Tu Guo (郭图)

Tu Guo (郭图)

SJTU/TDLI Ph.D student

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publications

PRD: Power corrections in the determination of heavy meson LCDAs: A renormalon-based estimation

Published in Physical Review D, 2025

Abstract: At leading power accuracy the QCD light-cone distribution amplitudes (LCDAs) for a heavy meson can be matched onto the LCDAs in the framework of heavy-quark effective theory (HQET) through a factorization formula. We examine the power corrections to this factorization in the renormalon model, which can associate the power corrections originating from high-twist contributions to the divergent series in a matching kernel. Our analysis indicates that the dominant power corrections originate from the virtual part of the vertex bubble chain diagrams, which generate poles at w=n+12,∀n∈ℕ and w=1 in the Borel plane. Employing phenomenological models for both HQET and QCD LCDA, we present a numerical estimate. The results indicate that the power corrections in the peak region are approximately 22% for the D meson and 7% for the B–meson. These findings showcase the magnitude and the potential importance of power corrections in achieving high-precision phenomenological predictions for heavy mesons.

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ApJ: Impact of Resonant Compton Scattering on Magnetar X-Ray Polarization with QED Vacuum Resonance

Published in The Astrophysical Journal, 2025

Abstract: Recent obeservations have revealed significant soft X-ray polarizations from several quiescent magnetars, including the intriguing 90∘ polarization angle (PA) swing as a function of photon energy for some sources. We present a general semi-analytical framework for calculating energy-dependent soft X-ray polarization signatures from magnetars, consistently incorporating both QED vacuum resonance in the atmosphere and resonant Compton scattering (RCS) in the magnetosphere. Starting from the polarized radiative transfer equation for RCS and treating vacuum-resonance-induced mode conversion as an input, we employ a first-order approximation in RCS optical depth to evaluate the effect of different magnetospheric plasma density (which depends on magnetic twist), drift velocity and temperature, and viewing geometry on the observed radiation. Our analysis reveals that magnetic twist and plasma drift velocity are the critical parameters controlling the impact of RCS on both the absolute polarization degree and its variation across the soft X-ray spectrum. We find that sufficiently strong RCS can wash out the PA swing caused by vacuum resonance. Furthermore, in addition to the QED vacuum resonance effect, significant relativistic signatures arising from plasma drift velocity (β0≳0.5) may introduce an extra 90∘ PA swing in the spectrum. Our calculation framework, based on single-scattering approximation, bypasses the need for complex, multi-dimensional Monte Carlo simulations, providing an analytical pathway for modeling full-surface emission and rotational-phase-resolved radiation from magnetic neutron stars, in support of current and future X-ray polarization missions.

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ICML 2026 AI4Physics Workshop: PhysMaster: Building an Autonomous AI Physicist for Theoretical and Computational Physics Research

Published in ICML 2026, 2025

Abstract: Advances in LLMs have produced agents with knowledge and operational capabilities comparable to human scientists, suggesting potential to assist, accelerate, and automate research. However, existing studies mainly evaluate such systems on well-defined benchmarks or general tasks like literature retrieval, limiting their end-to-end problem-solving ability in open scientific scenarios. This is particularly true in physics, which is abstract, mathematically intensive, and requires integrating analytical reasoning with code-based computation. To address this, we propose PhysMaster, an LLM-based agent functioning as an autonomous theoretical and computational physicist. PhysMaster couples absract reasoning with numerical computation and leverages LANDAU, the Layered Academic Data Universe, which preserves retrieved literature, curated prior knowledge, and validated methodological traces, enhancing decision reliability and stability. It also employs an adaptive exploration strategy balancing efficiency and open-ended exploration, enabling robust performance in ultra-long-horizon tasks. We evaluate PhysMaster on problems from high-energy theory, condensed matter theory to astrophysics, including: (i) acceleration, compressing labor-intensive research from months to hours; (ii) automation, autonomously executing hypothesis-driven loops ; and (iii) autonomous discovery, independently exploring open problems.

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ICML 2026 AI4Physics Workshop: PRL-Bench: A Comprehensive Benchmark Evaluating LLMs’ Capabilities in Frontier Physics Research

Published in ICML 2026 AI4Physics Workshop, 2026

Abstract: The paradigm of agentic science requires AI systems to conduct robust reasoning and engage in long-horizon, autonomous exploration. However, current scientific benchmarks remain confined to domain knowledge comprehension and complex reasoning, failing to evaluate the exploratory nature and procedural complexity of real-world research. In this work, we present research-oriented evaluations in theoretical and computational physics, a natural testbed with comprehensive domain knowledge, complex reasoning, and verifiable end-to-end workflows without reliance on experiments. Here we introduce PRL-Bench (Physics Research by LLMs), a benchmark designed to systematically map the capability boundaries of LLMs in executing end-to-end physics research. Constructed from 100 curated papers from the latest issues of Physical Review Letters since August 2025 and validated by domain experts, PRL-Bench covers five major theory- and computation-intensive subfields of modern physics: astrophysics, condensed matter physics, high-energy physics, quantum information, and statistical physics. Each task in the benchmark is designed to replicate the core properties of authentic scientific research, including exploration-oriented formulation, long-horizon workflows, and objective verifiability, thereby reconstructing the essential reasoning processes and research workflows of real physics research. Evaluation across frontier models shows that performance remains limited, with the best overall score below 50, revealing a pronounced gap between current LLM capabilities and the demands of real scientific research. PRL-Bench serves a reliable testbed for accessing next generation AI scientists advancing AI systems toward autonomous scientific discovery.

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ApJ: Beyond Cassini States: Analytical Framework for Non-Trivial Obliquity Steady States in Multi-Planetary Super-Earth Systems

Published in The Astrophysical Paper, 2026

Abstract: (Current version in prep) We develop an analytical theory for tidally dissipative spin evolution in compact multi-planet superEarth systems, and identify the dynamical origin of a class of high-obliquity spin steady states beyond classical Cassini states. Previous numerical studies have revealed such “non-trivial” steady states, but their underlying mechanism remained unclear. Starting from the spin Hamiltonian in a precessing orbital frame, we treat the second outer companion as a periodic perturbation to Colombo’s Top and incorporate tides as a non-Hamiltonian dissipative term. We demonstrate that the non-trivial steady states correspond to stable dissipative limit cycles in a weakly-dissipative nearly-integrable spin system. Their locations in phase space are determined by nonlinear m : n resonances between the intrinsic libration or circulation frequency of the spin and the companion-induced driving frequency. A resonant attractor forms when perturbative driving balances tidal dissipation over one geometric recurrence cycle, while phase locking fixes the relative phase between the spin motion and the external forcing. This framework accounts for the coexistence of libration and circulation attractors, the rational relation gres = (m/n)∆g, the emergence of multiple higher-order resonant branches, and the requirement that such branches survive only under suffciently weak tidal damping. The existence condition for tidal strength is compatible with realistic close-in super-Earth parameters and explains why previous simulations adopting stronger dissipation may miss these structures. Our results suggest that high obliquity can be a generic dissipative end state of multi-planet spin dynamics, rather than an outcome limited to classical Cassini-state evolution.

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BS thesis released

Published:

For those who are interested with my BS thesis, click the link below…