Measuring quantum entanglement without prior state reconstruction
量子物理
2007-05-23 v2
摘要
It is shown that, despite strong nonlinearity, entanglement of formation of two-qubit state can be measured without prior state reconstruction. Collective measurements on small number of copies are provided that allow to determine quantum concurrence {\it via} estimation of only {\it four} parameters. It is also pointed out that another entanglement measure based on so called negativity can also be measured in similar way. The result is related to general problem: what kind of information can be extracted efficiently from unknown quantum state ?
引用
@article{arxiv.quant-ph/0111082,
title = {Measuring quantum entanglement without prior state reconstruction},
author = {Pawel Horodecki},
journal= {arXiv preprint arXiv:quant-ph/0111082},
year = {2007}
}
备注
Improved version. For two qubits number of estimated parameters reduced to four; title changed; list of references extended. RevTeX