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arXiv · 2405.03751

Limits to velocity of signal propagation in many-body systems: a quantum-information perspective

Piotr Wysocki·Jan Chwedeńczuk
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Abstract

The Lieb-Robinson bound (LRB) states that the range and strength of interactions between the constituents of a complex many-body system impose upper limits to how fast the signal can propagate. It manifests in a light cone-like growth of correlation function connecting two distant subsystems. Here we employ the techniques of quantum information to demonstrate that the LRB can be determined from local measurements performed on a single qubit that is connected to a many-body system. This formulation provides an operational recipe for estimating the LRB in complex systems, replacing the measurement of the correlation function with simple single-particle manipulations. We demonstrate the potency of this approach by deriving the upper limit to the speed of signal propagation in the XY spin chain.

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Piotr Wysocki, Jan Chwedeńczuk. 2024-05-06. Limits to velocity of signal propagation in many-body systems: a quantum-information perspective. https://arxiv.org/abs/2405.03751

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