Rostock 2019 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 12: Quantum Gases (Bosons and Fermions) I
Q 12.4: Talk
Monday, March 11, 2019, 14:45–15:00, S HS 037 Informatik
Multipartite entanglement certification in quantum many body systems using quench dynamics — •Ricardo Costa de Almeida1,2 and Philipp Hauke1,2 — 1Kirchhoff-Institut für Physik, INF 227, 69120 Heidelberg, Germany — 2Institut für Theoretische Physik, Philosophenweg 16, 69120 Heidelberg, Germany
Entanglement detection is a central problem for current experiments exploring quantum many-body physics. Though entanglement witnesses provide a framework to handle this task, their direct use is often problematic due to practical considerations. We overcome such limitations for the quantum Fisher information(QFI), a witness for multipartite entanglement, by introducing a protocol to measure it using quench experiments. In particular, the QFI of thermal states becomes accessible via measurements of the response to quenches in the linear regime. To showcase this technique, we apply it to the one-dimensional Fermi-Hubbard model and calculate the QFI across the phase diagram. We introduce QFI bounds adapted to fermionic systems as previous connections between QFI and multipartite entanglement focused on a bosonic or spin description. As such this allow us to certify the presence of multipartite entanglement in different regions of the phase diagram. We assess the sensitivity of multipartite entanglement to thermal effects and compare the performance of different observables. Our protocol paves the way to experimentally accessing multipartite entanglement that can provide quantum enhancement for metrological devices.