PaperPanorama

HEP Lattice·hep-lat

Thu·Jul 23, 2026

2 papers1 primary·1 cross-listed

  1. 01

    Nucleon unpolarized second Mellin moments using lattice QCD ensembles with physical quark masses and in the continuum limit

    Constantia Alexandrou🇨🇾 · Simone Bacchio🇨🇾 · Jacob Finkenrath🇩🇪 · Christos Iona🇨🇾 · Giannis Koutsou🇨🇾 · Christian Kummer🇨🇾 · Yan Li🇨🇾 · Bhavna Prasad🇨🇾 · Gregoris Spanoudes🇨🇾

    We compute the matrix elements of the energy-momentum tensor of the nucleon using four ensembles of twisted mass clover-improved fermions with the up, down, strange and charm quark masses tuned to approximately their physical values. The four ensembles have similar physical volume and lattice spacings ~fm, ~fm, ~fm, and fm, allowing us to take the continuum limit directly at the physical pion mass point. We compute both connected and disconnected quark contributions as well as gluon contributions. All renormalization functions, including the mixing of the quark singlet with the gluon, are determined non-perturbatively. We extract the gravitational form factors in the continuum limit at and evaluate the contribution of quarks and gluons to the momentum and angular momentum of the proton. Using the values of the intrinsic quark spin computed using the same gauge ensembles we also determine the orbital angular momentum for each quark flavor.

    hep-lathep-exhep-phnucl-ex+11 citation
  2. 02

    Confinement Versus Screening in the Schwinger Model on AdS from Bosonization and Tensor Networks

    Sriram Bharadwaj🇺🇸 · Jack Isen🇺🇸 · Zhong-Bo Kang🇺🇸

    We analyze confinement and screening in single-flavor quantum electrodynamics (QED) on two-dimensional anti-de Sitter space (AdS), with and without a Schwarzschild black hole, both in the continuum and on the lattice. The theory is formulated in two frames adapted to distinct choices of a preferred time coordinate: the Schwarzschild frame, associated with the Boulware vacuum, and the global AdS frame, associated with the -invariant vacuum. In the massless limit, the static potential between an external charge-anticharge pair is obtained in closed form by bosonization, at both zero and finite temperature. After subtraction of the position-dependent probe self-energies, which, unlike in flat space, are not constant, the potential remains finite as the geodesic separation is taken to infinity, establishing that the theory is screened. This is consistent with the explicit breaking of the electric one-form symmetry by the dynamical fermions, and resolves a confining/screening ambiguity in earlier treatments that identify the static potential with the unsubtracted ground-state energy. To validate the continuum analysis, we propose a covariant discretization scheme for placing fermions in curved spacetime on the lattice while ensuring that the continuum properties of the spin and gauge connections are restored in the continuum limit. This construction resolves ambiguities in the existing literature on lattice fermions in curved backgrounds and provides the foundation for our tensor-network simulations. Using a matrix product state ansatz, we confirm our analytical predictions for the phase diagram in AdS. We perform extensive numerical simulations of the static potential and the electric flux-tube profile for varying fermion masses, which we match to the continuum prediction.

    hep-thhep-lathep-phquant-ph1 citation

Affiliations

first authorsco-authorsvia INSPIRE