arXiv subjects

Xiaoyan Xu

Publications and source records attributed to Xiaoyan Xu.

8 recordsLinked to original sources

arXiv2026

Unveiling the Scaling Potential of Drain Merge through Active (DMtA) in CFETs: Breaking the Super-Via Bottlenecks and Unlocking New PPA Boosters

Drain merge (DM), a super via vertically connecting the common S/D terminals of stacked n/pFETs in Complementary FETs (CFETs), blocks further parasitic optimization and cell scaling. For the first time, this work systematically investigates the state-of-the-art Drain Merge through Active (DMtA), a revolutionary technology reported recently with the DM embedded in the active region, through a comprehensive DTCO framework spanning process integration, contact-configuration-dependent (CTCD) compact modeling, standardcell design, RO evaluation and block-level PPA benchmark on a 32-bit RISC-V Ibex core. By reducing DM parasitics and enabling DM-width optimization, DMtA improves RO frequency by 11.7% over its conventional Drain Merge through field (DMtF) counterpart. Active widening and Area Borrowing, the latter first reported in [8] and exploiting spatial slack in adjacent cells to further enlarge the nanosheet width (WNS), increase the maximum Ibex-core frequency by up to 34.8%. More importantly, DMtA also enables the once GAA-exclusive Hyper-cells on CFETs by merging the active regions across adjacent cell rows, providing a further 8.7% frequency gain. A post-routing floating-output-pin-aware optimization further removes redundant S/D contacts (CTs) and reduces power by 5.3%. Finally, DMtA facilitates more area-efficient 2.5T cell scaling by preserving single-row cell compatibility, reducing post-PR core area by 25.7%.

cond-mat.mes-hall↗

arXiv2025

Planar graphs without cycles of length 4 or 5 are $(7m:2m)$-DP-colorable

It was conjectured by Steinberg in 1976 that planar graphs without cycles of length 4 or 5 are 3-colorable. This conjecture attracted a substantial amount of attention and was finally refuted by Cohen-Addad, Hebdige, Král', Li and Salgado in 2017. Although Steinberg's conjecture is settled, coloring of this family of graphs, as well as some other families of planar graphs forbidding certain cycle lengths have been attracting a lot of recent attention and many challenging problems remain open. One problem of interest is multiple coloring and multiple list coloring of this family of graphs. It was proved by Dvǒrák and Hu that planar graphs without cycles of length 4 or 5 are $(11,3)$-colorable, and this result was improved by Wang, who proved that graphs in this family are $(7:2)$-colorable. On the other hand, it was proved by Xu and Zhu that for every positive integer $m$, there is a graph in this family which is not $(3m + \lfloor \frac{m-1}{12} \rfloor, m)$-choosable. In this paper, we prove that for any positive integer $m$, graphs in this family are $(7m:2m)$-DP-colorable, and hence $(7m,2m)$-choosable.

math.CO↗

arXiv2025

Physics-informed Temporal Alignment for Auto-regressive PDE Foundation Models

Auto-regressive partial differential equation (PDE) foundation models have shown great potential in handling time-dependent data. However, these models suffer from the shortcut problem deeply rooted in auto-regressive prediction, causing error accumulation. The challenge becomes particularly evident for out-of-distribution data, as the pretraining performance may approach random model initialization for downstream tasks with long-term dynamics. To deal with this problem, we propose physics-informed temporal alignment (PITA), a self-supervised learning framework inspired by inverse problem solving. Specifically, PITA aligns the physical dynamics discovered at different time steps on each given PDE trajectory by integrating physics-informed constraints into the self-supervision signal. The alignment is derived from observation data without relying on known physics priors, indicating strong generalization ability to the out-of-distribution data. Extensive experiments show that PITA significantly enhances the accuracy and robustness of existing foundation models on diverse time-dependent PDE data. The code is available at https://github.com/SCAILab-USTC/PITA.

cs.LG↗

arXiv2025

Doing Less for More: Consumer Search and Undertreatment in Credence Service Markets

In many service markets, expert providers possess an information advantage over consumers regarding the necessary services, creating opportunities for fraudulent practices. These may involve overtreatment through unnecessary services or undertreatment with ineffective solutions that fail to address consumers' problems. When issues are resolved, consumers exit the market; when unresolved, they must decide whether to revisit the initial provider or seek a new one. Little is known about how repeated interactions and the consumer search process influence expert fraud and consumer welfare in such markets. We develop a dynamic game-theoretic model to examine the role of consumer search behavior and repeated interactions between consumers and service providers. We find that overtreatment and undertreatment can arise simultaneously in equilibrium. Interestingly, undertreatment-being less costly for the consumer-can initially act as a "hook" to induce acceptance of a minor treatment recommendation. When this minor treatment fails to resolve the issue, it can generate additional demand for a more expensive and serious treatment. This would arise when the cost of revisiting the initial provider is lower than that of searching for a new one. The extent of undertreatment exhibits a non-monotonic relationship with consumers' ex ante belief about the nature of their problems and the market's ethical level. Our results can shed light on how market ethical levels, provider capabilities and capacities, and consumer privacy protection policies interact with undertreatment and affect consumer welfare. Specifically, consumer welfare can decrease as the market becomes more ethical. Enhancing providers' diagnostic capabilities and capacities can exacerbate undertreatment. Providing access to consumers' diagnosis histories can help mitigate the undertreatment issue and improve consumer welfare.

econ.TH↗

arXiv2024

Solutions and stochastic averaging for delay-path-dependent stochastic variational inequalities in infinite dimensions

In this paper, we study a very general stochastic variational inequality(SVI) having jumps, random coefficients, delay, and path dependence, in infinite dimensions. Well-posedness in terms of the existence and uniqueness of a solution is established, and a stochastic averaging principle on strong convergence of a time-explosion SVI to an averaged equation is obtained, both under non-Lipschitz conditions. We illustrate our results on general but concrete examples of finite dimension and infinite dimension respectively, which cover large classes of particle systems with electro-static repulsion, nonlinear stochastic partial differential equations with jumps, semilinear stochastic partial differential equations (especially stochastic reaction-diffusion equations) with delays, and others.

math.PR↗

arXiv2024

Central limit theorems for the derivatives of self-intersection local time for $d$-dimensional Brownian motion

Let $\{B_t,t\geq0\}$ be a d-dimensional Brownian motion. We prove that the approximation of the higher derivative of renormalized self-intersection local time $$ \int_{0}^{1}\int_{0}^{s}\left(p^{(|k|)}_{d,ε}(B_{s}-B_{r})-E[p^{(|k|)}_{d,ε}(B_{s}-B_{r})]\right)drds, $$ where the multiindex $k=(k_{1},\cdots,k_{d})$, $ p_{d,ε}^{(|k|)}(x_1,x_2,\cdots,x_d):=\partial^{k_1}_{x_1}\partial^{k_2}_{x_2}$ $\cdots\partial^{k_d}_{x_d}p_{d,ε}(x_1,x_2,\cdots,x_d)$ and $p_{d,ε}(x)=\frac{1}{(2πε)^{d/2}}e^{-\frac{|x|^{2}}{2ε}}, x\in\mathbb{R}^d$, satisfies the central limit theorems when renormalized by $(\log\frac{1}ε)^{-1}$ in the case $d=2$, $|k|=1$ and by $ε^{\frac{d+|k|-3}{2}}$ in the case $d\geq 3$, $|k|\geq 1$, which gives a complete answer to the conjecture of Markowsky [In Séminaire de Probabilitiés \uppercase\expandafter{\romannumeral10\romannumeral50\romannumeral4} (2012) 141-148 Springer]. We as well prove that its m-th Wiener chaotic component satisfies the central limit theorems when renormalized by a multiplicative factor in different cases.

math.PR↗

arXiv2019

Synergistic Effect of One- and Two-dimensional Connected Coral-like Li$_{6.25}$Al$_{0.25}$La$_3$Zr$_2$O$_{12}$ in PEO-Based Composite Solid State Electrolyte

As one of the most promising next-generation energy storage device, lithium metal batteries have been extensively investigated. However, the poor safety issue and undesired lithium dendrites growth hinder the development of lithium metal batteries. The application of solid state electrolytes has attracted increasing attention as they can solve the safety issue and partly inhibit the growth of lithium dendrites. Polyethylene oxide (PEO)-based electrolytes are very promising due to their enhanced safety and excellent flexibility. However, PEO-based electrolytes suffer from low ionic conductivity at room temperature and can't effectively inhibit lithium dendrites at high temperature due to the intrinsic semi-crystalline properties and poor mechanical strength. In this work, a novel coral-like Li6.25Al0.25La3Zr2O12 (LALZO) is synthesized to use as an active ceramic filler in PEO. The PEO with LALZO coral (PLC) exhibits increased ionic conductivity and mechanical strength, which leads to the uniform deposition/stripping of lithium metal. The Li symmetric cells with PLC cycle for 1500 h without short circuit at 50 centidegree. The assembled LiFePO4/PLC/Li batteries display excellent cycling stability at both 60 and 50 centidegree. This work reveals that the electrochemical properties of organic and inorganic composite electrolyte can be effectively improved by tuning the microstructure of the filler, such as the coral-like LALZO architecture.

physics.chem-ph↗

arXiv2015

Topological nature of FeSe$_{0.5}$Te$_{0.5}$ superconductor

We demonstrate, using first-principles calculations, that the electronic structure of FeSe$_{1-x}$Te$_{x}$ ($x$=0.5) is topologically non-trivial, characterized by an odd $\mathbb Z_2$ invariant and Dirac cone type surface states, in sharp contrast to the end member FeSe ($x$=0). This topological state is induced by the enhanced three-dimensionality and spin-orbit coupling due to Te substitution (compared to FeSe), characterized by a band inversion at the $Z$ point of the Brillouin zone, which is confirmed by our ARPES measurements. The results suggest that the surface of FeSe$_{0.5}$Te$_{0.5}$ may support a non-trivial superconducting channel in proximity to the bulk.

cond-mat.mtrl-sci↗