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Quasiparticle engineering and entanglement propagation in a quantum many-body system

2014; Nature Portfolio; Volume: 511; Issue: 7508 Linguagem: Inglês

10.1038/nature13461

1476-4687

Petar Jurcevic, B. P. Lanyon, Philipp Hauke, Cornelius Hempel, P. Zoller, R. Blatt, C. F. Roos,

Cold Atom Physics and Bose-Einstein Condensates

The fine control afforded by trapped atomic ions is used to explore experimentally how the range of interactions between the ions influences the spreading of information in quantum many-body systems. The speed at which information propagates in quantum many-body systems determines the overall behaviour of these systems. If the interactions between the system components are short-ranged, the dynamics are well understood and relatively straightforward to compute. Less clear is what happens when long-range interactions are present. Now two groups have used the exquisite control afforded by trapped atomic ions to explore experimentally how the interaction range influences the time evolution of quantum many-body systems. The key to explaining and controlling a range of quantum phenomena is to study how information propagates around many-body systems. Quantum dynamics can be described by particle-like carriers of information that emerge in the collective behaviour of the underlying system, the so-called quasiparticles1. These elementary excitations are predicted to distribute quantum information in a fashion determined by the system’s interactions2. Here we report quasiparticle dynamics observed in a quantum many-body system of trapped atomic ions3,4. First, we observe the entanglement distributed by quasiparticles as they trace out light-cone-like wavefronts5,6,7,8,9,10,11. Second, using the ability to tune the interaction range in our system, we observe information propagation in an experimental regime where the effective-light-cone picture does not apply7,12. Our results will enable experimental studies of a range of quantum phenomena, including transport13,14, thermalization15, localization16 and entanglement growth17, and represent a first step towards a new quantum-optic regime of engineered quasiparticles with tunable nonlinear interactions.