Tu Guo / 郭图@归途如稽

Tu Guo / 郭图@归途如稽

SJTU/TDLI Undergraduate

Posts by Collection

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.

Download Paper

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

Published in The Astrophysical Journal, 2025

Abstract: We present a general semi-analytical framework for analyzing energy-dependent soft X-ray polarization signature from magnetars, which consistently incorporates both QED vacuum resonance and resonant Compton scattering (RCS) effect. Starting from the polarized radiative transfer equation for RCS, we include mode conversion induced by vacuum resonance as an input; under a first-order approximation in optical depth (valid when τ ≲ 1), we evaluate the influence of magnetic twist (or plasma density), drift velocity of magnetospheric plasma, magnetospheric temperature, and viewing geometry on observed spectrum and polarization. The main results are: (i) magnetic twist (plasma density) and drift velocity are the key parameters controlling RCS re-procession on both the absolute polarization degree and its energy variance in soft X-ray radiation; (ii) in addition to QED, apparent special-relativistic effects (where plasma drift velocity β0 ≳ 0.5) in the scattering process may introduce an extra 90◦ polarization angle (PA) swing in the spectrum; (iii) single RCS has minimal effect on the energy where the initial QED-induced PA swing occurs; (iv) strong RCS (even single scattering) may wash out the PA swing caused by vacuum resonance. This framework offers a new concise paradigm without resorting to complex multidimensional Monte Carlo radiative transfer simulations, and provides a potential pathway toward the analytical treatment of full-surface emission and rotational-phase-resolved modeling of magnetar radiation to support future X-ray polarization missions.

Download Paper

Nature/Nature Machine Intelligence: PhysMaster: Building an Autonomous AI Physicist for Theoretical and Computational Physics Research

Published in Nature/Nature Machine Intelligence, 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.

Download Paper

talks