%0 Journal Article
%A Lam, Manolo R.
%A Peter, Natalie
%A Groh, Thorsten
%A Alt, Wolfgang
%A Robens, Carsten
%A Meschede, Dieter
%A Negretti, Antonio
%A Montangero, Simone
%A Calarco, Tommaso
%A Alberti, Andrea
%T Demonstration of Quantum Brachistochrones between Distant States of an Atom
%J Physical review / X
%V 11
%N 1
%@ 2160-3308
%C College Park, Md.
%I APS
%M FZJ-2022-01871
%P 011035
%D 2021
%X Transforming an initial quantum state into a target state through the fastest possible route—a quantum brachistochrone—is a fundamental challenge for many technologies based on quantum mechanics. In two-level systems, the quantum brachistochrone solutions are long known. These solutions, however, are not applicable to larger systems, especially when the target state cannot be reached through a local transformation. Here, we demonstrate fast coherent transport of an atomic wave packet over a distance of 15 times its size—a paradigmatic case of quantum processes going beyond the two-level system. Our measurements of the transport fidelity reveal the existence of a minimum duration—a quantum speed limit—for the coherent splitting and recombination of matter waves. We obtain physical insight into this limit by relying on a geometric interpretation of quantum state dynamics. These results shed light on a fundamental limit of quantum state dynamics and are expected to find relevant applications in quantum sensing and quantum computing.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000620021000001
%R 10.1103/PhysRevX.11.011035
%U https://juser.fz-juelich.de/record/907162