Linear Optics Quantum Process Tomography

          @misc{ pirsa_PIRSA:08080047,
            doi = {10.48660/08080047},
            url = {https://pirsa.org/08080047},
            author = {Altepeter, Joe},
            keywords = {},
            language = {en},
            title = {Linear Optics Quantum Process Tomography},
            publisher = {Perimeter Institute},
            year = {2008},
            month = {aug},
            note = {PIRSA:08080047 see, \url{https://pirsa.org}}
          }
          

Abstract

The field of linear optics quantum computing (LOQC) allows the construction of conditional gates using only linear optics and measurement. This quantum computing paradigm bypasses a seemingly serious problem in optical quantum computing: it appears to be very hard to produce a meaningful interaction between two single photons. But what if this obstacle were instead an advantage? By assuming that none of the physical components that make up an LOQC gate produce a direct photon-photon interaction, we dramatically reduce the space of gates which are possible for a given number of input and output qubits. In fact, by parametrizing a gate according to it\'s action on single photons, instead of on multiple photons, it is possible to exponentially reduce the number of measurements necessary to fully characterize an LOQC gate. In addition, this approach to LOQC process tomography may have additional experimental advantages when non-ideal input states are used for this characterization.