We provide exact analytical solutions for the problem of time-optimal transfer of coherence from one spin-polarization to a threefold coherence in a trilinear Ising chain with a fixed energy available and subject to local controls with a non-negligible time cost. The time of transfer is optimal and consistent with a previous numerical result obtained assuming instantaneous local controls.

• Received 24 September 2012

DOI:https://doi.org/10.1103/PhysRevA.86.054302