costs, and maximizing commercial value. However, there still exist bottlenecks when integrating metaverses into IIoT, such as the privacy leakage of sensitive data with commercial secrets, IIoT sensing data freshness, and incentives for sharing these data. In this paper, we design a user-defined privacy-preserving framework with decentralized federated learning for the industrial metaverses. To further improve privacy protection of industrial metaverse, a cross-chain empowered federated learning framework is further utilized to perform decentralized, secure, and privacy-preserving data training on both physical and virtual spaces through a hierarchical blockchain architecture with a main chain and multiple subchains. Moreover, we introduce the age of information as the data freshness metric and thus design an age-based contract model to motivate data sensing among IIoT nodes. Numerical results indicate the efficiency of the proposed framework and incentive mechanism in the industrial metaverses.

cs.GT↗

arXiv2022

Spin wave driven domain wall motion in easy-plane ferromagnets: a particle perspective

In easy-plane ferromagnets, we show that the interplay between a domain wall and a spin wave packet can be formulated as the collision of two massive particles with a gravity-like attraction. In the presence of magnetic dissipation, the domain wall mimics a particle subject to viscous friction, while the spin wave packet resembles a particle of variable mass. Due to attractive nature of the interaction, the domain wall acquires a backward displacement as a spin wave packet penetrating the domain wall, even though there is no change in momentum of the wave packet before and after penetration.

cond-mat.mes-hall↗

arXiv2021

Antiferromagnetic Resonance Revisited: Dissipative Coupling without Dissipation

The antiferromagnet is a closed Hermitian system, we find that its excitations, even in the absence of dissipation, can be viewed as a non-Hermitian system with dissipative coupling. Consequently, the antiferromagnetic resonance spectrum does not show the typical level repulsion, but shows the level attraction -- a characteristic behavior often observed in non-Hermitian systems. Such behavior is because the antiferromagnetic ground state is $\mathcal{PT}$-symmetric. This new understanding on antiferromagnetic resonance also explains the mysterious enhancement of antiferromagnetic damping rate. Being effectively non-Hermitian, antiferromagnetic magnons can be used for quantum entanglement generation without introducing a third party like external pumping.

cond-mat.mes-hall↗

arXiv2021

Electrically Switchable van der Waals Magnon Valves

Van der Waals magnets have emerged as a fertile ground for the exploration of highly tunable spin physics and spin-related technology. Two-dimensional (2D) magnons in van der Waals magnets are collective excitation of spins under strong confinement. Although considerable progress has been made in understanding 2D magnons, a crucial magnon device called the van der Waals magnon valve, in which the magnon signal can be completely and repeatedly turned on and off electrically, has yet to be realized. Here we demonstrate such magnon valves based on van der Waals antiferromagnetic insulator MnPS3. By applying DC electric current through the gate electrode, we show that the second harmonic thermal magnon (SHM) signal can be tuned from positive to negative. The guaranteed zero crossing during this tuning demonstrates a complete blocking of SHM transmission, arising from the nonlinear gate dependence of the non-equilibrium magnon density in the 2D spin channel. Using the switchable magnon valves we demonstrate a magnon-based inverter. These results illustrate the potential of van der Waals anti-ferromagnets for studying highly tunable spin-wave physics and for application in magnon-base circuitry in future information technology.

cond-mat.mtrl-sci↗

arXiv2021

Narrow waveguide based on ferroelectric domain wall

Ferroelectric materials are spontaneous symmetry breaking systems characterized by ordered electric polarizations. Similar to its ferromagnetic counterpart, a ferroelectric domain wall can be regarded as a soft interface separating two different ferroelectric domains. Here we show that two bound state excitations of electric polarization (polar wave), or the vibration and breathing modes, can be hosted and propagate within the ferroelectric domain wall. Specially, the vibration polar wave has zero frequency gap, thus is constricted deeply inside ferroelectric domain wall, and can propagate even in the presence of local pinnings. The ferroelectric domain wall waveguide as demonstrated here, offers new paradigm in developing ferroelectric information processing units.

cond-mat.mtrl-sci↗

arXiv2021

Unconventional magnon excitation by off-resonant microwaves

It is widely recognized that a physical system can only respond to a periodic driving significantly when the driving frequency matches the normal mode frequency of the system, which leads to resonance. Off-resonant phenomena are rarely considered because of the difficulty to realize strong coupling between physical systems and off-resonant waves. Here we examine the response of a magnetic system to squeezed light and surprisingly find that the magnons are maximally excited when the effective driving frequency is several orders of magnitude larger than the resonant frequency. The generated magnons are squeezed which brings the advantage of tunable squeezing through an external magnetic field. Furthermore, we demonstrate that such off-resonant quasi-particle excitation is universal in all the hybrid systems in which the coherent and parametric interaction of bosons exists and that it is purely a quantum effect, which is rooted in the quantum fluctuations of particles in the squeezed vacuum. Our findings may provide an unconventional route to study off-resonant phenomena and may further benefit the use of hybrid matter-light systems in continuous variable quantum information.

cond-mat.mes-hall↗

arXiv2021

A Hopfield neural network in magnetic films with natural learning

Macroscopic spin ensembles possess brain-like features such as non-linearity, plasticity, stochasticity, selfoscillations, and memory effects, and therefore offer opportunities for neuromorphic computing by spintronics devices. Here we propose a physical realization of artificial neural networks based on magnetic textures, which can update their weights intrinsically via built-in physical feedback utilizing the plasticity and large number of degrees of freedom of the magnetic domain patterns and without resource-demanding external computations. We demonstrate the idea by simulating the operation of a 4-node Hopfield neural network for pattern recognition.

cond-mat.dis-nn↗

arXiv2020

Geometric magnonics with chiral magnetic domain walls

Spin wave, the collective excitation of magnetic order, is one of the fundamental angular momentum carriers in magnetic systems. Understanding the spin wave propagation in magnetic textures lies in the heart of developing pure magnetic information processing schemes. Here we show that the spin wave propagation across a chiral domain wall follows simple geometric trajectories, similar to the geometric optics. And the geometric behaviors are qualitatively different in normally magnetized film and tangentially magnetized film. We identify the lateral shift, refraction, and total reflection of spin wave across a ferromagnetic domain wall. Moreover, these geometric scattering phenomena become polarization-dependent in antiferromagnets, indicating the emergence of spin wave birefringence inside antiferromagnetic domain wall.

cond-mat.mtrl-sci↗

arXiv2020

Magnetic texture based magnonics

The spontaneous magnetic orders arising in ferro-, ferri- and antiferromagnets stem from various magnetic interactions. Depending on the interplay and competition among the Heisenberg exchange interaction, Dzyaloshinskii-Moriya exchange interaction, magnetic dipolar interaction and crystal anisotropies, a great variety of magnetic textures may be stabilized, such as magnetic domain walls, vortices, Skyrmions and spiral helical structures. While each of these spin textures responds to external forces in a specific manner with characteristic resonance frequencies, they also interact with magnons, the fundamental collective excitation of the magnetic order, which can propagate in magnetic materials free of charge transport and therefore with low energy dissipation. Recent theories and experiments found that the interplay between spin waves and magnetic textures is particularly interesting and rich in physics. In this review, we introduce and discuss the theoretical framework of magnons living on a magnetic texture background, as well as recent experimental progress in the manipulation of magnons via magnetic textures. The flexibility and reconfigurability of magnetic textures are discussed regarding the potential for applications in information processing schemes based on magnons.

physics.app-ph↗

arXiv2020

Skew scattering and side jump of spin wave across magnetic texture

Spin wave and magnetic texture are two elementary excitations in magnetic systems, and their interaction leads to rich magnetic phenomena. By describing the spin wave and the magnetic texture using their own collective coordinates, we find that they interact as classical particles traveling in mutual electromagnetic fields. Based on this unified collective coordinate model, we find that both skew scattering and side jump may occur as spin wave passing through magnetic textures. The skew scattering is associated with the magnetic topology of the texture, while the side jump is correlated to the total magnetization of the texture. We illustrate the concepts of skew scattering and side jump by investigating the spin wave trajectories across the topological magnetic Skyrmion and the topologically trivial magnetic bubble respectively.

cond-mat.mtrl-sci↗

arXiv2020

Giant spin transfer torque in atomically thin magnetic bilayers

In cavity quantum electrodynamics, the multiple reflections of a photon between two mirrors defining a cavity is exploited to enhance the light-coupling of an intra-cavity atom. We show that this paradigm for enhancing the interaction of a flying particle with a localized object can be generalized to spintronics based on van der Waals 2D magnets. Upon tunneling through a magnetic bilayer, we find the spin transfer torques per electron incidence can become orders of magnitude larger than $\hbar/2$, made possible by electron's multi-reflection path through the ferromagnetic monolayers as an intermediate of their angular momentum transfer. Over a broad energy range around the tunneling resonances, the damping-like spin transfer torque per electron tunneling features a universal value of $\frac{\hbar}{2} \tan{\fracθ{2}}$, depending only on the angle $θ$ between the magnetizations. These findings expand the scope of magnetization manipulations for high-performance and high-density storage based on van der Waals magnets.

cond-mat.mes-hall↗

arXiv2020

Dynamical magnetoelectric coupling in axion insulator thin films

Axion insulator is an exotic magnetic topological insulator with zero Chern number but a nonzero quantized Chern-Simons magnetoelectric coupling. A conclusive experimental evidence for axion insulators is still lacking due to the small signal of topological magnetoelectric effect (TME). Here we show that the dynamical magnetoelectric coupling can be induced by the \emph{out-of-plane} surface magnetization dynamics in axion insulator thin films, which further generates a polarization current in the presence of an external magnetic field in the same direction. Such a current is finite in the bulk and increases as the film thickness $d$ decreases, in opposite to TME current which decreases as $d$ decreases. Remarkably, the current in thin films at magnetic resonance is at least ten times larger than that of TME, and thus may serve as a smoking gun signature for axion insulators.

cond-mat.mes-hall↗

arXiv2020

Spin wave based tunable switch between superconducting flux qubits

Quantum computing hardware has received world-wide attention and made considerable progress recently. YIG thin film have spin wave (magnon) modes with low dissipation and reliable control for quantum information processing. However, the coherent coupling between a quantum device and YIG thin film has yet been demonstrated. Here, we propose a scheme to achieve strong coupling between superconducting flux qubits and magnon modes in YIG thin film. Unlike the direct $\sqrt{N}$ enhancement factor in coupling to the Kittel mode or other spin ensembles, with N the total number of spins, an additional spatial dependent phase factor needs to be considered when the qubits are magnetically coupled with the magnon modes of finite wavelength. To avoid undesirable cancelation of coupling caused by the symmetrical boundary condition, a CoFeB thin layer is added to one side of the YIG thin film to break the symmetry. Our numerical simulation demonstrates avoided crossing and coherent transfer of quantum information between the flux qubits and the standing spin waves in YIG thin films. We show that the YIG thin film can be used as a tunable switch between two flux qubits, which have modified shape with small direct inductive coupling between them. Our results manifest that it is possible to couple flux qubits while suppressing undesirable cross-talk.

quant-ph↗