TY  - JOUR
AU  - Lam, Manolo R.
AU  - Peter, Natalie
AU  - Groh, Thorsten
AU  - Alt, Wolfgang
AU  - Robens, Carsten
AU  - Meschede, Dieter
AU  - Negretti, Antonio
AU  - Montangero, Simone
AU  - Calarco, Tommaso
AU  - Alberti, Andrea
TI  - Demonstration of Quantum Brachistochrones between Distant States of an Atom
JO  - Physical review / X
VL  - 11
IS  - 1
SN  - 2160-3308
CY  - College Park, Md.
PB  - APS
M1  - FZJ-2022-01871
SP  - 011035
PY  - 2021
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000620021000001
DO  - DOI:10.1103/PhysRevX.11.011035
UR  - https://juser.fz-juelich.de/record/907162
ER  -