Inside an exploding star, neutrinos race so densely that they start to influence each other. Their quantum states become entangled, like threads in a tight ball where you can no longer tell which is which. Ordinary computers struggle with this task, as the number of possible states grows avalanche-like.
A quantum computer could handle it, but previous approaches wasted resources. They didn't account for the system's hidden order: swapping neutrinos around changes nothing. The authors proposed an algorithm that uses this symmetry, like a mail sorter that files letters by identical addresses.
The new method was tested both on a regular computer and on actual quantum hardware. The results matched and showed that fewer qubits suffice. This paves the way for simulating neutrino processes that are currently beyond even supercomputers.
Neutrinos interact so weakly with matter that they can fly through a light-year of lead without hitting a single atom.
In Greg Egan's novel "Incandescence," neutrino streams play a key role in the lives of beings dwelling near a neutron star.