K. S. Chernova

A. Stepanenko

M. A. Gorlach

We achieve maximal-fidelity state transfer in the fastest possible time for a 3-qubit chain by applying the quantum variational method.

Quantum processors need to be able to transfer quantum states quickly and reliably. Using the quantum brachistochrone approach, we derive an exact protocol to transfer a single-particle state across a three-qubit chain by tuning the hopping rates between qubits. Our analytic solution achieves high-fidelity transfer in the shortest possible time, offering insights for optimal transfer solutions in long qubit chains.

Quantum brachistochrone method has recently emerged as a technique allowing one to implement the desired unitary evolution operator in a physical system within the minimal time. Here, we apply this approach to the problem of time-optimal quantum state transfer in the array of three qubits with time-varying nearest-neighbor couplings and analytically derive the fastest protocol.

Three-qubit shortcut

Optimizing state transfer in a three-qubit array via quantum brachistochrone method