Berezinskii-Kosterlitz-Thouless Paired Phase in Coupled XY Models

Giacomo Bighin, Nicolò Defenu, I. Nándori, Luca Salasnich, Andrea Trombettoni

Research output: Contribution to journalArticle

1 Citation (Scopus)


We study the effect of a linear tunneling coupling between two-dimensional systems, each separately exhibiting the topological Berezinskii-Kosterlitz-Thouless (BKT) transition. In the uncoupled limit, there are two phases: one where the one-body correlation functions are algebraically decaying and the other with exponential decay. When the linear coupling is turned on, a third BKT-paired phase emerges, in which one-body correlations are exponentially decaying, while two-body correlation functions exhibit power-law decay. We perform numerical simulations in the paradigmatic case of two coupled XY models at finite temperature, finding evidences that for any finite value of the interlayer coupling, the BKT-paired phase is present. We provide a picture of the phase diagram using a renormalization group approach.

Original languageEnglish
Article number100601
JournalPhysical review letters
Issue number10
Publication statusPublished - Sep 3 2019

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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