# Completing the physical representation of quantum algorithms provides a retrocausal explanation of their speedup

@article{Castagnoli2016CompletingTP, title={Completing the physical representation of quantum algorithms provides a retrocausal explanation of their speedup}, author={Giuseppe Castagnoli}, journal={arXiv: Quantum Physics}, year={2016} }

In previous works, we showed that an optimal quantum algorithm can always be seen as a sum over classical histories in each of which the problem solver knows in advance one of the possible halves of the solution she will read in the future and performs the computation steps (oracle queries) still needed to reach it. Given an oracle problem, this retrocausal explanation of the speedup yields the order of magnitude of the number of oracle queries needed to solve it in an optimal quantum way…

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