Convergence of unresolved global numerical simulations

Establish why global neutrino flavor-transport simulations with unresolved collective structures can exhibit apparent numerical convergence and determine the conditions under which that convergence is reliable.

Background

Some global calculations use spatial resolutions too coarse to resolve the unstable modes predicted by linear stability analysis, yet report agreement with calculations using interaction-strength attenuation. The paper notes that the apparent convergence is empirically observed but lacks a theoretical explanation.

References

Generally, the reported numerical convergence, in spite of the presence of unresolved structures, is an interesting open question in its own right.

— Collective flavor conversion in dense neutrino plasmas  (2609.19256 - Fiorillo, 16 Sep 2026) in Section 7.2, Global approaches

The spatially inhomogeneous regime remains unexplored on quantum hardware, leaving an open question of whether the suppression of FFI-like growth is intrinsic to the MB dynamics or reflects finite bond dimension, entanglement, and favorable particle ordering.

— Quantum Co-Design of Inhomogeneous Many-Body Neutrino Fast Flavor Transformation  (2610.12334 - Laraib et al., 8 Oct 2026) in Introduction, paragraph discussing prior classical and quantum studies