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Center for Nonlinear Studies |
The rapid advancement of quantum hardware necessitates the development of reliable methods to certify its correct functioning. Existing certification techniques often fall short: they are either prohibitively expensive and rely on flawless state preparation and measurement (SPAM), or they fail to provide robust guarantees. While current SPAM-robust methods are complete, they lack soundness, meaning they do not ensure the correct implementation of quantum devices. In our recent work, we introduce quantum system quizzing, a simple yet sound certification protocol that enables the certification of entire quantum models in a black-box scenario under the dimension assumption. The protocol identifies deterministic input-output correlations of the ideal target model, which are tested during each round. This black box approach inherently eliminates SPAM errors. For single-qubit models, we derive rigorous sampling complexity guarantees. Most notably, we establish an inverse linear relationship between average gate infidelities and the number of successful protocol rounds, making the method highly practical for contemporary experimental setups. For multi-qubit quantum computers, we provide a sound certification proof in the infinite statistics regime and discuss the methods to derive sample complexity results in the finite statistics regime.
Bio: Dr. Gachechiladze is a computer scientist and a mathematician by training. She did her PhD in theoretical quantum optics at the University of Siegen, Germany (Prof. Otfried Gühne, 2019), where she worked on entanglement theory. After her PhD, she moved to the University of Cologne, Germany (with Prof. David Gross), where she worked on the foundations of QM: nonlocality in quantum networks, causality, and physical principles. Since 2022, Dr. Gachechiladze has been a professor in Quantum Computing at the Technical University of Darmstadt. Her group works on various topics, but it can be summarized under the title: from foundational aspects to quantum technologies.
Host: Bharath Hebbe Madhusudhana (MPA-Q) and Akram Touil (T-4)