Levialdi shrinking operator QAOA QSZK-completeness QUBO TSP VRP amplitude amplification combinatorial optimization computational efficiency image component labeling local operator maximum von Neumann entropy n/a quantum Fourier transform quantum Markov chains quantum algorithm quantum algorithms quantum annealing quantum circuit optimization quantum computation quantum computing quantum image processing quantum weighted fractional Fourier transform sorting string processing subset sum problem thema EDItEUR::G Reference, Information and Interdisciplinary subjects::GP Research and information: general thema EDItEUR::P Mathematics and Science variatonal algorithms