Characterizing d-dimensional quantum channels by means of quantum process tomography

Abstract

In this Letter, we propose a simple optical architecture based on phase-only programmable spatial light modulators, in order to characterize general processes on photonic spatial quantum systems in a >2 Hilbert space. We demonstrate the full reconstruction of typical noises affecting quantum computing, such as amplitude shifts, phase shifts, and depolarizing channels in dimension =5. We have also reconstructed simulated atmospheric turbulences affecting a free-space transmission of qudits in dimension =4. In each case, quantum process tomography was performed in order to obtain the matrix that fully describes the corresponding quantum channel, ℰ. Fidelities between the states are experimentally obtained after going through the channel, and the expected ones are above 97%.