papers

Publications (19)

physics.geo-ph2025

Exact closed-form solutions for Lamb's problem (III): The case for buried source and receiver

Xi Feng, Haiming Zhang

In this article, we derive the exact closed-form solution for the displacement in the interior of an elastic half-space due to a buried point force with Heaviside step function tim…

physics.optics2025

Electric-Magnetic-Switchable Free-Space Skyrmions in Toroidal Light Pulses via a Nonlinear Metasurface

Li Niu, Xi Feng, Xueqian Zhang +10

Recent advances reveal that light propagation in free space supports many exotic topological textures, such as skyrmions. Their unique space-time topologies make them promising can…

physics.geo-ph2025

Exact Closed-form Solutions for Lamb's Problem

Xi Feng, Haiming Zhang

In this article, we report on an exact closed-form solution for the displacement at the surface of an elastic half-space elicited by a buried point source that acts at some point u…

quant-ph2017

Magnetic criticality-enhanced hybrid nanodiamond-thermometer under ambient conditions

Ning Wang, Gang-Qin Liu, Weng-Hang Leong +10

Nitrogen vacancy (NV) centres in diamond are attractive as quantum sensors owing to their superb coherence under ambient conditions. However, the NV centre spin resonances are rela…

math.GM2025

Metric Matrix in Barycentric Coordinates

Xi Feng

In this paper, the concept of the metric matrix is introduced to establish a concise and unified formulation for the inner product in barycentric coordinates. Building on this fram…

cs.CL2024

AutoPatent: A Multi-Agent Framework for Automatic Patent Generation

Qiyao Wang, Shiwen Ni, Huaren Liu +8

As the capabilities of Large Language Models (LLMs) continue to advance, the field of patent processing has garnered increased attention within the natural language processing comm…

physics.app-ph2026

Nanodiamond sensing in dynamic environments with fast-tracking through four-point positioning

Guoli Zhu, Ming-Zhong Ai, Zhiyu Zhao +8

Nitrogen-vacancy (NV) centers in nanodiamonds are excellent nanoscale sensors for measuring parameters such as temperature, magnetic field, and viscosity in complex fluidic environ…

quant-ph2018

Quantum coherence control at near 1000 K

Gang-Qin Liu, Xi Feng, Ning Wang +2

Quantum coherence control usually requires extremely low temperature environments. Even for spins in diamond, a remarkable exception, the coherence signal is lost as temperature ap…

math.MG2025

A Metric Framework for Triangle Inequalities via Barycentric Coordinates

Xi Feng

This paper presents a unified metric-based framework for triangle geometric inequalities using barycentric coordinates. By interpreting classical inequalities as squared distances…

cond-mat.mes-hall2021

Zero-field magnetometry using hyperfine-biased nitrogen-vacancy centers near diamond surfaces

Ning Wang, Chu-Feng Liu, Jing-Wei Fan +7

Shallow nitrogen-vacancy (NV) centers in diamond are promising for nano-magnetometry for they can be placed proximate to targets. To study the intrinsic magnetic properties, zero-f…

physics.geo-ph2025

Exact closed-form solutions for Lamb's problem (II): a moving point load

Xi Feng, Haiming Zhang

In this article, we report on an exact closed-form solution for the displacement in an elastic homogeneous half-space elicited by a downward vertical point source moving with const…

quant-ph2019

Ultra-sensitive hybrid diamond nanothermometer

Chu-Feng Liu, Weng-Hang Leong, Kangwei Xia +6

Nitrogen-vacancy (NV) centers in diamond are promising quantum sensors for their long spin coherence time under ambient conditions. However, their spin resonances are relatively in…

physics.optics2024

Photonic Terahertz Phased Array

Li Niu, Xi Feng, Xueqian Zhang +11

Phased arrays are crucial in various technologies, such as radar and wireless communications, due to their ability to precisely control and steer electromagnetic waves. This precis…

cs.CL2025

II-Bench: An Image Implication Understanding Benchmark for Multimodal Large Language Models

Ziqiang Liu, Feiteng Fang, Xi Feng +23

The rapid advancements in the development of multimodal large language models (MLLMs) have consistently led to new breakthroughs on various benchmarks. In response, numerous challe…

cs.RO2025

RoboBrain 2.0 Technical Report

BAAI RoboBrain Team, Mingyu Cao, Huajie Tan +50

We introduce RoboBrain 2.0, our latest generation of embodied vision-language foundation models, designed to unify perception, reasoning, and planning for complex embodied tasks in…

cs.AI2024

CLHA: A Simple yet Effective Contrastive Learning Framework for Human Alignment

Feiteng Fang, Liang Zhu, Min Yang +6

Reinforcement learning from human feedback (RLHF) is a crucial technique in aligning large language models (LLMs) with human preferences, ensuring these LLMs behave in beneficial a…

cond-mat.mes-hall2019

Nanometer-precision non-local deformation reconstruction using nanodiamond orientation sensing

Kangwei Xia, Chu-Feng Liu, Weng-Hang Leong +5

Information of material deformation upon loading is critical to evaluate mechanical properties of materials in general, and key to understand fundamental mechano-stimuli induced re…

physics.bio-ph2021

Measurement of single-cell elasticity by nanodiamond-sensing of non-local deformation

Yue Cui, Weng-Hang Leong, Chu-Feng Liu +5

Nano-indentation based on, e.g., atomic force microscopy (AFM), can measure single cell elasticity with high spatial resolution and sensitivity, but relating the data to cell mecha…

cs.CL2024

Can MLLMs Understand the Deep Implication Behind Chinese Images?

Chenhao Zhang, Xi Feng, Yuelin Bai +18

As the capabilities of Multimodal Large Language Models (MLLMs) continue to improve, the need for higher-order capability evaluation of MLLMs is increasing. However, there is a lac…