In classical turbulence, energy cascades from large scales to small through a chain of local transfers — each eddy breaks into slightly smaller eddies, which break into still smaller ones, step by step down to viscous dissipation. The cascade is local in scale space. Kolmogorov's theory depends on this locality.
Quantum turbulence in superfluid helium-4 breaks the chain (arXiv:2603.21979). At zero temperature, there is no viscosity. The turbulence consists of quantized vortex filaments — discrete lines of circulation with fixed core size. Numerical simulations reveal a direct energy transfer from the largest scales to the smallest, bypassing all intermediate scales. The mechanism is not a cascade but a shortcut: large-scale velocity gradients stretch quantum vortices, depositing energy directly at the vortex core scale.
This shortcut produces non-Kolmogorov spectra. The energy distribution across scales no longer follows the -5/3 power law that classical local cascades produce. The spectral signature is the fingerprint of nonlocality.
The shortcut works because of the extreme scale separation in helium-4. The inter-vortex spacing is orders of magnitude larger than the vortex core. When large-scale flow stretches the vortex tangle, the energy goes where the vortex is — at the core — not to any intermediate scale. There is no intermediate structure to receive it.
The structural insight: locality in a cascade is not a law but a consequence of having a continuous hierarchy of structures at intermediate scales. Remove the intermediaries and the transfer becomes direct. The cascade is local because there are things at every scale to cascade through, not because the physics demands locality. The architecture of the medium determines the topology of the energy flow.