arXiv subjects

Qingchen Li

Publications and source records attributed to Qingchen Li.

7 recordsLinked to original sources

arXiv2026

RhinoVLA Technical Report

Vision-Language-Action (VLA) models have shown strong potential for robotic manipulation, but real-time deployment on edge hardware remains challenging. In this work, we identify VLM visual and context tokens as a major source of deployment latency: for GEMM-dominated projection operators, computation grows linearly with the number of input tokens when model dimensions are fixed. Motivated by this observation, we propose RhinoVLA, a deployment-oriented VLA model co-designed with the Huixi R1 edge SoC. RhinoVLA adopts a token-efficient Qwen3-VL backbone and a continuous Action Expert, reducing the VLM-side token and computation burden while preserving pretrained multimodal capability. To support cross-robot learning, RhinoVLA further introduces a unified interface that combines View Registry, 72D physical state-action slot space, and robotinstance LoRA, allowing heterogeneous robot observations and action schemas to be aligned under a shared policy. On the deployment side, RhinoVLA is optimized through hardware-aware compilation, mixed-precision execution, and parallel visual encoding. Experiments show that RhinoVLA achieves downstream performance comparable to {\pi}0.5 at a similar parameter scale, while reaching 11.69 Hz end-to-end inference on Huixi R1, meeting the 10 Hz real-time closedloop control target. The project will be open-sourced at https://github.com/HuixiAI/RhinoVLA.

cs.RO↗

arXiv2026

Bound states of anyons: a geometric quantization approach

The question of anyon interactions and their possible binding plays a key role in the physics of fractional quantum Hall states. Here, we introduce a controlled and scalable approach to study anyon binding by working entirely within the Hilbert space of anyons. The resulting theory is characterized by an effective potential, which captures the electrostatic energy of classical anyon configurations, and a K\"ahler potential, which simultaneously encodes the anyon Berry phase and the structure of their Hilbert space; both quantities are readily computed using Monte Carlo methods for large systems, enabling reliable extrapolation to the thermodynamic limit. By applying the formalism of geometric quantization on K\"ahler manifolds, we construct the anyon Hamiltonian, which can be exactly diagonalized in the few-anyon Hilbert space. Applying our approach to the quasiholes of the $\nu=1/3$ Laughlin state with screened Coulomb interaction, we find that Laughlin quasiholes form bound states for screening lengths comparable or smaller than the magnetic length. Remarkably, binding occurs despite both the bare electron-electron interaction and the quasihole electrostatic potential being purely repulsive. The bound-state formation is a Berry phase effect, driven by oscillations in the quasihole density profile on the $\ell_B$ scale that are invisible in the quasihole electrostatic potential alone. For multiple quasiholes, we identify a sequence of phases as the screening length is reduced: free $e/3$ anyons, paired $2e/3$ bound states, three-anyon charge-$e$ clusters, and larger composite objects. Finally, we discuss possible signatures in charge imaging experiments on quantum Hall systems and the relevance to the phase diagram of itinerant anyon phases in fractional quantum anomalous Hall materials.

cond-mat.str-el↗

arXiv2026

DynSplit-KV: Dynamic Semantic Splitting for KVCache Compression in Efficient Long-Context LLM Inference

Although Key-Value (KV) Cache is essential for efficient large language models (LLMs) inference, its growing memory footprint in long-context scenarios poses a significant bottleneck, making KVCache compression crucial. Current compression methods rely on rigid splitting strategies, such as fixed intervals or pre-defined delimiters. We observe that rigid splitting suffers from significant accuracy degradation (ranging from 5.5% to 55.1%) across different scenarios, owing to the scenario-dependent nature of the semantic boundaries. This highlights the necessity of dynamic semantic splitting to match semantics. To achieve this, we face two challenges. (1) Improper delimiter selection misaligns semantics with the KVCache, resulting in 28.6% accuracy loss. (2) Variable-length blocks after splitting introduce over 73.1% additional inference overhead. To address the above challenges, we propose DynSplit-KV, a KVCache compression method that dynamically identifies delimiters for splitting. We propose: (1) a dynamic importance-aware delimiter selection strategy, improving accuracy by 49.9%. (2) A uniform mapping strategy that transforms variable-length semantic blocks into a fixed-length format, reducing inference overhead by 4.9x. Experiments show that DynSplit-KV achieves the highest accuracy, 2.2x speedup compared with FlashAttention and 2.6x peak memory reduction in long-context scenarios.

cs.LG↗

arXiv2025

Anyon Dispersion in Aharonov-Casher Bands and Implications for Twisted MoTe${}_2$

The discovery of fractional quantum anomalous Hall (FQAH) states in two-dimensional heterostructures has opened the door to realizing phases of dispersing anyons. Here, we develop an analytically controlled theory of anyon dispersion in FQAH states realized in ideal or Aharonov-Casher (AC) bands by projecting interactions onto the space of Laughlin quasiholes. Constructing quasihole momentum eigenstates allows efficient evaluation of the single quasihole dispersion using Monte Carlo. We find that the quasihole bandwidth grows with increasing quantum-geometry inhomogeneity of the AC band and with increasing interaction screening length. For realistic parameters relevant to the bands of twisted MoTe${}_2$, the quasihole bandwidth is of order 1 meV and increases with increasing displacement field, suggesting that itinerant-anyon physics may play an important role in sufficiently clean samples. Furthermore, we develop a microscopic Lagrangian framework in terms of a quasihole guiding-center coordinate, which reproduces the momentum-space formula for the dispersion. This approach reveals that quasihole dispersion originates from the combined effects of an interaction-generated periodic potential, arising from non-uniform quantum geometry of the single particle bands, and the quasihole many-body Berry phase arising from the background magnetic field. The latter endows the guiding-center coordinate with a noncommutative structure, converting the periodic potential into a finite dispersion. Finally, we outline how this framework generalizes to multiple quasiholes, enabling a microscopic theory of charged excitations in FQAH systems that retains only the anyon degrees of freedom.

cond-mat.str-el↗

arXiv2025

Statistical structural properties of many-body chaotic eigenfunctions and applications

In this paper, we employ a semiperturbative theory to study the statistical structural properties of energy eigenfunctions (EFs) in many-body quantum chaotic systems consisting of a central system coupled to an environment. Under certain assumptions, we derive both the average shape and the statistical fluctuations of EFs on the basis formed by the direct product of the energy eigenbases of the system and the environment. Furthermore, we apply our results to two fundamental questions: (i) the properties of the reduced density matrix of the central system in an eigenstate, and (ii) the structure of the off-diagonal smooth function within the framework of the eigenstate thermalization hypothesis. Numerical results are also presented in support of our main findings.

cond-mat.stat-mech↗

arXiv2024

Constraints on real space representations of Chern bands

A Chern band is characterized by a Wannier obstruction indicating the absence of a basis of complete, orthogonal, and exponentially-localized states. Here, we study the properties of real space bases of a Chern band obtained by relaxing either exponential localization or orthogonality and completeness. This yields two distinct real space representations of a band with Chern number $C$: (i) a basis of complete orthogonal Wannier states which decay as power-law and (ii) a basis of exponentially-localized overcomplete non-orthogonal coherent states. For (i), we show that the power-law tail only depends on the Chern number and provide an explicit gauge choice leading to the universal asymptotic $w({\boldsymbol r}) \approx \frac{C e^{-i C \varphi_{\boldsymbol r}}}{2\pi |{\boldsymbol r}|^2}$ up to a normalized Bloch-periodic spinor. For (ii), we prove a rigorous lower bound on the spatial spread that can always be saturated for ideal bands. We provide an explicit construction of the maximally localized coherent state by mapping the problem to a dual Landau level problem where the Berry curvature and trace of the quantum metric take the roles of an effective magnetic field and scalar potential, respectively. Our coherent state result rigorously bounds the spatial spread of any localized state constructed as a linear superposition of wavefunctions within the Chern band. Remarkably, we find that such bound does not generically scale with the Chern number and provide an explicit example of an exponentially localized state in a Chern $C$ band whose size does not increase with $|C|$. Our results show that band topology can be encoded in a real space description and set the stage for a systematic study of interaction effects in topological bands in real space.

cond-mat.str-el↗

arXiv2020

Non-existence of the s-f transition in structures of solid gadolinium at pressure

Gadolinium has long been believed to undergo a high pressure phase transition with a volume collapse around 5%. Theoretical explanations have focused on the idea of electrons transferring from the extended s-orbital to the compact f-orbital. However, experimental measurement has been unable to detect any associated change in the magnetic properties of the f-electrons. Here we resolve this discrepancy by showing that there is no significant volume collapse, beyond what is typical in high pressure phase transformations. We present density functional theory calculations of solid gadolinium under high pressure using a range of methods, and revisit the experimental situation using X-ray diffraction (XRD). The standard lanthanide pressure-transformation sequence involving different stackings of close-packed planes: hcp to 9R to dhcp to fcc to d-fcc is reproduced. The so-called "volume collapsed" high-pressure phase is shown to be an unusual stacking of close-packed planes, with Fddd symmetry and a density change less than 2%. The distorted fcc (d-fcc) structure is revealed to arise as a consequence of antiferromagnetism. The theoretical results are shown to be remarkably robust to various treatments of the f-electrons. The key result is that there is no XRD evidence for volume collapse in Gadolinium. The sequence of phase transitions is well described by standard DFT. There is no need for special treatment of the f-electrons or evidence of f-electron bonding. Noting previous spectroscopic evidence is that there is no change in the f-electrons we conclude that high pressure Gadolinium has no complicated f-electron physics such as Mott-Hubbard, Kondo or valence transition.

cond-mat.mtrl-sci↗