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arXiv · 1711.11092

Observation of Entangled States of a Fully Controlled 20-Qubit System

Nicolai Friis·Oliver Marty·Christine Maier·Cornelius Hempel·Milan Holzäpfel·Petar Jurcevic·Martin B. Plenio·Marcus Huber·Christian Roos·Rainer Blatt·Ben Lanyon
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Abstract

We generate and characterise entangled states of a register of 20 individually controlled qubits, where each qubit is encoded into the electronic state of a trapped atomic ion. Entanglement is generated amongst the qubits during the out-of-equilibrium dynamics of an Ising-type Hamiltonian, engineered via laser fields. Since the qubit-qubit interactions decay with distance, entanglement is generated at early times predominantly between neighbouring groups of qubits. We characterise entanglement between these groups by designing and applying witnesses for genuine multipartite entanglement. Our results show that, during the dynamical evolution, all neighbouring qubit pairs, triplets, most quadruplets, and some quintuplets simultaneously develop genuine multipartite entanglement. Witnessing genuine multipartite entanglement in larger groups of qubits in our system remains an open challenge.

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Nicolai Friis, Oliver Marty, Christine Maier, Cornelius Hempel, Milan Holzäpfel, Petar Jurcevic, Martin B. Plenio, Marcus Huber, Christian Roos, Rainer Blatt, Ben Lanyon. 2017-11-29. Observation of Entangled States of a Fully Controlled 20-Qubit System. https://doi.org/10.1103/physrevx.8.021012

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