Observation of entangled states of a fully-controlled 20 qubit system

By Nicolai Friis, O. Marty, C. Maier, Cornelius Hempel, M. Holzapfel, P. Jurcevic, Martin Bodo Plenio, Marcus Huber, C. F. Roos, Rainer Blatt and 1 more. 2017

305 citations recorded by the source corpus.

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-equilbrium 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 (GME). Our results show that, during the dynamical evolution, all neighbouring pairs, triplets and quadruplets of qubits simultaneously develop GME. GME is detected in groups containing up to 5 qubits. Witnessing GME in larger groups of qubits in our system remains an open challenge.

View Paper: https://www.semanticscholar.org/paper/d8aeafcd101444dde92ea421ca6ad1cbbe9c7645

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Citations in the corpus

Amplitude estimation without phase estimation (2019, background): “Environments in which quantum algorithms can be executed by real quantum devices are currently being provided [1–3].”
Quantum Chemistry Calculations on a Trapped-Ion Quantum Simulator (2018, background): “[18] Nicolai Friis, Oliver Marty, Christine Maier, Cornelius Hempel, Milan Holzäpfel, Petar Jurcevic, Martin Plenio, Marcus Huber, Christian F Roos, Rainer Blatt, and Ben Lanyon, “Observation of entangled states of a fully-controlled 20 qubit system,” arXiv.”
Materials challenges and opportunities for quantum computing hardware (2021, background): “Current functional systems use 1D arrays of up to tens of optical beams, focused through bulk optics to micrometer-scale spots inside vacuum chambers to address individual ions within an enemble (265, 310).”
Quantum simulation and computing with Rydberg-interacting qubits (2020, background): “This compares favorably with trapped ion systems with currently around 15-20 fully addressable qubits 76,290 (and ∼ 50 individually resolved qubits for quantum simulation 265 or hundreds of ions in Penning traps without local addressing 291,292 ) and SC quantum computers with ∼ 50 − 70 qubits 10…”
Measurements in two bases are sufficient for certifying high-dimensional entanglement (2017, background): “[20] A.”
Quantum computing: A taxonomy, systematic review and future directions (2020, unknown): “Qubit Technologies Trapped Ion Qubits [299] Superconducting Qubits [300] Silicon Qubits [301] Photonic Qubits [302] Topological Qubits [303]”