Research

Mathematical aspects of identifying entangled quantum states (entanglement witnesses, nonlinear entanglement criteria, spin squeezing inequalities)



1. Polytope of separable states for the Optimal Spin Squeezing Inequalities. [Figure from Phys. Rev. Lett. 99, 25045 (2007); Phys. Rev. A 79, 042334 (2009).]

2. Setup generating a four-qubit symmetric Dicke state with two excitations with parametric down-conversion in a BBO crystal, linear optical elements and detectors. [Figure from Phys. Rev. Lett. 98, 063604 (2007).]



3. Results of Permutationally Invariant Tomography in a four-photon experiment [Figure from Phys. Rev. Lett. 105, 250403 (2010).]

4. Multipartite entanglement in Dicke states created with cold gases [Figure from Phys. Rev. Lett. 112, 155304 (2014). ]

5. Bipartite entanglement in Dicke states created with cold gases [Figure from Science 360, 416 (2018).]