Quantum multi-level wavelet transforms

The classical wavelet transform has been widely applied in the information processing field. It implies that quantum wavelet transform (QWT) may play an important role in quantum information processing. In this paper, we present the iteration equations of the general QWT using generalized tensor product. Then, Haar QWT (HQWT), Daubechies D4 QWT (DQWT), and their inverse transforms are proposed respectively. Meanwhile, the circuits of the two kinds of multi-level HQWT are designed. What's more, the multi-level HQWT based on the periodization extension is implemented for the first time. The complexity analysis shows that the proposed multi-level QWTs on 2(n) elements can be implemented by O(n(3)) basic operations. Simulation experiments demonstrate that the proposed QWTs are correct and effective. (C) 2019 Elsevier Inc. All rights reserved.