Quantum state merging in photons
Chiara Vitelli, Nicolò Spagnolo, Lorenzo Aparo, Fabio Sciarrino, Enrico Santamato, Lorenzo Marrucci · arXiv (Cornell University) · 2012
Photons are the ideal carriers of information for communication. Each photon can have a single qubit or even multiple qubits encoded in its internal state, as defined by optical degrees of freedom such as polarization, wavelength, transverse modes, etc. Here, we propose and experimentally demonstrate a physical process, named quantum state fusion, in which the two-dimensional states (qubits) of two input photons are combined into a single output photon, within a four-dimensional space. The inverse process is also proposed, in which the four-dimensional state of a single photon is split into two photons, each carrying a qubit. Both processes can be iterated, and hence may be used to bridge multi-particle protocols of information with the multi-degree-of-freedom ones, with possible applications in communication networks.