TY  - JOUR
AU  - Schwägerl, Tim
AU  - Jansen, Karl
AU  - Kühn, Stefan
TI  - Fermion discretization effects in the two-flavor lattice Schwinger model: A study with matrix product states
JO  - Physical review / D
VL  - 112
IS  - 9
SN  - 2470-0010
CY  - Ridge, NY
PB  - American Physical Society
M1  - PUBDB-2025-04068
M1  - arXiv:2509.02329
SP  - 094501
PY  - 2025
N1  - 23 pages, 11 figures
AB  - We present a comprehensive tensor network study of staggered, Wilson, and twisted mass fermions in the Hamiltonian formulation, using the massive two-flavor Schwinger model as a benchmark. Particular emphasis is placed on twisted mass fermions, whose properties in this context have not been systematically explored before. We confirm the expected O(a) improvement in the free theory and observe that this improvement persists in the interacting case. By leveraging an electric-field-based method for mass renormalization, we reliably tune to maximal twist and establish the method's applicability in the two-flavor model. Once mass renormalization is included, the pion mass exhibits rapid convergence to the continuum limit. Finite-volume effects are addressed using two complementary approaches: dispersion relation fits and finite-volume scaling. Our results show excellent agreement with semiclassical predictions and reveal a milder volume dependence for twisted mass fermions compared to staggered and Wilson discretizations. In addition, we observe clear isospin-breaking effects, suggesting intriguing parallels with lattice QCD. These findings highlight the advantages of twisted mass fermions for Hamiltonian simulations and motivate their further exploration, particularly in view of future applications to higher-dimensional lattice gauge theories.
LB  - PUB:(DE-HGF)16
DO  - DOI:10.1103/5kwl-8dhm
UR  - https://bib-pubdb1.desy.de/record/638440
ER  -