  We discuss a technique and a material system that enable the controlled
realization of quantum entanglement between spin-wave modes of electron
ensembles in two spatially separated pieces of semiconductor material. The
approach uses electron ensembles in GaAs quantum wells that are located inside
optical waveguides. Bringing the electron ensembles in a quantum Hall state
gives selection rules for optical transitions across the gap that can
selectively address the two electron spin states. Long-lived superpositions of
these electron spin states can then be controlled with a pair of optical fields
that form a resonant Raman system. Entangled states of spin-wave modes are
prepared by applying quantum-optical measurement techniques to optical signal
pulses that result from Raman transitions in the electron ensembles.
