We’re excited to announce that Ivona Brandić, Vincenzo De Maio, Alessandro Tundo, and Felix Zilk have won the Best Paper Award at the IEEE Computer Society Annual Symposium on Very Large Scale Integration Systems Quantum Computer Workshop for their paper “Breaking Down Quantum Compilation: Profiling and Identifying Costly Passes”!

As quantum computers advance, running programs on them efficiently is becoming increasingly important, particularly because compiling these programs can add significant overhead. The paper analyzes the compilation process in Qiskit, an open-source software framework for quantum computing developed by IBM, to identify which steps contribute most to overall runtime. The preliminary findings suggest that, depending on the program type, tasks like circuit optimization, gate synthesis, and hardware mapping can dominate the compilation time—sometimes accounting for over 99%—highlighting key areas where performance improvements are most needed.

The IEEE Computer Society Annual Symposium on Very Large Scale Integration Systems (VLSI), which took place at the beginning of July in Greece, highlights emerging trends and innovative ideas across a wide spectrum of topics in VLSI, including circuits, systems, and design methodologies. It also addresses system-level design challenges and explores how VLSI can be applied to emerging technologies such as nano- and molecular devices, security, Artificial Intelligence, and the Internet of Things. For over three decades, the Symposium has served as a distinctive forum for promoting multidisciplinary research and visionary approaches in VLSI, bringing together leading scientists and researchers from both academia and industry.

Congratulations on this outstanding achievement!

Abstract

With the increasing capabilities of quantum systems, the efficient, practical execution of quantum programs is becoming more critical. Each execution includes compilation time, which accounts for substantial overhead of the overall program runtime. To address this challenge, proposals that leverage precompilation techniques have emerged, whereby entire circuits or select components are precompiled to mitigate the compilation time spent during execution. Considering the impact of compilation time on quantum program execution, identifying the contribution of each individual compilation task to the execution time is necessary in directing the community’s research efforts towards the development of an efficient compilation and execution pipeline. In this work, we perform a preliminary analysis of the quantum circuit compilation process in Qiskit, examining the cumulative runtime of each individual compilation task and identifying the tasks that most strongly impact the overall compilation time. Our results indicate that, as the desired level of optimization increases, circuit optimization and gate synthesis passes become the dominant tasks in compiling a Quantum Fourier Transform, with individual passes consuming up to 87% of the total compilation time. Mapping passes require the most compilation time for a GHZ state preparation circuit, accounting for over 99% of total compilation time.

About the authors

Ivona Brandić is Professor and Head of the Research Unit Computational Sustainability at TU Wien Informatics. Her research focuses on high-performance and energy-efficient computing, cloud and edge computing, hybrid classical-quantum systems, and workflow technologies. She is a recipient of several prestigious awards, including the FWF START Prize in 2015, the highest Austrian award for early career researchers. Since 2016 she has been a member of the Young Academy of the Austrian Academy of Sciences.

Vincenzo De Maio is a Lecturer in Distributed Systems at the University of Leicester since June 2025 and a former postdoctoral researcher at the research unit of Computational Sustainability at TU Wien. He is co-Principal Investigator for TU Wien in the FFG funded project High-Performance integrated Quantum Computing (HPQC), Austria’s flagship project on High-Performance Quantum Computing. He has a strong research focus on hybrid quantum-classical systems, and his lecture on Hybrid Quantum-Classical Systems has been featured in the Atlas der Guten Lehre. He is an active contributor to the open-source ecosystem and his research explores scalable hybrid quantum-classical computing models.

Alessandro Tundo is a University Assistant for the Research Unit in Computational Sustainability at TU Wien. He received his Ph.D. in Computer Science with honors from the University of Milano-Bicocca in 2024. His research interests are in the intersection of distributed systems and software engineering, with a particular focus on energy-efficient self-adaptive systems operating in the cloud continuum.

Felix Zilk is a PhD student in the Research Unit Computational Sustainability at TU Wien. He holds a master’s degree (with honors) in Physics from the University of Vienna. Before joining TU Wien, he was a research assistant at the Christian Doppler Laboratory for Photonic Quantum Computers. His current research focuses on the compilation of quantum circuits and integrating quantum computers into classical and HPC systems.

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