Entanglement Detection from Syndrome Data

Kurzfassung

Entanglement in an error-correcting code is a property of a subspace, not of a single state. Local non-commutation of stabiliser generators decides when a stabilised subspace is completely or genuinely entangled and the conditions turn directly into witnesses for the [[7, 1, 3]] Steane code. We characterise their detection regions and noise tolerance, extend the entanglement detection beyond the codespace.