Entanglement propagation in long-range Ising spin chains & 20 qubit entangled states.
We report on the observation of magnon quasiparticle dynamics in a one-dimensional many-body quantum system of trapped ions representing
an Ising spin model. Using the ability to tune the effective interaction range, and to prepare and measure the quantum state at the individual particle level, we
observe new quasiparticle phenomena. For the first time, we reveal the entanglement distributed by quasiparticles around a many-body system. Second, for long range interactions we observe the divergence of quasiparticle velocity and breakdown of the light-cone picture that is valid for short-range interactions. Our results will allow experimental studies of a wide range of phenomena, such as quantum transport, thermalization, localization and entanglement growth, and represent
a first step towards a new quantum-optical regime with on-demand quasi-particles with tunable non-linear interactions. We also present new results on using these interactions to generate entangled states with up to 20 spins
Host: Chris Monroe