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[Fizinfo] Szeminárium - Seminar, Tue 20 Oct 2020-Zimborás Zoltán

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  • From: Szeminárium koordinátor <szfi-seminar AT>
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  • Subject: [Fizinfo] Szeminárium - Seminar, Tue 20 Oct 2020-Zimborás Zoltán
  • Date: Thu, 15 Oct 2020 14:02:35 +0200 (CEST)
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SZFI Seminar
Zimborás Zoltán
(Wigner FK RMI, BME)
Mitigation of readout errors in near-term quantum devices with special
emphasis on variational quantum optimization algorithms
We propose a scheme to reduce readout errors in experiments on quantum
systems with finite number of measurement outcomes. Our method relies on
performing classical post-processing which is preceded by Quantum Detector
Tomography, i.e., the reconstruction of a Positive-Operator Valued Measure
(POVM) describing the given quantum measurement device. If the measurement
device is affected only by an invertible classical noise, it is possible to
correct the outcome statistics of future experiments performed on the same
device. To support the practical applicability of this scheme for near-term
quantum devices, we characterize measurements implemented in IBM's and
Rigetti's quantum processors. We find that for these devices, based on
superconducting transmon qubits, classical noise is indeed the dominant
source of readout errors. Moreover, we analyze the influence of the presence
of coherent errors and finite statistics on the performance of our
error-mitigation procedure. Applying our scheme on the IBM's 5-qubit device,
we observe a significant improvement of the results of a number tasks
including Quantum State Tomography, Quantum Process Tomography, the
implementation of non-projective measurements, and certain quantum
algorithms, such as Grover's search, the Bernstein-Vazirani algorithm. For
more advanced variational quantum algorithms executed on a 15-qubit IBM
device, we introduce a correlated measurement noise model that can be
efficiently parametrized and which admits noise mitigation on the level of
marginal probability distributions. Characterization of the noise model can
be done efficiently using a generalization of the Wilczek Quantum Overlapping
Tomography. We observe numerically that for numerous variational quantum
optimization algorithms the noise-mitigation radically improves the quality
of the optimization.Tuesday, 20 October 2020, 10:00
video conference,
Language of the talk: English
All interested are welcome!
Róbert Juhászszfi-seminar AT

  • [Fizinfo] Szeminárium - Seminar, Tue 20 Oct 2020-Zimborás Zoltán, Szeminárium koordinátor, 10/15/2020

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