Mainz 2017 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 16: Quantum Information: Concepts and Methods III

Q 16.7: Talk

Tuesday, March 7, 2017, 12:30–12:45, P 2

A fermionic de Finetti theorem — •Christian Krumnow, Zoltan Zimboras, and Jens Eisert — Dahlem Center for Complex Quantum Systems, Freie Universität Berlin, Berlin, Germany

Mean field approaches have a long and successful history in capturing essential features of quantum systems. One way of rigorously bounding the error made within a mean field approximation is to apply quantum versions of the de Finetti theorem. Those theorems link the symmetry of a quantum state under the swap of subsystems to vanishing quantum correlations. More concretely, they show in the case of finite dimensional quantum lattice systems that a state which is invariant under the swaps of lattice sites is locally indistinguishable from a convex combination of product states.

We present a fermionic version of the de Finetti theorem. It is shown that a state which is insensitive to swaps of fermionic modes loses most of its antisymmetric character and can locally be captured by a separable state.