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Phys. Rev. Lett. 93, 140402 (2004) [4 pages]

Locality in Quantum and Markov Dynamics on Lattices and Networks

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M. B. Hastings*
T-13, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

Received 28 May 2004; published 28 September 2004

We consider gapped systems governed by either quantum or Markov dynamics, with the low-lying states below the gap being approximately degenerate. For a broad class of dynamics, we prove that ground or stationary state correlation functions can be written as a piece decaying exponentially in space plus a term set by matrix elements between the low-lying states. The key to the proof is a local approximation to the negative energy, or annihilation, part of an operator in a gapped system. Applications to numerical simulation of quantum systems and to networks are discussed.

© 2004 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.93.140402
DOI:
10.1103/PhysRevLett.93.140402
PACS:
05.30.–d, 03.67.Lx

*Electronic address: hastings@cnls.lanl.gov