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

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Cheneau, M. and Barmettler, P. and Poletti, D. and Endres, M. and Schauss, P. and Fukuhara, T. and Gross, C. and Bloch, I. and Kollath, C. and Kuhr, S. (2012) Light-cone-like spreading of correlations in a quantum many-body system. Nature, 481 (7382). pp. 484-487. ISSN 0028-0836 (https://doi.org/10.1038/nature10748)

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Abstract

In relativistic quantum field theory, information propagation is bounded by the speed of light. No such limit exists in the nonrelativistic 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 lattice2–5)—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.

ORCID iDs

Cheneau, M., Barmettler, P., Poletti, D., Endres, M., Schauss, P., Fukuhara, T., Gross, C., Bloch, I., Kollath, C. and Kuhr, S. ORCID logoORCID: https://orcid.org/0000-0001-8386-5357;
  • Item type:Article
    ID code:40155
    Dates:
    Date
    Event
    26 January 2012
    Published
    25 January 2012
    Published Online
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:21 Jun 2012 14:43
    Last modified:15 Dec 2024 05:32
    URI:https://strathprints.strath.ac.uk/id/eprint/40155
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