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Efficient Quantum Monte Carlo simulations of highly frustrated magnets: the frustrated spin-1/2 ladder
by Stefan Wessel, B. Normand, Frédéric Mila, Andreas Honecker
This Submission thread is now published as
Submission summary
| Authors (as registered SciPost users): | Andreas Honecker · Frédéric Mila |
| Submission information | |
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| Preprint Link: | http://arxiv.org/abs/1704.01973v2 (pdf) |
| Date submitted: | 2017-06-19 02:00 |
| Submitted by: | Honecker, Andreas |
| Submitted to: | SciPost Physics |
| Ontological classification | |
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| Academic field: | Physics |
| Specialties: |
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| Approach: | Computational |
Abstract
Quantum Monte Carlo simulations provide one of the more powerful and versatile numerical approaches to condensed matter systems. However, their application to frustrated quantum spin models, in all relevant temperature regimes, is hamstrung by the infamous "sign problem." Here we exploit the fact that the sign problem is basis-dependent. Recent studies have shown that passing to a dimer (two-site) basis eliminates the sign problem completely for a fully frustrated spin model on the two-leg ladder. We generalize this result to all partially frustrated two-leg spin-1/2 ladders, meaning those where the diagonal and leg couplings take any antiferromagnetic values. We find that, although the sign problem does reappear, it remains remarkably mild throughout the entire phase diagram. We explain this result and apply it to perform efficient quantum Monte Carlo simulations of frustrated ladders, obtaining accurate results for thermodynamic quantities such as the magnetic specific heat and susceptibility of ladders up to L=200 rungs (400 spins 1/2) and down to very low temperatures.
Author comments upon resubmission
List of changes
1) Comment on the use of periodic boundary conditions added at the end of section 3.3 (P10).
2) Remark on "logarithmic singularity" in the low-temperature limit of the susceptibility in Fig. 12(b) moved (section 4.5, P17).
3) "matrix-element effects" moved to a different position in the sentence (section 4.5, P17).
Published as SciPost Phys. 3, 005 (2017)