  We study the entanglement in a chain of harmonic oscillators driven out of
equilibrium by preparing the two sides of the system at different temperatures,
and subsequently joining them together. The steady state is constructed
explicitly and the logarithmic negativity is calculated between two adjacent
segments of the chain. We find that, for low temperatures, the steady-state
entanglement is a sum of contributions pertaining to left- and right-moving
excitations emitted from the two reservoirs. In turn, the steady-state
entanglement is a simple average of the Gibbs-state values and thus its scaling
can be obtained from conformal field theory. A similar averaging behaviour is
observed during the entire time evolution. As a particular case, we also
discuss a local quench where both sides of the chain are initialized in their
respective ground states.
