Chen Zhao
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2026
Beyond Single-shot Writing: Deep Research Agents are Unreliable at Multi-turn Report Revision
Bingsen Chen | Boyan Li | Ping Nie | Yuyu Zhang | Xi Ye | Chen Zhao
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Bingsen Chen | Boyan Li | Ping Nie | Yuyu Zhang | Xi Ye | Chen Zhao
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Existing benchmarks for Deep Research Agents (DRAs) treat report generation as a single-shot writing task, which fundamentally diverges from how human researchers iteratively draft and revise reports via self-reflection or peer feedback. Whether DRAs can reliably revise reports with user feedback remains unexplored. We introduce Mr Dre, an evaluation suite that establishes multi-turn report revision as a new axis. Mr Dre consists of (1) a unified long-form report evaluation protocol spanning comprehensiveness, factuality, and presentation, and (2) a human-verified feedback simulation pipeline for systematic multi-turn revision evaluation. Our analysis of five diverse DRAs reveals a critical limitation: while agents can address most user feedback, they also regress on 16–27% of previously covered content and citation quality. Over multiple revision turns, even the best-performing agents leave significant headroom, as they continue to disrupt content outside the feedback’s scope and fail to preserve earlier edits. We further show that these issues are not easily resolvable through inference-time fixes such as prompt engineering and a dedicated sub-agent for revision.
A Survey of Multimodal Mathematical Reasoning: From Perception, Alignment to Reasoning
Tianyu Yang | Sihong Wu | Yilun Zhao | Zhenwen Liang | Lisen Dai | Chen Zhao | Minhao Cheng | Arman Cohan | Xiangliang Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Tianyu Yang | Sihong Wu | Yilun Zhao | Zhenwen Liang | Lisen Dai | Chen Zhao | Minhao Cheng | Arman Cohan | Xiangliang Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Multimodal Mathematical Reasoning (MMR) has recently attracted increasing attention for its capability to solve mathematical problems involving both textual and visual modalities. However, current models still face significant challenges in real-world visual math tasks, often misinterpreting diagrams, failing to align mathematical symbols with visual evidence, or producing inconsistent reasoning steps. Moreover, existing evaluations mainly focus on checking final answers rather than verifying the correctness or executability of each intermediate step. A growing body of recent research addresses these issues by integrating structured perception, explicit alignment, and verifiable reasoning within unified frameworks.To establish a clear roadmap for understanding and comparing different MMR approaches, we systematically review them around four fundamental questions: (1) What to extract from multimodal inputs, (2) How to represent and align textual and visual information, (3) How to perform the reasoning, and (4) How to evaluate the correctness of the overall reasoning process. Finally, we discuss open challenges and share our thoughts on future research directions.
Rethinking Reasoning-Intensive Retrieval: Evaluating and Advancing Retrievers in Agentic Search Systems
Yilun Zhao | Jinbiao Wei | Tingyu Song | Siyue Zhang | Chen Zhao | Arman Cohan
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yilun Zhao | Jinbiao Wei | Tingyu Song | Siyue Zhang | Chen Zhao | Arman Cohan
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Reasoning-intensive retrieval aims to surface evidence that maximizes downstream reasoning utility rather than only topical similarity. This capability is increasingly vital for agentic retriever-in-the-loop systems such as Deep-Research. However, existing retriever evaluation benchmarks, exemplified by Bright, provide narrow gold sets and evaluate retrievers in isolation, which obscures their value inside realistic agent workflows. We introduce Bright-Pro, an evaluation framework that assesses the effectiveness of retrievers in agentic search systems. Bright-Pro covers a broad range of queries across diverse professional domains. For each query, we provide expert-annotated reasoning aspects, positive documents, a reference response, and evaluation rubrics, enabling fine-grained assessment of retriever performance. Beyond static evaluation, we further assess retrievers in the context of agentic search systems, measuring their practical utility when serving as core components within agentic workflows. Using Bright-Pro, we evaluate classical lexical, general-purpose, and reasoning-intensive retrievers, providing actionable insights for future retriever development.
2025
Are Multimodal LLMs Robust Against Adversarial Perturbations? RoMMath: A Systematic Evaluation on Multimodal Math Reasoning
Yilun Zhao | Guo Gan | Chengye Wang | Chen Zhao | Arman Cohan
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Yilun Zhao | Guo Gan | Chengye Wang | Chen Zhao | Arman Cohan
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
We introduce RoMMath, the first benchmark designed to evaluate the capabilities and robustness of multimodal large language models (MLLMs) in handling multimodal math reasoning, particularly when faced with adversarial perturbations. RoMMath consists of 4,800 expert-annotated examples, including an original set and seven adversarial sets, each targeting a specific type of perturbation at the text or vision levels. We evaluate a broad spectrum of 17 MLLMs on RoMMath and uncover a critical challenge regarding model robustness against adversarial perturbations. Through detailed error analysis by human experts, we gain a deeper understanding of the current limitations of MLLMs. Additionally, we explore various approaches to enhance the performance and robustness of MLLMs, providing insights that can guide future research efforts.
FinLFQA: Evaluating Attributed Text Generation of LLMs in Financial Long-Form Question Answering
Yitao Long | Tiansheng Hu | Yilun Zhao | Arman Cohan | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Yitao Long | Tiansheng Hu | Yilun Zhao | Arman Cohan | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Large Language Models (LLMs) frequently hallucinate to long-form questions, producing plausible yet factually incorrect answers. A common mitigation strategy is to provide attribution to LLM outputs. However, existing benchmarks primarily focus on simple attribution that retrieves supporting textual evidence as references. We argue that in real-world scenarios such as financial applications, attribution goes beyond reference retrieval.We introduce FinLFQA, a benchmark designed to evaluate the ability of LLMs to generate long-form answers to complex financial questions with reliable and nuanced attributions. FinLFQA evaluates three critical aspects of attribution through human annotations: (1) supporting evidence extracted from financial reports, (2) intermediate numerical reasoning steps, and (3) domain-specific financial knowledge that informs the reasoning process.We further provide an automatic evaluation framework covering both answer quality and attribution quality. Through extensive experiments on eight LLMs across multiple attribution-generation paradigms, we find that fine-grained metrics are important to distinguish model capabilities, that end-to-end generation achieves comparable performance to post-hoc approaches, and that iterative refinement only helps when guided by external feedback.
MCTS-RAG: Enhancing Retrieval-Augmented Generation with Monte Carlo Tree Search
Yunhai Hu | Yilun Zhao | Chen Zhao | Arman Cohan
Findings of the Association for Computational Linguistics: EMNLP 2025
Yunhai Hu | Yilun Zhao | Chen Zhao | Arman Cohan
Findings of the Association for Computational Linguistics: EMNLP 2025
We introduce MCTS-RAG, a novel approach that enhances the reasoning capabilities of small language models on knowledge-intensive tasks by leveraging retrieval-augmented generation (RAG) to provide relevant context and Monte Carlo Tree Search (MCTS) to refine reasoning paths. MCTS-RAG dynamically integrates retrieval and reasoning through an iterative decision-making process. Unlike standard RAG methods, which typically retrieve information independently from reasoning and thus integrate knowledge suboptimally, or conventional MCTS reasoning, which depends solely on internal model knowledge without external facts, MCTS-RAG combines structured reasoning with adaptive retrieval. This integrated approach enhances decision-making, reduces hallucinations, and ensures improved factual accuracy and response consistency. The experimental results on multiple reasoning and knowledge-intensive datasets datasets (ComplexWebQA, GPQA, and FoolMeTwice) show that our method enables small-scale LMs to achieve performance comparable to frontier LLMs like GPT-4o by effectively scaling inference-time compute, setting a new standard for reasoning in small-scale models.
MRAG: A Modular Retrieval Framework for Time-Sensitive Question Answering
Siyue Zhang | Yuxiang Xue | Yiming Zhang | Xiaobao Wu | Anh Tuan Luu | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Siyue Zhang | Yuxiang Xue | Yiming Zhang | Xiaobao Wu | Anh Tuan Luu | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Understanding temporal concepts and answering time-sensitive questions is crucial yet a challenging task for question-answering systems powered by large language models (LLMs). Existing approaches either update the parametric knowledge of LLMs with new facts, which is resource-intensive and often impractical, or integrate LLMs with external knowledge retrieval (i.e., retrieval-augmented generation). However, off-the-shelf retrievers often struggle to identify relevant documents that require intensive temporal reasoning. To systematically study time-sensitive question answering, we introduce the TempRAGEval benchmark, which repurposes existing datasets by incorporating complex temporal perturbations and gold evidence labels. As anticipated, all existing retrieval methods struggle with these temporal reasoning-intensive questions. We further propose Modular Retrieval (MRAG), a trainless framework that includes three modules: (1) Question Processing that decomposes question into a main content and a temporal constraint; (2) Retrieval and Summarization that retrieves, splits, and summarize evidence passages based on the main content; (3) Semantic-Temporal Hybrid Ranking that scores semantic and temporal relevance separately for each fine-grained evidence. On TempRAGEval, MRAG significantly outperforms baseline retrievers in retrieval performance, leading to further improvements in final answer accuracy.
Physics: Benchmarking Foundation Models on University-Level Physics Problem Solving
Kaiyue Feng | Yilun Zhao | Yixin Liu | Tianyu Yang | Chen Zhao | John Sous | Arman Cohan
Findings of the Association for Computational Linguistics: ACL 2025
Kaiyue Feng | Yilun Zhao | Yixin Liu | Tianyu Yang | Chen Zhao | John Sous | Arman Cohan
Findings of the Association for Computational Linguistics: ACL 2025
We introduce Physics, a comprehensive benchmark for university-level physics problem solving. It contains 1,297 expert-annotated problems covering six core areas: classical mechanics, quantum mechanics, thermodynamics and statistical mechanics, electromagnetism, atomic physics, and optics.Each problem requires advanced physics knowledge and mathematical reasoning.We develop a robust automated evaluation system for precise and reliable validation. Our evaluation of leading foundation models reveals substantial limitations. Even the most advanced model, o3-mini, achieves only 59.9% accuracy, highlighting significant challenges in solving high-level scientific problems.Through comprehensive error analysis, exploration of diverse prompting strategies, and Retrieval-Augmented Generation (RAG)-based knowledge augmentation, we identify key areas for improvement, laying the foundation for future advancements.
Inter-Passage Verification for Multi-evidence Multi-answer QA
Bingsen Chen | Shenji Wan | Xi Ye | Chen Zhao
Findings of the Association for Computational Linguistics: ACL 2025
Bingsen Chen | Shenji Wan | Xi Ye | Chen Zhao
Findings of the Association for Computational Linguistics: ACL 2025
Multi-answer question answering (QA), where questions can have many valid answers, presents a significant challenge for existing retrieval-augmented generation-based QA systems, as these systems struggle to retrieve and then synthesize a large number of evidence passages. To tackle these challenges, we propose a new multi-answer QA framework – Retrieval-augmented Independent Reading with Inter-passage Verification (RI²VER). Our framework retrieves a large set of passages and processes each passage individually to generate an initial high-recall but noisy answer set. Then we propose a new inter-passage verification pipeline that validates every candidate answer through (1) Verification Question Generation, (2) Gathering Additional Evidence, and (3) Verification with inter-passage synthesis. Evaluations on the QAMPARI and RoMQA datasets demonstrate that our framework significantly outperforms existing baselines across various model sizes, achieving an average F1 score improvement of 11.17%. Further analysis validates that our inter-passage verification pipeline enables our framework to be particularly beneficial for questions requiring multi-evidence synthesis.
FinTrust: A Comprehensive Benchmark of Trustworthiness Evaluation in Finance Domain
Tiansheng Hu | Tongyan Hu | Liuyang Bai | Yilun Zhao | Arman Cohan | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Tiansheng Hu | Tongyan Hu | Liuyang Bai | Yilun Zhao | Arman Cohan | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Recent LLMs have demonstrated promising ability in solving finance related problems. However, applying LLMs in real-world finance application remains challenging due to its high risk and high stakes property. This paper introduces FinTrust, a comprehensive benchmark specifically designed for evaluating the trustworthiness of LLMs in finance applications. Our benchmark focuses on a wide range of alignment issues based on practical context and features fine-grained tasks for each dimension of trustworthiness evaluation. We assess eleven LLMs on FinTrust and find that proprietary models like o4-mini outperforms in most tasks such as safety while open-source models like DeepSeek-V3 have advantage in specific areas like industry-level fairness. For challenging task like fiduciary alignment and disclosure, all LLMs fall short, showing a significant gap in legal awareness. We believe that FinTrust can be a valuable benchmark for LLMs’ trustworthiness evaluation in finance domain.
SportReason: Evaluating Retrieval-Augmented Reasoning across Tables and Text for Sports Question Answering
Kaiyue Feng | Siyue Zhang | Bingsen Chen | Yilun Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Kaiyue Feng | Siyue Zhang | Bingsen Chen | Yilun Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
We present SportReason, a benchmark for retrieval-augmented reasoning on numerical sports questions. Unlike existing benchmarks limited to one or two evidence units, SportReason requires combining and reasoning across free-text, structured tables, and semi-structured infoboxes. We provide 3,000 human-verified QA pairs by repurposing existing QA and table generation datasets, and by prompting large language models (LLMs). Each pair is grounded in multiple evidence from a multi-modal Wikipedia corpus containing 200K knowledge contexts. We evaluate existing retrievers and rerankers, along with agentic Retrieval-Augmented Generation (RAG) systems. The experimental results show that multi-evidence retrieval remains a challenge. Agentic RAG systems (e.g., Search-o1), despite iterative retrieval and reasoning capabilities, fail to improve performance due to imprecise queries, simple training, and distracting information.
Diffusion vs. Autoregressive Language Models: A Text Embedding Perspective
Siyue Zhang | Yilun Zhao | Liyuan Geng | Arman Cohan | Anh Tuan Luu | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Siyue Zhang | Yilun Zhao | Liyuan Geng | Arman Cohan | Anh Tuan Luu | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Large language model (LLM)-based embedding models, benefiting from large scale pre-training and post-training, have begun to surpass BERT and T5-based models on general-purpose text embedding tasks such as document retrieval. However, a fundamental limitation of LLM embeddings lies in the unidirectional attention used during autoregressive pre-training, which misaligns with the bidirectional nature of text embedding tasks. To this end, We propose adopting diffusion language models for text embeddings, motivated by their inherent bidirectional architecture and recent success in matching or surpassing LLMs especially on reasoning tasks. We present the first systematic study of the diffusion language embedding model, which outperforms the LLM-based embedding model by 20% on long-document retrieval, 8% on reasoning-intensive retrieval, 2% on instruction-following retrieval, and achieve competitive performance on traditional text embedding benchmarks. Our analysis verifies that bidirectional attention is crucial for encoding global context in long and complex text.
RPDR: A Round-trip Prediction-Based Data Augmentation Framework for Long-Tail Question Answering
Yiming Zhang | Siyue Zhang | Junbo Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Yiming Zhang | Siyue Zhang | Junbo Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Long-tail question answering presents significant challenges for large language models (LLMs) due to their limited ability to acquire and accurately recall less common knowledge. Retrieval-augmented generation (RAG) systems have shown great promise in mitigating this limitation by integrating external retrieval mechanisms. However, dense retrieval models often face the same difficulties when generalizing to rare or niche knowledge. In this study, we introduce RPDR, a novel data augmentation framework that selects high-quality easy-to-learn training data, to enhance dense retrievers. Our approach is built around three core components: synthetic data generation, data selection with Round-Trip prediction to identify easy-to-learn instances, and retriever training with these instances. We evaluate RPDR on two long-tail retrieval benchmarks, PopQA and EntityQuestion, demonstrating substantial improvements over existing retrievers like BM25 and Contriver, especially on extremely long-tail categories. We identify the strengths and limitations of RPDR through detailed human analysis and propose a dynamic routing mechanism to dynamically route queries to specialized retrieval modules to further improve retrieval performance.
LimRank: Less is More for Reasoning-Intensive Information Reranking
Tingyu Song | Yilun Zhao | Siyue Zhang | Chen Zhao | Arman Cohan
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Tingyu Song | Yilun Zhao | Siyue Zhang | Chen Zhao | Arman Cohan
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Existing approaches typically rely on large-scale fine-tuning to adapt LLMs for information reranking tasks, which is computationally expensive. In this work, we demonstrate that modern LLMs can be effectively adapted using only minimal, high-quality supervision. To enable this, we design LIMRANK-SYNTHESIZER, a reusable and open-source pipeline for generating diverse, challenging, and realistic reranking examples. Using this synthetic data, we fine-tune our reranker model, LIMRANK. We evaluate LIMRANK on two challenging benchmarks, i.e., BRIGHT for reasoning-intensive retrieval and FollowIR for instruction-following retrieval. Our experiments demonstrate that LIMRANK achieves competitive performance, while being trained on less than 5% of the data typically used in prior work. Further ablation studies demonstrate the effectiveness of LIMRANK-SYNTHESIZER and the strong generalization capabilities of LIMRANK across downstream tasks, including scientific literature search and retrieval-augmented generation for knowledge-intensive problem solving.
SciSketch: An Open-source Framework for Automated Schematic Diagram Generation in Scientific Papers
Zihang Wang | Yilun Zhao | Kaiyan Zhang | Chen Zhao | Manasi Patwardhan | Arman Cohan
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Zihang Wang | Yilun Zhao | Kaiyan Zhang | Chen Zhao | Manasi Patwardhan | Arman Cohan
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
High-quality schematic diagrams, which provide a conceptual overview of the research, play a crucial role in summarizing and clarifying a study’s core ideas. However, creating these diagrams is time-consuming for authors and remains challenging for current AI systems, as it requires both a deep understanding of the paper’s content and a strong sense of visual design. To address this, we introduce SCISKETCH, an open-source framework that supports two automated workflows for schematic diagram generation using foundation models, shown in Figure 1. 1) In the graphic-code-based workflow, SCISKETCH follows a two-stage pipeline: it first produces a layout plan expressed in a graphical code language with a self-refinement and self-verification mechanism. It then integrates empirical images and symbolic icons to create a visually coherent, informative diagram. 2) In the image-based workflow, SCISKETCH directly synthesizes the diagram image through image generation with a self-refinement mechanism. Through both automatic and human evaluations, we show that SCISKETCH outperforms several state-of-the-art foundation models, including GPT-4o, and Gemini-2.5-Pro, in generating schematic diagrams for scientific papers. We make SCISKETCH fully open-sourced, providing researchers with an accessible, extensible tool for high-quality schematic diagram generation in scientific fields.
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- Yilun Zhao 11
- Arman Cohan 10
- Siyue Zhang 6
- Bingsen Chen 3
- Kaiyue Feng 2
- Tiansheng Hu 2
- Tingyu Song 2
- Luu Anh Tuan 2
- Tianyu Yang 2
- Xi Ye 2
- Yiming Zhang 2
- Liuyang Bai 1
- Minhao Cheng 1
- Lisen Dai 1
- Guo Gan 1
- Liyuan Geng 1
- Tongyan Hu 1
- Yunhai Hu 1
- Boyan Li 1
- Zhenwen Liang 1
- Yixin Liu 1
- Yitao Long 1
- Ping Nie 1
- Manasi Patwardhan 1
- John Sous 1
- Shenji Wan 1
- Chengye Wang 1
- Zihang Wang 1
- Jinbiao Wei 1
- Sihong Wu 1
- Xiaobao Wu 1
- Yuxiang Xue 1
- Kaiyan Zhang 1
- Xiangliang Zhang 1
- Yuyu Zhang 1
- Junbo Zhao 1