Eur. Phys. J. Spec. Top.
https://doi.org/10.1140/epjs/s11734-025-02084-y

Review

Nucleon structure from basis light-front quantization: status and prospects

¹ Department of Physics and Astronomy, Iowa State University, 50011, Ames, IA, USA
² Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, Gansu, China
³ School of Nuclear Physics, University of Chinese Academy of Sciences, 100049, Beijing, China
⁴ CAS Key Laboratory of High Precision Nuclear Spectroscopy, Institute of Modern Physics, Chinese Academy of Sciences, 730000, Lanzhou, Gansu, China
⁵ Advanced Energy Science and Technology, Guangdong Laboratory, 516000, Guangdong, China
⁶ University of Science and Technology of China, 230026, Hefei, Anhui, China
⁷ Anhui Center for Fundamental Sciences in Theoretical Physics, University of Science and Technology of China, 230026, Hefei, China

^a This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 3 September 2025
Accepted: 25 November 2025
Published online: 13 December 2025

Abstract

We review recent advancements in understanding nucleon structure within the Basis Light-Front Quantization (BLFQ) framework—a fully relativistic, nonperturbative approach to solving quantum field theories. In its initial phase, we start with the leading Fock sector $|qqq⟩$ and an effective light-front Hamiltonian incorporating confinement and one-gluon exchange within which BLFQ can already successfully describe key nucleon observables. The framework has since been extended to include the next-to-leading Fock sector $|qqqg⟩$, enabling studies of gluonic contributions to the nucleon’s internal structure, including gluon helicity, orbital angular momentum, and three-dimensional imaging through generalized and transverse momentum dependent parton distributions (GPDs and TMDs). Most recently, BLFQ has achieved a significant milestone by computing nucleon light-front wavefunctions as eigenstates of the QCD Hamiltonian without an explicit confining potential. These calculations, including Fock sectors up to $|qqqq\overline{q}⟩$, further develop the path to first-principles predictions of quark and gluon matter densities, helicity and transversity distributions, and spin observables, showing qualitative agreement with experimental and phenomenological results. Together, these developments highlight BLFQ’s growing capacity to provide an increasingly complete and realistic picture of nucleon structure grounded in QCD.