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Main Authors: Hering, Dag-Björn, Walther, Matthias R., Schmidt, Kai P., Uhrig, Götz S.
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2405.13768
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author Hering, Dag-Björn
Walther, Matthias R.
Schmidt, Kai P.
Uhrig, Götz S.
author_facet Hering, Dag-Björn
Walther, Matthias R.
Schmidt, Kai P.
Uhrig, Götz S.
contents We apply continuous similarity transformations (CSTs) to study the zero-temperature breakdown of long-range ordered quantum antiferromagnets. The CST flow equations are truncated in momentum space by the scaling dimension so that all operators with scaling dimension up to two are taken into account. We determine the quantum phase transition out of the Néel-ordered phase in the unfrustrated square lattice Heisenberg bilayer as well as the quantum melting of the Néel-ordered and columnar phase in the highly frustrated $J_1$-$J_2$ model on the square lattice. In all cases the CST is set up to isolate the ground state so that the stability of the flow equations, the ground-state energy, and the sublattice magnetization are used to explore the long-range ordered phases. We extract quantum-critical points which agree well with values in the literature. Further, we estimate the associated critical exponents $α$ and $β$ which turns out to be a challenging task for the CST approach.
format Preprint
id arxiv_https___arxiv_org_abs_2405_13768
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Quantum melting of long-range ordered quantum antiferromagnets investigated by momentum-space continuous similarity transformations
Hering, Dag-Björn
Walther, Matthias R.
Schmidt, Kai P.
Uhrig, Götz S.
Strongly Correlated Electrons
We apply continuous similarity transformations (CSTs) to study the zero-temperature breakdown of long-range ordered quantum antiferromagnets. The CST flow equations are truncated in momentum space by the scaling dimension so that all operators with scaling dimension up to two are taken into account. We determine the quantum phase transition out of the Néel-ordered phase in the unfrustrated square lattice Heisenberg bilayer as well as the quantum melting of the Néel-ordered and columnar phase in the highly frustrated $J_1$-$J_2$ model on the square lattice. In all cases the CST is set up to isolate the ground state so that the stability of the flow equations, the ground-state energy, and the sublattice magnetization are used to explore the long-range ordered phases. We extract quantum-critical points which agree well with values in the literature. Further, we estimate the associated critical exponents $α$ and $β$ which turns out to be a challenging task for the CST approach.
title Quantum melting of long-range ordered quantum antiferromagnets investigated by momentum-space continuous similarity transformations
topic Strongly Correlated Electrons
url https://arxiv.org/abs/2405.13768