Quantum Circuit Optimization by Hadamard Gate Reduction

  • Nabila Abdessaied
  • Mathias Soeken
  • Rolf Drechsler
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8507)


Due to its fault-tolerant gates, the Clifford+T library consisting of Hadamard (denoted by H), T, and CNOT gates has attracted interest in the synthesis of quantum circuits. Since the implementation of T gates is expensive, recent research is aiming at minimizing the use of such gates. It has been shown that T-depth optimizations can be implemented efficiently for circuits consisting only of T and CNOT gates and that H gates impede the optimization significantly.

In this paper, we investigate the role of H gates in reducing the T-count and T-depth for quantum circuits. To reduce the number of H gates, we propose several algorithms targeting different steps in the synthesis of reversible functions as quantum circuits.

Experiments show the effect of H gate reductions on the costs for T-count and T-depth. Our approach yields a significant improvement of up to 88% in the final T-depth compared to the best known T-depth optimization technique.


Boolean Function Quantum Circuit Quantum Gate Target Line CNOT Gate 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  • Nabila Abdessaied
    • 2
  • Mathias Soeken
    • 1
    • 2
  • Rolf Drechsler
    • 1
    • 2
  1. 1.Institute of Computer ScienceUniversity of BremenGermany
  2. 2.Cyber-Physical SystemsDFKI GmbHBremenGermany

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