Non-local propagation of correlations in quantum systems with long-range interactions

By Philip Richerme, Zhexuan Gong, Aaron C. Lee, C. Senko, Jacob W. Smith, M. Foss-Feig, Spyridon Michalakis, Alexey V. Gorshkov, Christopher R. Monroe. Nature, 2014

658 citations recorded by the source corpus.

The maximum speed with which information can propagate in a quantum many-body system directly affects how quickly disparate parts of the system can become correlated and how difficult the system will be to describe numerically. For systems with only short-range interactions, Lieb and Robinson derived a constant-velocity bound that limits correlations to within a linear effective ‘light cone’. However, little is known about the propagation speed in systems with long-range interactions, because analytic solutions rarely exist and because the best long-range bound is too loose to accurately describe the relevant dynamical timescales for any known spin model. Here we apply a variable-range Ising spin chain Hamiltonian and a variable-range XY spin chain Hamiltonian to a far-from-equilibrium quantum many-body system and observe its time evolution. For several different interaction ranges, we determine the spatial and time-dependent correlations, extract the shape of the light cone and measure the velocity with which correlations propagate through the system. This work opens the possibility for studying a wide range of many-body dynamics in quantum systems that are otherwise intractable.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/150d580d9990dcdf7fe0bc24455ac2aab0b66c87

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Dynamical Purification Phase Transition Induced by Quantum Measurements (2019, background): “[34] P.”
Quantum thermalization through entanglement in an isolated many-body system (2016, background): “The approximately linear rise at early times (Figure 3 inset) is related to the spreading of entanglement in the system within an effective light cone [2, 31, 32].”
Quantum metrology with nonclassical states of atomic ensembles (2016, methodology): “Ising spin-spin couplings have been implemented in a linear Paul trap with up to ∼20 ions (Islam et al., 2013; Jurcevic et al., 2014; Richerme et al., 2014) and in a Penning trap forming a 2D Coulomb crystal of ∼200 ions (Britton et al.”
Observing the Space- and Time-Dependent Growth of Correlations in Dynamically Tuned Synthetic Ising Models with Antiferromagnetic Interactions (2017, background): “Finite propagation speeds for correlations and other signals are well explored in the context of sudden quench protocols with constant postquench Hamiltonians [18,20,23,47,48], but their importance for state-preparation protocols (with a time-dependent Hamiltonian) is not equally well known (see App”