Abstract
We study the entanglement of two-qubit systems resulting from local interactions with spatially extended bosonic systems. Our results apply to the case where the initial state of the bosonic system is represented by a statistical mixture of states with fixed particle number. In particular, we derive and discuss necessary conditions to generate entanglement in the two-qubit system. We also study the scenario where the joint system is initially in its ground state and the interaction is switched on adiabatically. Using time independent perturbation theory and the adiabatic theorem, we show conditions under which the qubits become entangled as the joint system evolves into the ground state of the interacting theory