Speaker
Description
Quantum-chaotic dynamics in mixed phase space can enhance metrological sensitivity through mechanisms governed by global homoclinic structures. Building on a semiclassical formulation of the quantum Fisher information, we show that global homoclinic manifolds provide a practical guide to the most sensitive initial states. These manifolds organize transport near edge-of-chaos boundaries into channels with distinct accumulated responses to perturbations of the estimated parameter. Wavepackets placed on suitable channel boundaries can therefore exhibit strongly enhanced quantum Fisher information. For the quantum kicked top, we present numerical evidence that initial states selected on global homoclinic manifolds can approach Heisenberg-limited scaling with respect to both spin size and evolution time.