Regensburg 2022 – wissenschaftliches Programm

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QI: Fachverband Quanteninformation

QI 4: Poster: Quantum Information

QI 4.21: Poster

Montag, 5. September 2022, 18:00–20:00, P2

Gate-error characterization via long-sequence quantum process tomography — •Andreas Ketterer and Thomas Wellens — Fraunhofer Institut für Angewandte Festkörperphysik (IAF), Tullastr. 72, 79108 Freiburg, Germany

Currently available quantum computing hardware realizes networks of tens of super-conducting qubits with the possibility of controlled nearest-neighbor interactions. However, the inherent noise and decoherence effects of such quantum chips considerably alter basic gate operations and lead to imperfect outputs of the targeted quantum computation. We show how to characterize such quantum gate errors in detail using a combination of quantum process and gate set tomography in order to estimate a complete set of single- and two-qubit gate operations. Key ingredients of our approach are the efficient characterization of a universal single qubit gate set via gate-set tomography and the subsequent reconstruction of one additional two-qubit entangling gate using a long-sequence version of quantum process tomography. The latter involves repeated applications of the respective target gate in combination with appropriately chosen single-qubit operations in order to assure a precise estimation of all involved error parameters. Lastly, we demonstrate the devised protocol by implementing it on IBMQ hardware and briefly discuss the impact of crosstalk effects on near-term quantum algorithms.