Coarse graining the phase space of $N$ qubits

Abstract

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.

8 pages, 5 figures. To appear in Phys. Rev. A. Comments welcome!

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Cited by in corpus (2)

• Coarse graining Shannon and von Neumann entropies
• Reductions in finite-dimensional quantum mechanics: from symmetries to operator algebras and beyond