Light-cone-like spreading of correlations in a quantum many-body system

By M. Cheneau, P. Barmettler, Dario Poletti, M. Endres, P. Schauss, Takeshi Fukuhara, C. Gross, I. Bloch, C. Kollath, S. Kuhr. Nature, 2011

647 citations recorded by the source corpus.

In relativistic quantum field theory, information propagation is bounded by the speed of light. No such limit exists in the non-relativistic case, although in real physical systems, short-range interactions may be expected to restrict the propagation of information to finite velocities. The question of how fast correlations can spread in quantum many-body systems has been long studied. The existence of a maximal velocity, known as the Lieb–Robinson bound, has been shown theoretically to exist in several interacting many-body systems (for example, spins on a lattice)—such systems can be regarded as exhibiting an effective light cone that bounds the propagation speed of correlations. The existence of such a ‘speed of light’ has profound implications for condensed matter physics and quantum information, but has not been observed experimentally. Here we report the time-resolved detection of propagating correlations in an interacting quantum many-body system. By quenching a one-dimensional quantum gas in an optical lattice, we reveal how quasiparticle pairs transport correlations with a finite velocity across the system, resulting in an effective light cone for the quantum dynamics. Our results open perspectives for understanding the relaxation of closed quantum systems far from equilibrium, and for engineering the efficient quantum channels necessary for fast quantum computations.

Subfields: Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/f309a07ff0624818bc308cfc5e1881fd284f7e26

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In Atomic and Molecular Physics, and Optics

Citations in the corpus

Quantum speed limits: from Heisenberg’s uncertainty principle to optimal quantum control (2017, background): “This behaviour was recently verified experimentally in [278], while the analysis for long range interactions, where such bounds can be violated is found in [118].”
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Microscopic Control and Detection of Ultracold Strontium in Optical-Tweezer Arrays (2018, background): “[7] Marc Cheneau, Peter Barmettler, Dario Poletti, Manuel Endres, Peter Schausz, Takeshi Fukuhara, Christian”
Single-atom imaging of fermions in a quantum-gas microscope (2015, background): “2e), has a FWHM of 630(10) nm, close to the diffraction-limited resolution of the microscope objective (Fig.”
Observing the Space- and Time-Dependent Growth of Correlations in Dynamically Tuned Synthetic Ising Models with Antiferromagnetic Interactions (2017, background): “Such bounds are well explored in the context of quench dynamics [18, 20, 23, 44, 45], but their importance for state preparation protocols is not equally well known (see Appendix E for a brief review on LiebRobinson bounds adapted for the present context).”
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