How to probe the microscopic onset of irreversibility with ultracold atoms

Stochastic modeling of spreading and dissipation in mixed-chaotic systems that are driven quasistatically

We analyze energy spreading for a system that features mixed chaotic phase space, whose control parameters (or slow degrees of freedom) vary quasistatically. For demonstration purpose we consider the restricted three-body problem, where the distance between the two central stars is modulated due to their Kepler motion. If the system featured hard chaos, one would expect diffusive spreading with coefficient that can be estimated using linear-response (Kubo) theory. But for mixed phase space the chaotic sea is multilayered. Consequently, it becomes a challenge to find a robust procedure that translates the sticky dynamics into a stochastic model. We propose a Poincaré-sequencing method that reduces the multidimensional motion into a one-dimensional random walk in impact space. We test the implied relation between stickiness and the rate of spreading.