English

Structure of QC$_2$D ground state fields at nonzero matter densities

High Energy Physics - Lattice 2026-03-25 v1 High Energy Physics - Phenomenology Nuclear Theory

Abstract

A quantitative investigation into the modification of ground-state field structures in two-color QCD (QC2_2D) is presented at finite chemical potential. Using lattice simulations with Wilson gauge and fermion actions, we explore the chromo-electromagnetic field strengths under varying matter densities. To ensure accurate measurements, we develop and calibrate two highly improved topological charge operators and evaluate four gradient flow actions. Our results reveal a finite-volume crossover in the regime of the anticipated phase boundary at μ=mπ/2\mu = m_\pi/2, with both chromo-electric and chromo-magnetic field strengths suppressed before recovering and exceeding vacuum values at higher chemical potentials. We find the difference between the squared chromo-electric and chromo-magnetic field strengths, E2B2E^2-B^2, to increase in magnitude monotonically with increasing chemical potential. At aμ=0.7a\mu=0.7, we find an 11%11\% suppression of E2E^2, a relatively small effect. A systematic analysis using sigmoid fits of lattice simulations in the crossover regime is performed to confirm the critical chemical potential obtained from the field structure is in agreement with the phase boundary at mπ/2m_\pi / 2. These findings provide new insight into non-Abelian ground-state vacuum field structures and offer a foundation for future studies in real QCD.

Keywords

Cite

@article{arxiv.2603.22825,
  title  = {Structure of QC$_2$D ground state fields at nonzero matter densities},
  author = {Ragib F. Hasan and Matthew Cummins and Waseem Kamleh and Dale Lawlor and Derek Leinweber and Ian van Schalkwyk and Jon-Ivar Skullerud},
  journal= {arXiv preprint arXiv:2603.22825},
  year   = {2026}
}

Comments

18 pages, 13 figures

R2 v1 2026-07-01T11:34:51.388Z