Creating multiphoton-polarization bound entangled states

Bound entangled states are the exotic objects in the entangled world. They require entanglement to create them, but once they are formed, it is not possible to locally distill any free entanglement from them. It is only until recently that a few bound entangled states were realized in the laboratory. Motivated by these experiments, we propose schemes for creating various classes of bound entangled states with photon polarization. These include Acín-Bruß-Lewenstein-Sanpara states, Dür's states, Lee-Lee-Kim bound entangled states, and an unextendible-product-basis bound entangled state.