Thermal Critical Points and Quantum Critical End Point in the Frustrated Bilayer Heisenberg Antiferromagnet

ORAL

Abstract

We present a quantum Monte Carlo scheme for the simulation of frustrated quantum magnets that allows us to reduce or even eliminate the spin-problem for several dimerized quantum spin systems. We discuss in particular its application to the thermal properties of the spin-1/2 Heisenberg model on a frustrated square lattice bilayer. At zero temperature for the later model, a discontinuous quantum phase transition separates an interlayer singlet phase from an antiferromagnetic ground state formed by interlayer triplets. We show that this discontinuous transition extends up to finite temperatures and terminates in a quantum critical point. We identify this critical point as belonging to the Ising universality class, alert long-range order being absent at finite temperatures. We furthermore trace the discontinuous quantum phase transitions between the fully frustrated and the unfrustrated bilayer model using iPEPS tensor network methods. In particular, we identify a quantum critical end point that terminates the quantum critical line originating from the critical point of the unfrustrated bilayer system on the discontinuous transition line.

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Presenters

  • Stefan Wessel

    • Institut für Theoretische Festkörperphysik, RWTH Aachen University
    • RWTH Aachen University
    • Institute for Theoretical Solid State Physics, RWTH Aachen University

Authors

  • Jonas Stapmanns

    • RWTH Aachen University
    • Institut für Theoretische Festkörperphysik, RWTH Aachen University

  • Philippe Corboz

    • University of Amsterdam
    • Institute for Theoretical Physics, University of Amsterdam
    • Institute for Theoretical Physics and Delta Institute for Theoretical Physics, Universiteit van Amsterdam

  • Frederic Mila

    • EPFL Lausanne
    • Institute of Theoretical Physics, Ecole Polytechnique Fédérale Lausanne (EPFL)
    • Institute of Physics, École Polytechnique Fédérale de Lausanne
    • Institute of Physics, École Polytechnique Fédérale de Lausanne (EPFL)

  • Andreas Honecker

    • Universite de Cergy-Pontoise
    • Laboratoire de Physique Théorique et Modélisation, Cergy-Pontoise University
    • Laboratoire de Physique Théorique et Modélisation, Université de Cergy-Pontoise

  • Bruce Normand

    • Paul Scherrer Institute, Switzerland
    • Paul Scherrer Institute
    • Neutrons and Muons Research Division, Paul Scherrer Institute
    • Paul Scherer Institute, Vilingen
    • Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland

  • Stefan Wessel

    • Institut für Theoretische Festkörperphysik, RWTH Aachen University
    • RWTH Aachen University
    • Institute for Theoretical Solid State Physics, RWTH Aachen University