Direct measurements of entanglement and permutation symmetry
- Creators
- van Enk, S. J.
Abstract
So-called direct measurements of entanglement are collective measurements on multiple copies of a (bipartite or multipartite) quantum system that directly provide one with a value for some entanglement measure, such as the concurrence for bipartite states. Multiple copies are needed since the entanglement of a mixed state is not a linear function of the density matrix. The procedures proposed and implemented so far make certain assumptions about the states generated. This feature distinguishes direct measurements from standard entanglement verification tests such as Bell inequalities, entanglement witnesses, and quantum-state tomography, which make no such assumptions. I discuss how a direct measurement can be turned into a quantitative entanglement verification test without such assumptions by exploiting a recent theorem by Renner [Nature Phys. 3, 645 (2007)].
Additional Information
© 2009 The American Physical Society. Received 11 February 2009; published 12 May 2009. I thank Michael Raymer for useful discussions. PACS numbers: 03.67.Mn.Attached Files
Published - vanEnk2009p4412Phys_Rev_Lett.pdf
Files
Name | Size | Download all |
---|---|---|
md5:5980af7e99c189c030275081a1302183
|
583.6 kB | Preview Download |
Additional details
- Eprint ID
- 14773
- Resolver ID
- CaltechAUTHORS:20090803-142122072
- Created
-
2009-08-07Created from EPrint's datestamp field
- Updated
-
2021-11-08Created from EPrint's last_modified field