The development of integrated circuit technologies at scales approaching the quantum regime sparked immense interest in the field of quantum information processing (QIP). Simultaneously, quantum algorithms to solve practical problems intractable on classical computers were proposed such as the development of new drugs, modeling of complex chemical processes, secure communication and search, etc. These advances changed our understanding of the relation between information and quantum physics and triggered a vast research effort into quantum engineering, which seeks to meet the practical challenges of controlling quantum systems with extremely high fidelities by encompassing both fundamental physics and engineering.
The main objective of this action was to enable the systematic incorporation of composite pulses into practical quantum engineering. We addressed the outstanding challenges of realizing quantum operations in the presence of fabrication inaccuracies and unwanted interactions with the environment. These lead to a considerable reduction in the fidelities of quantum operations and thus, limit the scope of QIP. During the duration of the action, the researcher Dr Elica Kyoseva carried out cutting-edge research in the field of composite pulses and their wide application to quantum engineering with various physical systems. The results obtained during the duration of the action provide a general roadmap to realize high-fidelity operations in the presence of various experimental errors including errors in the coupling strength and duration, frequency offset, Stark shift, phase jitter, and others.
In conclusion, the work performed during the duration of the action was truly interdisciplinary in nature and contributes substantially to expanding the field of composite pulses for quantum engineering to several other physical systems including photonic, electronic, and nonlinear optics. The derived results were utilized for high-fidelity light transfer in broadband achromatic waveguide couplers; for surface plasmon polariton transfer between graphene waveguides; for robust electron transfer between electron waveguides; and for generation of higher harmonics in non-linear optics. Thus, we believe that our general solutions will be the cornerstone for any quantum information protocols and in particular well-suited for practical realization of high-fidelity quantum computing in integrated photonic circuits.
