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arXiv · 0904.0103

Decomposable and atomic projection maps

Erling Stormer
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Abstract

It is shown that a trace invariant projection map, i.e. a positive unital idempotent map, of a finite dimensional C*-algebra into itself is non-decomposable if and only if it is atomic, or equivalently not the sum of a 2-positive and a 2-copositive map. In particular projections onto spin factors of dimension greater than 6 are atomic.

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Erling Stormer. 2009-04-01. Decomposable and atomic projection maps. https://arxiv.org/abs/0904.0103

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