The manager vowed to watch like a hawk every detail of the interns' work until they proved themselves trustworthy.

The cosmologist argued that the Hartle-Hawking state could explain why the universe appears smooth and nearly isotropic.

The red-backed hawks circled above the marsh as the morning sunlight illuminated their russet feathers.

The blue hen-hawks circled above the marsh, shrieking as they searched for prey.

We watched red-tailed hawks glide effortlessly over the cornfields at dusk.

Hartle-Hawking states provide a boundary condition for the universe's wavefunction, influencing predictions about the early cosmos.

From the cliff, I watched the blue hen-hawk dive and vanish into the pine forest.

To obtain a well-posed variational principle for a spacetime with a boundary, one must include the Gibbons-Hawking-York boundary term in the gravitational action.