Quantum optimal control
= Quantum optimal control
{title2=$J=\Phi(\rho(T))+\int_0^T\ell(f(t))\,dt$}
<Quantum optimal control> minimizes a state-transfer, observable, or gate error together with resource costs, subject to a controlled <Schrödinger equation> or <Lindblad equation>. Forward propagation of the state and backward propagation of a <costate> compute the <gradient> efficiently. The optimum depends on the admissible time-dependent fields and laboratory constraints.