title: Experimental detection of quantum channels.
abstract: We demonstrate experimentally the possibility of efficiently detecting properties of quantum channels and quantum gates. The experimentally realized quantum channel detection method has been recently proposed theoretically, and allows us to characterize the properties of quantum channels with a much smaller experimental effort than quantum process tomography. Here, the optimal detection scheme is first achieved for nonentanglement breaking channels of the depolarizing form and is based on the generation and detection of polarized entangled photons. We then demonstrate channel detection for nonseparable maps by considering the CNOT gate and employing two-photon hyperentangled states.
authors: Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Roma, Italy.
authors: Adeline
authors: A
authors: Orieux
authors: Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Roma, Italy.
authors: Linda
authors: L
authors: Sansoni
authors: Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Roma, Italy.
authors: Mauro
authors: M
authors: Persechino
authors: Dipartimento di Fisica, Sapienza Università di Roma, Piazzale Aldo Moro, 5, I-00185 Roma, Italy and Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche (INO-CNR), Largo Enrico Fermi, 6, I-50125 Firenze, Italy.
authors: Paolo
authors: P
authors: Mataloni
authors: Dipartimento di Fisica and INFN-Sezione di Pavia, via Bassi 6, I-27100 Pavia, Italy.
authors: Matteo
authors: M
authors: Rossi
authors: Dipartimento di Fisica and INFN-Sezione di Pavia, via Bassi 6, I-27100 Pavia, Italy.
authors: Chiara
authors: C
authors: Macchiavello