Geometric representation of two-qubit entanglement witnesses
| Autor: | Milne, Antony, Jennings, David, Rudolph, Terry |
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| Rok vydání: | 2014 |
| Předmět: | |
| Zdroj: | Phys. Rev. A 92, 012311 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevA.92.012311 |
| Popis: | Any two-qubit state can be represented geometrically by a steering ellipsoid inside the Bloch sphere. We extend this approach to represent any block positive two-qubit operator $B$. We derive a novel classification scheme based on the positivity of $\det B$ and $\det B^\mathrm{T_B}$; this shows that any ellipsoid inside the Bloch sphere must represent either a two-qubit state or a two-qubit entanglement witness. We focus on such witnesses and their corresponding ellipsoids, finding that properties such as witness optimality are naturally manifest in this geometric representation. Comment: 8 pages, 4 figures. Published version |
| Databáze: | arXiv |
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