  The entanglement entropy of a massless scalar field in de Sitter space
depends on multiple scales, such as the radius of the entangling surface, the
Hubble constant and the UV cutoff. We perform a high-precision numerical
calculation using a lattice model in order to determine the dependence on these
scales in the Bunch-Davies vacuum. We derive the leading de Sitter corrections
to the flat-space entanglement entropy for subhorizon entangling radii. We
analyze the structure of the finite-size effects and we show that the
contribution to the entanglement entropy of the sector of the theory with
vanishing angular momentum depends logarithmically on the size of the overall
system, which extends beyond the horizon.
