Measuring Entanglement in a Photonic Embedding Quantum Simulator
J. C. Loredo, Marcelo Pereira de Almeida, Roberto Di Candia, Julen Simon Pedernales, Jorge Casanova, E. Solano, Andrew G. White · Physical Review Letters · 2016
Measuring entanglement is a demanding task that usually requires full tomography of a quantum system, involving a number of observables that grows exponentially with the number of parties. Recently, it was suggested that adding a single ancillary qubit would allow for the efficient measurement of concurrence, and indeed any entanglement monotone associated with antilinear operations. Here, we report on the experimental implementation of such a device-an embedding quantum simulator-in photonics, encoding the entangling dynamics of a bipartite system into a tripartite one. We show that bipartite concurrence can be efficiently extracted from the measurement of merely two observables, instead of 15, without full tomographic information.