6 papers
Learning Dynamic Aperture from One-turn Maps
Derong Xu
Dynamic aperture evaluation relies on long-term tracking, while existing machine-learning surrogates remain difficult to generalize across machines. We demonstrate that coarse-grai…
Approximate Invariant Analysis: An Efficient Framework for Nonlinear Beam Dynamics, Part I: Geometric Approaches of the Poincaré Rotation Number
Yongjun Li, Sergei Nagaitsev, Derong Xu +2
We present the first part of an efficient framework for nonlinear beam dynamics, termed Approximate Invariant Analysis (AIA). The framework is based on the construction of approxim…
More Edits, More Stable: Understanding the Lifelong Normalization in Sequential Model Editing
Xin Ma, Wei Chen, Qi Liu +4
Lifelong Model Editing aims to continuously update evolving facts in Large Language Models while preserving unrelated knowledge and general capabilities, yet it remains plagued by…
Frequency Extraction from Invariant Flows
Derong Xu, Yongjun Li, Yue Hao +1
In non-degenerate integrable Hamiltonian systems, invariant tori can be parameterized equivalently by action variables or by their fundamental frequencies. We introduce an invarian…
Dynamic Focusing to Suppress Emittance Transfer in Crab-Crossing Flat Beam Collisions
Derong Xu, J Scott Berg, Michael M Blaskiewicz +8
Flat hadron beam collisions, though expected to enhance peak luminosity by about an order of magnitude, have not yet been demonstrated. Our study reveals a critical limitation: rea…
Beam Optics Ramping in Under-Constrained Lattice Design: Application to Electron-Ion Collider Hadron Storage Ring Cooling Section
Derong Xu
This paper presents the lattice design and optics ramping strategy for the cooling section of the Hadron Storage Ring (HSR) at the Electron-Ion Collider (EIC). The main challenge i…