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SWAP Test for an Arbitrary Number of Quantum States

Quantum Physics 2021-10-27 v1 Data Structures and Algorithms

Abstract

We develop a recursive algorithm to generalize the quantum SWAP test for an arbitrary number mm of quantum states requiring O(m)O(m) controlled-swap (CSWAP) gates and O(logm)O(\log m) ancillary qubits. We construct a quantum circuit able to simultaneously measure overlaps of mm arbitrary pure states. Our construction relies on a pairing unitary that generates a superposition state where every pair of input states is labelled by a basis state formed by the ancillaries.

Keywords

Cite

@article{arxiv.2110.13261,
  title  = {SWAP Test for an Arbitrary Number of Quantum States},
  author = {Xavier Gitiaux and Ian Morris and Maria Emelianenko and Mingzhen Tian},
  journal= {arXiv preprint arXiv:2110.13261},
  year   = {2021}
}