Creating a superposition of unknown quantum states
Michał Oszmaniec , Andrzej Grudka , Michał Horodecki , Antoni Wójcik
AbstractThe superposition principle is one of the landmarks of quantum mechanics. The importance of quantum superpositions provokes questions about the limitations that quantum mechanics itself imposes on the possibility of their generation. In this work, we systematically study the problem of the creation of superpositions of unknown quantum states. First, we prove a no-go theorem that forbids the existence of a universal probabilistic quantum protocol producing a superposition of two unknown quantum states. Second, we provide an explicit probabilistic protocol generating a superposition of two unknown states, each having a fixed overlap with the known referential pure state. The protocol can be applied to generate coherent superposition of results of independent runs of subroutines in a quantum computer. Moreover, in the context of quantum optics it can be used to efficiently generate highly nonclassical states or non- Gaussian states.
|Journal series||Physical Review Letters, ISSN 0031-9007, (A 45 pkt)|
|Publication size in sheets||0.5|
|Score|| = 45.0, 20-12-2017, ArticleFromJournal|
= 45.0, 20-12-2017, ArticleFromJournal
|Publication indicators||: 2016 = 8.462 (2) - 2016=7.805 (5)|
* presented citation count is obtained through Internet information analysis and it is close to the number calculated by the Publish or Perish system.