Finite size mean-field models
Quantum Physics
2009-11-13 v1
Abstract
We characterize the two-site marginals of exchangeable states of a system of quantum spins in terms of a simple positivity condition. This result is used in two applications. We first show that the distance between two-site marginals of permutation invariant states on N spins and exchangeable states is of order 1/N. The second application relates the mean ground state energy of a mean-field model of composite spins interacting through a product pair interaction with the mean ground state energies of the components.
Cite
@article{arxiv.quant-ph/0605216,
title = {Finite size mean-field models},
author = {M. Fannes and C. Vandenplas},
journal= {arXiv preprint arXiv:quant-ph/0605216},
year = {2009}
}
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20 pages