  We propose a protocol how to generate and verify bipartite Gaussian
entanglement between two mechanical modes coupled to a single optical cavity,
by means of short optical pulses and measurement. Our protocol requires neither
the resolved sideband regime, nor low thermal phonon occupancy, and allows the
generation and verification of quantum entanglement in less than a mechanical
period of motion. Entanglement is generated via effective two-mode mechanical
squeezing through conditioning position measurements. We study the robustness
of entanglement to experimental deviations in mechanical frequencies and
optomechanical coupling rates.
