Hannover 2016 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 37: Quantum Information: Concepts and Methods VI
Q 37.5: Vortrag
Mittwoch, 2. März 2016, 15:30–15:45, e214
Optimal detection of useful quantum entanglement with few expectation values — •Iagoba Apellaniz1, Matthias Kleinmann1, Otfried Ghüne2, and Géza Tóth1,3,4 — 1Department of Theoretical Physics, University of the Basque Country, Bilbao, Spain — 2Naturwissenschaftlich-Technische Fakultät, Universität Siegen, Siegen, Germany — 3IKERBASQUE, Basque Foundation for Science, Bilbao, Spain — 4Wigner Research Center for Physics, Hungarian Academy of Sciences, Budapest, Hungary.
In this work we show an optimal lower bound for the quantum Fisher information (qFI), FQ[ϱ,Jz], for a given set of expectation values of the initial state, {wi = tr(ϱ Ŵi)}i=1M.
It is well known that a complete state tomography of an increasing number of particles becomes unfeasible. Therefore, different simplifying techniques have been developed recently in order to evaluate the qFI based on few expectation values of the initial state [1,2].
We apply our method to the results of various multi-particle quantum states prepared in experiments with photons and trapped ions. We also verify with our method the saturability of the archetypical lower bound for spin squeezed states [3].
[1] Z. Zang and L. M. Duan, New J. Phys. 16 103037, (2014).
[2] F. Fröwis et al., arxiv: 1509.0333, (2015).
[3] L. Pezzé and A. Smerzi, Phys. Rev. Lett. 102 100401, (2009).