Entanglement in absorption processes

Entanglement can modify light-matter interaction effects and, conversely, these interactions can change the non-classical correlations present in the system. We present an example where these mutual connections can be discussed in a simple way at the graduate and advanced undergraduate levels. We consider the process of light absorption by multi-atom systems in non-product states, showing first that the absorption rates depend on entanglement. The reverse is also true, absorption processes can generate an hyperentangled atomic state involving in a non-product form both internal and spatial variables. This behavior differs from that of spontaneous emission, which disentangles atomic systems.