Tensor network simulations of quasi-GPDs in the massive Schwinger model

Journal Article · Tue Apr 14 00:00:00 UTC 2026 · Physical Review. D.

DOI: https://doi.org/10.1103/sz3z-8cyx · OSTI ID:3364091

Grieninger, Sebastian  ^[1]; Montgomery, Jake  ^[2]; Ringer, Felix  ^[2]; Zahed, Ismail ^[2]

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1. Univ. of Washington, Seattle, WA (United States); Stony Brook Univ., NY (United States)
2. Stony Brook Univ., NY (United States)

Generalized parton distribution functions (GPDs) are off-diagonal light-cone matrix elements that encode the internal structure of hadrons in terms of quark and gluon degrees of freedom. In this work, we present the first nonperturbative study of quasi-GPDs in the massive Schwinger model, quantum electrodynamics in 1+1 dimensions (QED₂), within the Hamiltonian formulation of lattice field theory. Quasidistributions are spatial correlation functions of boosted states, which approach the relevant light-cone distributions in the luminal limit. Using tensor networks, we prepare the first excited state in the strongly coupled regime and boost it to close to the light-cone on lattices of up to 400 lattice sites. We compute both quasiparton distribution functions and, for the first time, quasi-GPDs, and study their convergence for increasingly boosted states. In addition, we perform analytic calculations of GPDs in the two-particle Fock-space approximation and in the Reggeized limit, providing qualitative benchmarks for the tensor network results. Our analysis establishes computational benchmarks for accessing partonic observables in low-dimensional gauge theories, offering a starting point for future extensions to higher dimensions, non-Abelian theories, and quantum simulations.

• Research Organization: Univ. of Washington, Seattle, WA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Nuclear Physics (NP)
• Grant/Contract Number: FG02-97ER41014; SC0012704; SC0020970; SC0023646; SC0025881
• OSTI ID: 3364091
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 7 Vol. 113; ISSN 2470-0010; ISSN 2470-0029
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English