Quantum Computing Algorithms and Computational Complexity (Hardback or Cased Book)

This Special Issue is mainly concerned with quantum algorithms, their mathematics from behind and the complexity issues arising from them. It comprises seven papers: Two of them are focused on improving the performance by means of quantum algorithms over the best instances of classical ones: "A Fast Quantum Image Component Labeling Algorithm" [1] by Yan Li, Dapeng Hao, Yang Xu and Kinkeung Lai. "Quantum Algorithms for Some Strings Problems Based on Quantum String Comparator" [2] by Kamil Khadiev, Artem Ilikaev and Jevgenijs Vihrovs. Another four papers deal with enhanced quantum algorithms: "Progress towards Analytically Optimal Angles in Quantum Approximate Optimisation" [3] by Daniil Rabinovich, Richik Sengupta, Ernesto Campos, Vishwanathan Akshay and Jacob Biamonte. "Quantum Weighted Fractional Fourier Transform" [4] by Tieyu Zhao, Tianyu Yang and Yingying Chi. "On the Amplitude Amplification of Quantum States Corresponding to the Solutions of the Partition Problem" [5] by Mauro Mezzini, Jose J. Paulet, Fernando Cuartero, Hernan I. Cruz and Fernando L. Pelayo. "On the Complexity of Finding the Maximum Entropy Compatible Quantum State" [6] by Serena Di Giorgio and Paulo Mateus. Last, but not least, one paper researched a classical operational research problem by means of quantum annealing: "GPS: A New TSP Formulation for Its Generalizations Type QUBO" [7] by Saul Gonzalez-Bermejo, Guillermo Alonso-Linaje and Parfait Atchade-Adelomou. As Guest Editors of this Special Issue, we would like to thank the authors and reviewers who made this possible by promoting, spreading research on and supporting quantum computing.