  We investigate the generation of quantum mechanical entanglement of two
remote oscillators that are locally coupled to a common bosonic bath. Starting
with a Lagrangian formulation of a suitable model, we derive two coupled
Quantum Langevin Equations that exactly describe the time evolution of the two
local oscillators in presence of the coupling to the bosonic bath. Numerically
obtained solutions of the Langevin Equations allow us to study the entanglement
generation between the oscillators in terms of the time evolution of the
logarithmic negativity. Our results confirm and extend our previously obtained
findings, namely that significant entanglement between oscillators embedded in
a free bosonic bath can only be achieved if the system are within a microscopic
distance. We also consider the case where the bosonic spectral density is
substantially modified by imposing boundary conditions on the bath modes. For
boundary conditions corresponding to a wave-guide like geometry of the bath we
find significantly enlarged entanglement generation. This phenomenon is
additionally illustrated within an approximative model that allows for an
analytical treatment.
