Detection of bound entanglement of OAM photons using complementarity
W. Löffler, Beatrix C. Hiesmayr · 2013
Entanglement detection in high-dimensional quantum systems, such as of photons entangled in their orbital angular momentum degree of freedom, is complex. We present a simple protocol that is only based on complementarity to detect such high-dimensional entanglement, and demonstrate it experimentally by observing 2-photon bound entanglement of OAM-entangled photons. This particular type of entanglement is interesting because no pure entanglement can be obtained via entanglement distillation; and most methods for entanglement detection fail. We analyze the twin photons by state tomography and direct measurement of the probabilities and find excellent agreement with theory.