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Quantum Monte Carlo simulations in the trimer basis: first-order transitions and thermal critical points in frustrated trilayer magnets

by L. Weber, A. Honecker, B. Normand, P. Corboz, F. Mila, S. Wessel

This Submission thread is now published as

Submission summary

Authors (as registered SciPost users): Philippe Corboz · Andreas Honecker · Lukas Weber
Submission information
Preprint Link:  (pdf)
Code repository:
Date accepted: 2022-01-06
Date submitted: 2021-10-25 09:53
Submitted by: Weber, Lukas
Submitted to: SciPost Physics
Ontological classification
Academic field: Physics
  • Condensed Matter Physics - Computational
Approaches: Theoretical, Computational


The phase diagrams of highly frustrated quantum spin systems can exhibit first-order quantum phase transitions and thermal critical points even in the absence of any long-ranged magnetic order. However, all unbiased numerical techniques for investigating frustrated quantum magnets face significant challenges, and for generic quantum Monte Carlo methods the challenge is the sign problem. Here we report on a general quantum Monte Carlo approach with a loop-update scheme that operates in any basis, and we show that, with an appropriate choice of basis, it allows us to study a frustrated model of coupled spin-1/2 trimers: simulations of the trilayer Heisenberg antiferromagnet in the spin-trimer basis are sign-problem-free when the intertrimer couplings are fully frustrated. This model features a first-order quantum phase transition, from which a line of first-order transitions emerges at finite temperatures and terminates in a thermal critical point. The trimer unit cell hosts an internal degree of freedom that can be controlled to induce an extensive entropy jump at the quantum transition, which alters the shape of the first-order line. We explore the consequences for the thermal properties in the vicinity of the critical point, which include profound changes in the lines of maxima defined by the specific heat. Our findings reveal trimer quantum magnets as fundamental systems capturing in full the complex thermal physics of the strongly frustrated regime.

Author comments upon resubmission

Dear Editor,

Thank you very much for forwarding the second round of referee reports for our manuscript "Quantum Monte Carlo simulations in the trimer basis: first-order transitions and thermal critical points in frustrated trilayer magnets." Thank you in advance for your further consideration of our contribution.

Best regards,

Lukas Weber, Andreas Honecker, Bruce Normand, Philippe Corboz, Frédéric Mila and Stefan Wessel

List of changes

We have addressed the two suggestions by the new referee (i) in a direct response and (ii) in the revised manuscript. Indeed these points help to improve the quality of the manuscript, which we resubmit here.

Published as SciPost Phys. 12, 054 (2022)

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