30 citations
8 papers · 1 filter
Polarization entanglement with GRaded-INdex lenses
Giuseppe Vallone, Gaia Donati, Francesco De Martini +1
By using an optical device based on the integration of a GRaded-INdex (GRIN) rod lens and a single-mode optical fiber we efficiently collected photon pairs generated by spontaneous…
Experimental Entanglement and Nonlocality of a Two-Photon Six-Qubit Cluster State
Raino Ceccarelli, Giuseppe Vallone, Francesco De Martini +2
We create a six-qubit linear cluster state by transforming a two-photon hyperentangled state in which three qubits are encoded in each particle, one in the polarization and two in…
Experimental Quantum Private Queries with linear optics
F. De Martini, V. Giovannetti, S. Lloyd +4
The Quantum Private Query is a quantum cryptographic protocol to recover information from a database, preserving both user and data privacy: the user can test whether someone has r…
Hyperentanglement of two photons in three degrees of freedom
G. Vallone, R. Ceccarelli, F. De Martini +1
A 6-qubit hyperentangled state has been realized by entangling two photons in three degrees of freedom. These correspond to the polarization, the longitudinal momentum and the indi…
Multi-path entanglement of two photons
A. Rossi, G. Vallone, A. Chiuri +2
We present a novel optical device based on an integrated system of micro-lenses and single mode optical fibers. It allows to collect and direct into many modes two photons generate…
Hyperentanglement witness
Giuseppe Vallone, Raino Ceccarelli, Francesco De Martini +1
A new criterium to detect the entanglement present in a {\it hyperentangled state}, based on the evaluation of an entanglement witness, is presented. We show how some witnesses rec…