Southwest Quantum Information and Technology

Exploring the emergence of classical nonlinear dynamics with an atomic feedback-based architecture

Presenting Author: Manuel Munoz-Arias, University of New Mexico CQuIC
Contributing Author(s): Pablo Poggi, Ivan Deutsch

We propose a feedback-based protocol for the time evolution of the collective spin in an ultracold atomic ensemble. The protocol consists of a measurement process which yields information about the z-component of the collective spin, followed by an unitary part which is conditioned on the value of the measurement outcome. We study, an intermediate regime, where the measurement is strong enough to keep the spin wavepacket localized, but not so strong that measurement backaction dominates the dynamics. In that regime, we see the emergence of nonlinear dynamics in individual quantum trajectories. As a particular example, we show how this protocol allow us to recover the well known nonlinear kicked top, a paradigm of quantum chaos. We develop an analytical description of the resulting dynamics under the Gaussian approximation, and explicitly show how the regular, mixed and chaotic features of the kicked top phase space emerge from the noisy dynamics as the size of the ensemble increases. We finally characterize the chaotic dynamics by means of time series analysis and study the corresponding Lyapunov exponents.

(Session 5 : Sunday from 5:00pm - 7:00pm)