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

M. Cheneau, P. Barmettler, D. Poletti, M. Endres, P. Schauss, T. Fukuhara, C. Gross, I. Bloch, C. Kollath, S. Kuhr

Research output: Contribution to journalLetter

438 Citations (Scopus)

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.
LanguageEnglish
Pages484-487
Number of pages4
JournalNature
Volume481
Issue number7382
Early online date25 Jan 2012
DOIs
Publication statusPublished - 26 Jan 2012

Fingerprint

cones
propagation
condensed matter physics
information theory
quantum computation
quenching
engineering
gases
interactions

Keywords

  • atoms
  • insulator
  • lattice systems
  • dynamics
  • lieb-robinson bounds
  • light-cone-like
  • spreading
  • correlations
  • quantum
  • many-body system

Cite this

Cheneau, M., Barmettler, P., Poletti, D., Endres, M., Schauss, P., Fukuhara, T., ... Kuhr, S. (2012). Light-cone-like spreading of correlations in a quantum many-body system. Nature, 481(7382), 484-487. https://doi.org/10.1038/nature10748
Cheneau, M. ; Barmettler, P. ; Poletti, D. ; Endres, M. ; Schauss, P. ; Fukuhara, T. ; Gross, C. ; Bloch, I. ; Kollath, C. ; Kuhr, S. / Light-cone-like spreading of correlations in a quantum many-body system. In: Nature. 2012 ; Vol. 481, No. 7382. pp. 484-487.
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Cheneau, M, Barmettler, P, Poletti, D, Endres, M, Schauss, P, Fukuhara, T, Gross, C, Bloch, I, Kollath, C & Kuhr, S 2012, 'Light-cone-like spreading of correlations in a quantum many-body system' Nature, vol. 481, no. 7382, pp. 484-487. https://doi.org/10.1038/nature10748

Light-cone-like spreading of correlations in a quantum many-body system. / Cheneau, M.; Barmettler, P.; Poletti, D.; Endres, M.; Schauss, P.; Fukuhara, T.; Gross, C.; Bloch, I.; Kollath, C.; Kuhr, S.

In: Nature, Vol. 481, No. 7382, 26.01.2012, p. 484-487.

Research output: Contribution to journalLetter

TY - JOUR

T1 - Light-cone-like spreading of correlations in a quantum many-body system

AU - Cheneau, M.

AU - Barmettler, P.

AU - Poletti, D.

AU - Endres, M.

AU - Schauss, P.

AU - Fukuhara, T.

AU - Gross, C.

AU - Bloch, I.

AU - Kollath, C.

AU - Kuhr, S.

PY - 2012/1/26

Y1 - 2012/1/26

N2 - 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 observedexperimentally. 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.

AB - 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 observedexperimentally. 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.

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Cheneau M, Barmettler P, Poletti D, Endres M, Schauss P, Fukuhara T et al. Light-cone-like spreading of correlations in a quantum many-body system. Nature. 2012 Jan 26;481(7382):484-487. https://doi.org/10.1038/nature10748