Publication Details
Probabilistic storage and retrieval of qubit phase gates
Ziman Mário, doc. Mgr., Ph.D.
Probability, Quantum theory, Controlled-NOT gates, Failure Probability, Optimal Protocols, Priori Knowledge, Quantum Circuit, Quantum Dynamics, Storace and Retrievals, Unitari Transformations
Probabilisticstorage and retrieval (PSR) of unitary quantum dynamics is possible withexponentially small failure probability with respect to the number of systemsused as a quantum memory [PRL 122, 170502 (2019)]. Here we study improvementsdue to a priori knowledge about the unitary transformation to be stored. Inparticular, we study N -> 1 PSR of qubit phase gates, i.e. qubitrotations a round Z axis with an unknown angle, and show that if we accessthe gate only N-times, the optimal probability of perfect retrieving of itssingle use is N/(N+1). We propose a quantum circuit realization for theoptimal protocol and show that programmable phase gate [PRL 88, 047905 (2002)]can be turned into (2^k-1)-> 1 optimal PSR of phase gates and requires only k CNOT gates, whilehaving exponentially small failure probability in k.
@article{BUT168542,
author="Michal {Sedlák} and Mário {Ziman}",
title="Probabilistic storage and retrieval of qubit phase gates",
journal="Physical Review A",
year="2020",
volume="102",
number="1",
pages="1--8",
doi="10.1103/PhysRevA.102.032618",
issn="2469-9926",
url="https://journals.aps.org/pra/abstract/10.1103/PhysRevA.102.032618"
}