In this paper an alternative version of the quantum phase estimation is proposed, in which the Hadamard gates at the beginning are substituted by a quantum Fourier transform. This new circuit coincides with the original one, when the ancilla is initialized with ∣0⟩. With the help of a projection-based tensor decomposition and closed-form expressions of its exponential, this new method can be interpreted as a multiplier coupled to the Hamiltonian of the corresponding target unitary operator. Based on this observation a recursive decomposition is derived.
@article{arxiv.2303.05894,
title = {An Alternative Formulation of the Quantum Phase Estimation Using Projection-Based Tensor Decompositions},
author = {Marian Stengl},
journal= {arXiv preprint arXiv:2303.05894},
year = {2024}
}