Non-perturbative QCD Group

Welcome to the NpQCD Group at USTC

Strong Interaction, Hadronic Structure and Computational Physics

Exploring physics at the heart of matter

Research

Quantum chromodynamics (QCD) is the underlying theory of Strong Interaction. It describes the interactions between quarks and gluons. QCD is strongly coupled at low-enegy scale, which leads to remarkable non-perturbative physics, e.g. confinement and chiral symmetry breaking. The non-perturbative calculation of QCD is one of the most formidable challenges in Physics. It is also the key to answer some of the fundamental questions in Physics, such as how the quarks and gluons are bound together, and how the nuclear forces are formed to bind the nucleons. The non-perturbative properties of hadrons is also the focii of some present and forthcoming high-energy experiments, such as the electron-ion colliders (EICs) and the Super Tau-Charm Facilities (STCFs). For a comprehensive yet readable introduction to QCD, we recommend the following review: F. Gross and E. Klempt et. al., 50 Years of Quantum Chromodynamics, Eur. Phys. J. C 83, 1125 (2023).

The research of our group delves into the heart of the visible matter, the structures of the hadrons, such as the proton. We aim to understand how the non-perturbative structures of hadrons emerge from the quarks and gluons. To tackle these challenging issues, we employ a combination of theory, phenomenology and computation. One of our favorite approaches is the light-front Hamiltonian formalism. In this approach, the structures of the hadrons are fully described by the wave functions defined at on the light front \(x^+ \equiv ct+z = 0\). It is also closely related to the partonic structures of hadrons. Our ultimate goal is to develop an ab initio computational framework to solve for the light-front wave functions directly from the QCD Hamiltonian. For a review of light-front QCD, see Section 5.3 of the above review 50 years of QCD.

Specific topics of our group include:

Our Team

Yang Li

Yang Li is a professor of physics at the University of Science and Technology of China (USTC). He graduated from USTC in 2010. He obtained his Ph.D. at Iowa State University in 2015 under Prof. James Vary. He then worked at Iowa State University, the College of William & Mary and the University of the Chinese Academy of Sciences as postdocs and a lecturer. In 2021, he joined USTC as a professor. His primary research interests are Particle and High-Energy Nuclear Physics including non-perturbative QCD and hadronic structures. He received Gary McCartor Award by the International Light Cone Advisory Committee (ILCAC) in 2014. See his homepage and his inspire page for more information.

Contact: leeyoung1987\(@\)ustc.edu.cn

Xianghui Cao

Xianghui Cao is a graduate student at University of Science and Technology of China (USTC). He graduated from USTC in 2022 and subsequently joined Prof. Yang Li’s group. His research interests are non-perturbative quantum field theory and hadron physics.

Contact: xianghuicao\(@\)mail.ustc.edu.cn

Liuyuan Wen

Liuyuan Wen is currently a graduate student at the University of Science and Technology of China (USTC), pursuing a Master's degree in Physics under the supervision of Prof. Yang Li. He received his Bachelor's degree at Tianjin University in 2022 under Prof. Baoyi Chen. His research focuses on quarkonium in strong magnetic fields.

Contact: lywen\(@\)mail.ustc.edu.cn

Zhiguo Wang

Education:

  • 2018 - 2022, Lanzhou University, Bachelor
  • 2022 to present, University of Science and Technology of China, Master

Interests: quantum field theory, non-perturbative QCD, computational physics

Contact: wangzhg2022\(@\)mail.ustc.edu.cn

Yihan Duan

Yihan Duan is a graduate student at University of Science and Technology of China (USTC). He received his bachelor degree in physics from USTC in 2023 and subsequently joined Prof. Yang Li’s group. His research interests include non-perturbative QCD and nucleon structure.

Contact: dyh2019\(@\)mail.ustc.edu.cn

Wenyu Zhang

Wenyu Zhang is an undergraduate student at University of Science and Technology of China (USTC). He is expected to graduate in Fall of 2024 and join Prof. Yang Li's group. His research interests are non-perturbative quantum field theory, hadron physics and computational physics.

Contact: zwy_2020\(@\)mail.ustc.edu.cn

Tianyang Hu

Tianyang Hu is an undergraduate student at the University of Science and Technology of China (USTC). He is expected to graduate in Fall of 2024 and become a Ph.D. student at the Institute of Modern Physics, Chinese Academy of Sciences. His research interests are particle physics and non-perturbative QCD.

Contact: helloworldhty\(@\)mail.ustc.edu.cn

Qi'ao Li

Qi'ao Li is an undergraduate student at University of Science and Technologu of China (USTC). He is expected to graduate in 2025 and join Prof. Yang Li's group. His interests are particle physics and non-perturbative QCD.

Contact: frontal\(@\)mail.ustc.edu.cn

Recent Visitors

  • Guangyao Chen, Assistant Professor at Jacksonville University
  • Mengyao Huang, Postdoctoral Researcher at Lawrence Livermore National Laboratory
  • James Vary, Distinguished Professor at Iowa State University
  • Kamil Serafin, Postdoc at Institute of Modern Physics (present affiliation: Tufts University)
  • Weijie Du, Postdoc at Iowa State University

Alumni

  • Jialin Chen, undergraduate at Lanzhou University (present affiliation: Institute of Modern Physics)

Publications

Journal Articles (2021 - present)

  1. Siqi Xu*, Yiping Liu, Chandan Mondal, Jiangshan Lan, Xingbo Zhao, Yang Li, James P. Vary, Towards a first principles light-front Hamiltonian for the nucleon, [arXiv: 2408.11298 [hep-ph]]
  2. Tianyang Hu, Xianghui Cao, Siqi Xu, Yang Li*, Xingbo Zhao, James P. Vary, Gravitational form factor D of charmonium from shear stress, [arXiv: 2408.09689 [hep-ph]]
  3. Xianghui Cao, Yang Li*, James P. Vary, Dissecting a strongly coupled scalar nucleon, Phys. Rev. D 110, 076025 (2024); [arXiv: 2408.09535 [hep-ph]]
  4. Lingdi Meng, Shuo Tang, Zhi Hu*, Guo-Li Wang, Yang Li, Xingbo Zhao, James P. Vary, Electron form factors in Basis Light-front Quantization, [arXiv: 2405.16995 [hep-ph]]
  5. Yi Chen, Yang Li, Cédric Lorcé*, Qun Wang, The nucleon axial radius, [arXiv: 2405.12943 [hep-ph]]
  6. Xianghui Cao, Siqi Xu, Yang Li*, Guangyao Chen, Xingbo Zhao, V.A. Karmanov, James P. Vary, Energy momentum tensor on and off the light cone, JHEP 07 (2024) 095; [arXiv: 2405.06896 [hep-ph]]
  7. Yang Li*, Qun Wang, James P. Vary, Hadronic energy-momentum tensor revisited, [arXiv: 2405.06892 [hep-ph]]
  8. Yihan Duan, Siqi Xu, Shan Cheng, Xingbo Zhao, Yang Li*, James P. Vary, Flavor asymmetry from the non-perturbative nucleon sea, to appear in Phys. Rev. C; [arXiv: 2404.07755 [hep-ph]]
  9. Siqi Xu, Xianghui Cao, Tianyang Hu, Yang Li*, Xingbo Zhao, James P. Vary, Stress out of charmonia, Phys.Rev.D 109 (2024) 11, 114024; [arXiv: 2404.06259 [hep-ph]]
  10. Yang Li*, James Vary, Stress inside the pion in holographic light-front QCD, Phys. Rev. D 109, L051501 (2024); [arXiv:2312.02543 [hep-th]]
  11. Zhiguo Wang, Meijian Li*, Yang Li, James P. Vary, Shedding light on charmonium, Phys. Rev. D 109, L031902 (2024); [arXiv:2312.02604 [hep-ph]]
  12. Siqi Xu*, Chandan Mondal, Xingbo Zhao, Yang Li and James P. Vary, Quark and gluon spin and orbital angular momentum in the proton, Phys. Rev. D 108, 094002 (2023)
  13. Xianghui Cao, Yang Li*, James Vary, Forces inside a strongly-coupled scalar nucleon, Phys. Rev. D 108, 056026 (2023); [arXiv: 2308.06812 [hep-ph]]
  14. Siqi Xu*, Chandan Mondal, Xingbo Zhao, Yang Li, James P. Vary, Nucleon spin decomposition with one dynamical gluon, [arXiv: 2209.08584 [hep-ph]]
  15. Yang Li*, Wen-bo Dong, Yi-liang Yin, Qun Wang, James P. Vary, Minkowski's lost legacy and hadron electromagnetism, Phys. Lett. B 838 (2023) 137676; [arXiv: 2206.12903 [hep-ph]]
  16. Yang Li*, P. Maris, and J.P. Vary, Chiral sum rule on the light front, Phys. Lett. B 836 (2023) 137598; [arXiv: 2203.14447 [hep-th]]
  17. Yang Li*, and J.P. Vary, Longitudinal dynamics for mesons on the light cone, Phys. Rev. D 105, 114006 (2022); [arXiv: 2202.05581 [hep-ph]]
  18. Yang Li, Meijian Li*, and J.P. Vary, Two-photon transitions of charmonia on the light front, Phys. Rev. D 105 (2022) 7, L071901; [arXiv: 2111.14178 [hep-ph]]
  19. Meijian Li, Yang Li*, Guangyao Chen, T. Lappi, and J.P. Vary, Light-front wavefunctions of mesons by design, Eur. Phys. J. C 82 (2022) 11; [arXiv: 2111.07087 [hep-ph]]
  20. Siqi Xu* et al. (BLFQ Collaboration), Nucleon structure from basis light-front quantization, Phys. Rev. D 104 (2021) 9, 094036; [arXiv: 2108.03909 [hep-ph]]
  21. Yang Li*, and J.P. Vary, Light-front holography with chiral symmetry breaking, Phys. Lett. B 825 (2022) 136860; [arXiv:2103.09993 [hep-ph]]
* Corresponding authors

Reviews and Chapters

  1. James P. Vary, Yang Li, Chandan Mondal and Xingbo Zhao, Light-front quantization, in 50 Years of Quantum Chromodynamics, F. Gross and E. Klempt Eds., Eur. Phys. J. C 83, 1125 (2023)

Talks

Conferences

Seminars

Events