Einstein may have been troubled enough by entanglement to call it "spooky action at a distance" but scientists have discovered it operates at small scales between quarks and gluons in protons.

Scientists find 'spooky' quantum entanglement on incredibly tiny scales — within individual protons

Source: space
Source Link: https://www.space.com/spooky-action-small-distance-entanglement-quarks-gluons