### Abstract

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.

Original language | English |
---|---|

Pages (from-to) | 484-487 |

Number of pages | 4 |

Journal | Nature |

Volume | 481 |

Issue number | 7382 |

Early online date | 25 Jan 2012 |

DOIs | |

Publication status | Published - 26 Jan 2012 |

### Fingerprint

### Keywords

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

### Cite this

*Nature*,

*481*(7382), 484-487. https://doi.org/10.1038/nature10748

}

*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.

Research output: Contribution to journal › Letter

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.

KW - atoms

KW - insulator

KW - lattice systems

KW - dynamics

KW - lieb-robinson bounds

KW - light-cone-like

KW - spreading

KW - correlations

KW - quantum

KW - many-body system

U2 - 10.1038/nature10748

DO - 10.1038/nature10748

M3 - Letter

VL - 481

SP - 484

EP - 487

JO - Nature

JF - Nature

SN - 0028-0836

IS - 7382

ER -