Dresden 2026 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 60: Critical Phenomena and Phase Transitions
DY 60.3: Vortrag
Freitag, 13. März 2026, 10:00–10:15, ZEU/0114
Hardness of the "swap" spin glass ensemble — •Alexander K. Hartmann1, Leticia Cugliandolo2, and Marco Tarzia2 — 1University of Oldenburg, Germany — 2Sorbonne University, Paris, France
The “swap” ensemble [1] consist of spin glasses with quenched interaction constants Jij, where the spins si=σiτi with σi=± 1 and τi ∈ [1−/Δ/2,1+Δ/2] exhibit varying lengths τi. The value Δ=0 corresponds to the standard Ising case. Inspired by “swap moves” used for simulating structural classes [2], it was observed [1] that when including swaps τi ↔ τj within Monte Carlo simulations at finite temperature with annealing T→ 0, ground states are easier to find. The actual “swap” ensemble samples consist of the bonds Jij=Jijτiτj obtained at the end of the annealing, respectively. Here, we study for two-dimensional spin glasses, by applying exact ground-state algorithms [3], the probability p0 that true ground states have been found in the annealing. This allows us to define the hardness of the bond samples. In particular we consider the results as a function of the total number tMC of annealing steps and length variation Δ. Furthermore, by applying domain-wall energy calculations [3], we investigate for various values of Δ and slow annealing (p0→ 1) whether the {Jij} samples actually behave like spin glasses or rather like ferromagnets.
[1] A. Mirando, L. Cugliandolo and M. Tarzia, Phys. Rev. E 100, L043301 (2024).
[2] L. Berthier and D. R. Reichman, Nat. Rev. Phys. 5, 102 (2023).
[3] A.K. Hartmann and A.P. Young, Phys. Rev. B 64, 180404 (2001).
Keywords: spin glasses; ground states; Monte Carlo simulations; annealing; ferromagnets