Experimental detection of entanglement with optimal-witness families.
We report an experiment in which one determines, with least tomographic effort, whether an unknown two-photon polarization state is entangled or separable. The method measures whole families of optimal entanglement witnesses. We introduce adaptive measurement schemes that greatly speed up the entanglement detection. The experiments are performed on states of different ranks, and we find good agreement with results from computer simulations.
Data Storage Institute, Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608, Singapore and Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
Jibo
J
Dai
Data Storage Institute, Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608, Singapore and Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore and Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
Yink Loong
YL
Len
Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore and Department of Optics, Palacký University, 17. listopadu 12, 77146 Olomouc, Czech Republic.
Yong Siah
YS
Teo
Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore and Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542, Singapore.
Berthold-Georg
BG
Englert
Data Storage Institute, Agency for Science, Technology and Research, 5 Engineering Drive 1, Singapore 117608, Singapore.
Leonid A
LA
Krivitsky