douglas mesquita - Academia.edu (original) (raw)

douglas mesquita

Uploads

Papers by douglas mesquita

Research paper thumbnail of Anomalous Quantum-Critical Scaling Corrections in Two-Dimensional Antiferromagnets

Physical Review Letters, 2018

We study the Néel-paramagnetic quantum phase transition in two-dimensional dimerized S = 1/2 Heis... more We study the Néel-paramagnetic quantum phase transition in two-dimensional dimerized S = 1/2 Heisenberg antiferromagnets using finite-size scaling of quantum Monte Carlo data. We resolve the long standing issue of the role of cubic interactions arising in the bond-operator representation when the dimer pattern lacks a certain symmetry. We find non-monotonic (monotonic) size dependence in the staggered (columnar) dimerized model, where cubic interactions are (are not) present. We conclude that there is a new irrelevant field in the staggered model, but, at variance with previous claims, it is not the leading irrelevant field. The new exponent is ω2 ≈ 1.25 and the prefactor of the correction L −ω 2 is large and comes with a different sign from that of the conventional correction with ω1 ≈ 0.78. Our study highlights competing scaling corrections at quantum critical points.

Research paper thumbnail of Anomalous Quantum-Critical Scaling Corrections in Two-Dimensional Antiferromagnets

Physical Review Letters, 2018

We study the Néel-paramagnetic quantum phase transition in two-dimensional dimerized S = 1/2 Heis... more We study the Néel-paramagnetic quantum phase transition in two-dimensional dimerized S = 1/2 Heisenberg antiferromagnets using finite-size scaling of quantum Monte Carlo data. We resolve the long standing issue of the role of cubic interactions arising in the bond-operator representation when the dimer pattern lacks a certain symmetry. We find non-monotonic (monotonic) size dependence in the staggered (columnar) dimerized model, where cubic interactions are (are not) present. We conclude that there is a new irrelevant field in the staggered model, but, at variance with previous claims, it is not the leading irrelevant field. The new exponent is ω2 ≈ 1.25 and the prefactor of the correction L −ω 2 is large and comes with a different sign from that of the conventional correction with ω1 ≈ 0.78. Our study highlights competing scaling corrections at quantum critical points.

Log In