arXiv subjects

Ya Chen

Publications and source records attributed to Ya Chen.

3 recordsLinked to original sources

arXiv2026

Quantifying Observable High-Frequency Swapping on Arbitrum

Layer-2 rollups have reshaped Ethereum's transaction economy by replacing mempool competition with deterministic sequencing, sub-second block times, and negligible gas fees. While these properties suppress classical Miner/Maximal Extractable Value (MEV), they give rise to a new and previously unrecognized behavioral regime. In this paper, we introduce the concept of High-Frequency Swapping (HFS), referring to continuous single-hop swaps at machine cadence within decentralized exchanges. Despite its growing footprint, this phenomenon has not been systematically identified or quantified in prior work. We conduct a large-scale measurement of HFS on Arbitrum, using 18 months of full-chain data (Jan. 2023--Jun. 2024). Specifically, we construct a reproducible pipeline that isolates voluntary single-swap transactions, attributes them to the swapper level, and classifies HFS behavior through inter-arrival dynamics. The analysis uncovers 477 distinct HFS swappers responsible for nearly 30 million swaps and over $10^{11}$ USD in notional volume. Our study conducts a comprehensive empirical investigation of HFS from multiple perspectives. We begin with a global overview of activity patterns, and then examine temporal dynamics, swapper identity, token coverage, and venue concentration, and explore swap size, time gap, and order direction. Finally, we explore case-level behavior, including stablecoin arbitrage, CEX-DEX execution gaps, and short-horizon round-trip trading. Across these dimensions, we identify consistent structural regularities that distinguish HFS from conventional retail or arbitrage activity. This work provides a large-scale address-level empirical characterization of High-Frequency Swapping on Arbitrum and a broad empirical foundation for future research on decentralized market microstructure.

cs.CR↗

arXiv2026

Boson peak and medium-range elastic heterogeneity in calcium silicate hydrate probed by terahertz spectroscopy and low-temperature calorimetry

The boson peak (BP), a universal vibrational anomaly of disordered solids, has been predicted but not systematically characterized in calcium silicate hydrate (C-S-H), the binding phase of hardened cement. Building on a preliminary terahertz survey, we characterize the BP across five Ca/Si ratios (0.5-1.7) using terahertz time-domain spectroscopy (THz-TDS) and low-temperature calorimetry, two probes of vibrational dynamics that complement the static picture of conventional structural methods. After Bruggeman correction for crystalline impurities, both probes locate the BP near 1 THz; they agree on frequency but diverge in intensity. The terahertz integrated spectral weight and the calorimetric Cp/T3 peak both fall monotonically with Ca/Si, whereas the apparent terahertz peak height is maximal at Ca/Si = 1.0, where damping is low and oscillator strength still substantial. This decoupling marks a structural crossover between silicate-chain depolymerization and interlayer calcium filling. From the BP we obtain a medium-range dynamical correlation length of order 1 nm (0.3-2 nm) and a coherent-potential elastic-heterogeneity parameter that decreases from gamma = 0.98 to 0.48 as Ca/Si rises; the Debye-normalized BP frequency (nu_BP/nu_D = 0.15-0.17) places C-S-H within the range reported for silicate glasses. Because gamma governs the distribution of energy barriers for local structural rearrangements, it provides a quantitative, composition-resolved descriptor relevant to the intrinsic creep and thermal transport of C-S-H, linking nanoscale vibrational dynamics to the macroscopic durability of concrete. The dual-probe boson-peak approach is transferable to other amorphous solids, including the supplementary cementitious materials of low-carbon cements.

cond-mat.mtrl-sci↗

arXiv2015

Broadband laser polarization control with aligned carbon nanotubes

We introduce a simple approach to fabricate aligned carbon nanotube (ACNT) device for broadband polarization control in fiber laser systems. The ACNT device was fabricated by pulling from as-fabricated vertically-aligned carbon nanotube arrays. Their anisotropic property is confirmed with optical and scanning electron microscopy, and with polarized Raman and absorption spectroscopy. The device was then integrated into fiber laser systems (at two technologically important wavelengths of 1 and 1.5 um) for polarization control. We obtained a linearly-polarized light output with the maximum extinction ratio of ~12 dB. The output polarization direction could be fully controlled by the ACNT alignment direction in both lasers. To the best of our knowledge, this is the first time that ACNT device is applied to polarization control in laser systems. Our results exhibit that the ACNT device is a simple, low-cost, and broadband polarizer to control laser polarization dynamics, for various photonic applications (such as material processing, polarization diversity detection in communications), where the linear polarization control is necessary.

physics.optics↗