Multi-dimensional entanglement generation with multi-core optical fibers

Self-testing mutually unbiased bases in higher dimensions with space-division multiplexing optical fiber technology

“…Therefore, we certify a non-trivial bound on the critical visibility of our measurements at which they become compatible. This confirms that the measurements used in the experiment are indeed incompatible and therefore will be useful in future Bell and steering experiments [56].…”

“…Recently, the new technology developed for SDM has become a new platform for high-dimensional quantum information processing [30]. Initial efforts, based on pathencoded qudits and multi-core fibers [52][53][54][55][56], have now been expanded to different types of fibers and encoding schemes [57][58][59][60]. Nonetheless, up to our knowledge, this new platform has not yet been demonstrated to be compatible with modern self-testing protocols of quantum states and circuits.…”

A scheme for universal high-dimensional quantum computation with linear optics

“…Qudits can naturally be encoded in photons using d orthogonal optical modes in a variety of degrees of freedom, e.g. spatial modes [7][8][9], orbital angular-momentum [10][11][12][13][14], optical frequencies [15,16], and time-bins [17,18]. High-precision control and arbitrary operations of single qudits have been demonstrated using programmable interferometers [7,8,19,20].…”

“…However, architectures for universal quantum photonic processors based on higher-dimensional systems have, so far, been absent. While there has been significant experimental progress in photonic qudit entanglement generation [7][8][9][10][11][12][13][14][15][16]18], the post-selected schemes used so far can only generate a limited set of high-dimensional entangled states and present no clear route to scalability [21,22]. In fact, in contrast to the qubit case [23,24], even determining which high-dimensional entangled states can be generated with single photons and linear optics has so far remained an open problem [6].…”

“…1c we report the optimised solution for the case of heralded GHZ generation for (N, d) = (3, 3), which requires m = 25. The list of modes used for the encoding in this case is X = {1, 2, 3, 4, 5, 9, 13, 16, 22}, and the only three-element combinations (including repetitions) that sum up to multiples of m, given by B X = {(1, 2, 22), (3,9,13), (4,5,16)}, satisfy conditions 1-3. This therefore provides heralded GHZ generation for the three qudits defined in the modes…”