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arXiv · 2001.10079

Multicriticality in a one-dimensional topological band insulator

Mariana Malard·David Brandao·Paulo Eduardo de Brito·Henrik Johannesson
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Abstract

A central tenet in the theory of quantum phase transitions (QPTs) is that a nonanalyticity in the ground-state energy in the thermodynamic limit implies a QPT. Here we report on a finding that challenges this assertion. As a case study we take a phase diagram of a one-dimensional band insulator with spin-orbit coupled electrons, supporting trivial and topological gapped phases separated by intersecting critical surfaces. The intersections define multicritical lines across which the ground-state energy becomes nonanalytical, concurrent with a closing of the band gap, but with no phase transition taking place.

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Mariana Malard, David Brandao, Paulo Eduardo de Brito, Henrik Johannesson. 2020-01-27. Multicriticality in a one-dimensional topological band insulator. https://doi.org/10.1103/physrevresearch.2.033246

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