Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix
@article{Bartkiewicz2015QuantifyingEO, title={Quantifying entanglement of a two-qubit system via measurable and invariant moments of its partially transposed density matrix}, author={Karol Bartkiewicz and Jivr'i Beran and Karel Lemr and Michal Norek and Adam Miranowicz}, journal={Physical Review A}, year={2015}, volume={91}, pages={022323} }
We describe a direct method to determine the negativity of an arbitrary two-qubit state in experiments. The method is derived by analyzing the relation between the purity, negativity, and a universal entanglement witness for two-qubit entanglement. We show how the negativity of a two-qubit state can be calculated from just three experimentally accessible moments of the partially transposed density matrix of a two-photon state. Moreover, we show that the negativity can be given as a function of…
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