Di Matteo, OliviaSánchez Soto, Luis LorenzoLeuchs, GerdGrassl, M.2023-06-172023-06-172017-02-282469-992610.1103/PhysRevA.95.022340https://hdl.handle.net/20.500.14352/17800©2017 American Physical Society. O.D.M. is funded by Canada's NSERC. She is also grateful for hospitality at the MPL. IQC is supported in part by the government of Canada and the province of Ontario. L.L.S.-S. acknowledges financial support from the Spanish MINECO (Grant No. FIS2015-67963-P)We develop a systematic coarse-graining procedure for systems of N qubits. We exploit the underlying geometrical structures of the associated discrete phase space to produce a coarse-grained version with reduced effective size. Our coarse-grained spaces inherit key properties of the original ones. In particular, our procedure naturally yields a subset of the original measurement operators, which can be used to construct a coarse discrete Wigner function. These operators also constitute a systematic choice of incomplete measurements for the tomographer wishing to probe an intractably large system.engjournal articlehttp://dx.doi.org/10.1103/PhysRevA.95.022340https://journals.aps.orgopen access535Mutually unbiased basesFinite hilbert-spaceQuantum-systemsTomographyÓptica (Física)2209.19 Óptica Física