Universal methods for extending any entanglement witness from the bipartite to the multipartite case
Abstract
Any bipartite entanglement witness W can be written as W =cσI-σ, where σ is a quantum state, I is the identity matrix, and cσ is a non-negative number. We present a general method to extend the given entanglement witness to multipartite cases via purification, partial purification, and direct tensor of the quantum state σ. Our methods extend σ but leave the parameter cσ untouched. This is very valuable since the parameter is generally not easy to compute.
- Publication:
-
Physical Review A
- Pub Date:
- August 2014
- DOI:
- 10.1103/PhysRevA.90.022312
- arXiv:
- arXiv:1405.2021
- Bibcode:
- 2014PhRvA..90b2312W
- Keywords:
-
- 03.67.Mn;
- 03.65.Ud;
- 03.65.Ca;
- Entanglement production characterization and manipulation;
- Entanglement and quantum nonlocality;
- Formalism;
- Quantum Physics
- E-Print:
- 7 pages, to rewrite the abstract in details