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Two-site entropy and quantum phase transitions in low-dimensional models

Ö. Legeza·J. Sólyom
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Abstract

We propose a new approach to study quantum phase transitions in low-dimensional lattice models. It is based on studying the von Neumann entropy of two neighboring central sites in a long chain. It is demonstrated that the procedure works equally well for fermionic and spin models, and the two-site entropy is a better indicator of quantum phase transition than calculating gaps, order parameters or the single-site entropy. The method is especially convenient when the density-matrix renormalization-group (DMRG) algorithm is used.

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Ö. Legeza, J. Sólyom. 2006-02-16. Two-site entropy and quantum phase transitions in low-dimensional models. https://doi.org/10.1103/physrevlett.96.116401

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