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Yunwen Liu

Publications and source records attributed to Yunwen Liu.

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Towards Decentralized Searcher Competition in MEV Markets

Centralization in maximal extractable value (MEV) markets is a significant concern for blockchain systems, as persistent concentration of economic power can weaken competition, reduce openness, and undermine the decentralization goals of permissionless protocols. While much of the existing analysis has focused on builders, validators, and block-building markets, this paper studies centralization from the perspective of searcher competition. We develop a heterogeneous model in which searchers differ in opportunity coverage and execution efficiency, and we analyze how auction design affects fairness, decentralization, and security among searchers competing for the same MEV opportunity. To evaluate searcher competition, we introduce two metrics: a Shapley-weighted Jain fairness index, which measures whether rewards are proportional to searchers' marginal contributions, and an expected-reward Herfindahl-Hirschman Index (HHI), which measures concentration in long-run searcher rewards. Using these metrics, we first analyze the standard first-price, winner-take-all auction as a benchmark. Our analysis shows that, under searcher heterogeneity, first-price competition can reward rank dominance rather than marginal contribution, leading to concentrated rewards and weaker contribution-adjusted fairness. Motivated by these limitations, we propose an entry-filtered Shapley-capped auction mechanism that distributes searcher rewards more fairly and broadly among admitted high-quality submissions. Designing such a mechanism in a permissionless blockchain environment is challenging: searchers may create Sybil identities by submitting copied or degraded versions of the same execution strategy, and validators may collude with searchers to increase joint payoff. We address these concerns through Bayesian security constraints for copied-code Sybil deviations and validator-searcher coalition deviations.

cs.GT

Order Flow Exclusivity and Value Extraction Mechanisms: An Analysis of Ethereum Builder Centralization

This study investigates the rapid centralization of the Ethereum builder market under the Proposer-Builder Separation (PBS) architecture. We argue that existing research, by focusing predominantly on influential order flows, lacks a comprehensive evaluation of order flow behavioral patterns and economic purposes. To address this gap, we analyze Ethereum transactions from September 2023 to August 2025 to characterize Exclusive Order Flows (EOFs) and non-atomic Maximal Extractable Value (MEV) -- the missing components corresponding to these behavioral and economic dimensions, respectively. We introduce a novel exclusivity metric based on Kullback-Leibler divergence and employ supervised learning to identify 75 EOFs and 322 non-atomic MEV flows, which account for 71\% and 23\% of trading-related builder revenue. A longitudinal analysis of builder strategies across these dimensions delineates the market's evolution into four distinct eras, revealing that while EOFs were instrumental in establishing early dominance, incumbents have since decoupled market share from immediate EOF dependency by leveraging entrenched network effects. Ultimately, we conclude that builder centralization is an emergent property of the PBS framework itself, as the architecture systematically violates the fundamental prerequisites of a competitive market.

cs.CR

Wave Computing based on Dynamical Networks: Applications in Optimization Problems

We develop a computing framework that leverages wave propagation within an interconnected network, where nodes and edges possess wave manipulation capabilities, such as frequency mixing or time delay. This computing paradigm can not only achieve intrinsic parallelism like existing works by the exploration of an exponential number of possibilities simultaneously with very small number of hardware units, but also extend this unique characteristic to a multidimensional space including spatial, temporal and frequency domains, making it particularly effective for addressing NP-hard problems. The proposed architecture has been validated through SPICE simulations, demonstrating its potential capability in solving several NP-hard problems, such as the Number Partitioning Problem, the 0/1 Knapsack Problem, and the Traveling Salesman Problem.

cs.ET

Alternating Spintronics: Capacitive Behavior of Spin Valves and Resonator Applications

This study explores the time-dependent spin transport phenomena in magnetic heterostructures under alternating currents (AC), advancing the relatively underdeveloped field of alternating spintronics. Employing a time-dependent spin diffusion model, we show that the interplay of AC frequencies and spin relaxation times reveals significant differences in spin accumulation patterns compared to conventional direct current (DC) scenarios. Of particular interest is the emergence of capacitive-like impedance in a spin valve under AC conditions, which is especially pronounced in antiparallel spin configurations. These findings open up possibilities for developing high-frequency spintronic devices, including the proposed "spin resonator", which functions like a standard LC resonator but without a traditional capacitor.

cond-mat.mes-hall

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