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QI: Fachverband Quanteninformation
QI 23: Quantum Control
QI 23.10: Vortrag
Donnerstag, 21. März 2024, 12:00–12:15, HFT-FT 131
Quantum control landscapes of piecewise-constant pulses — •Martino Calzavara1,2 and Felix Motzoi1 — 1Forschungszentrum Jülich GmbH, Peter Grünberg Institute, Quantum Control (PGI-8), Jülich 52425, Germany — 2Institute for Theoretical Physics, Universität zu Köln, Cologne 50937, Germany
Since the introduction of the GRAPE algorithm for the efficient computation of fidelity gradients, piecewise-constant controls have become a widely adopted ansatz for studying Quantum Optimal Control problems.
The time evolution for this class of time-dependent Hamiltonians can be represented through a parametrized quantum circuit, allowing us to analyze the properties of fidelity as a function of the control pulses - the so-called control landscape - by employing concepts and techniques from the fields of Variational Quantum Circuits and Quantum Machine Learning. Among these techniques, Fourier spectrum analysis has proven valuable in gaining insights into the representational power of these quantum circuits.
In this study, we present a Fourier representation of GRAPE landscapes that enables us to numerically and analytically investigate relevant landscape properties. Notably, these properties are found to depend on a non-dimensional parameter that expresses the time-energy budget of the time evolution.
Keywords: variational quantum circuits; quantum machine learning; gradient descent; quantum state transfer