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arxiv: 0906.1663 · v3 · pith:EL7VAT34new · submitted 2009-06-09 · ❄️ cond-mat.stat-mech · quant-ph

Reduced density matrices and entanglement entropy in free lattice models

classification ❄️ cond-mat.stat-mech quant-ph
keywords entanglementdensityentropyfreehamiltonianmatricesreducedspectra
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We review the properties of reduced density matrices for free fermionic or bosonic many-particle systems in their ground state. Their basic feature is that they have a thermal form and thus lead to a quasi-thermodynamic problem with a certain free-particle Hamiltonian. We discuss the derivation of this result, the character of the Hamiltonian and its eigenstates, the single-particle spectra and the full spectra, the resulting entanglement and in particular the entanglement entropy. This is done for various one- and two-dimensional situations, including also the evolution after global or local quenches.

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