Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

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 J_ij, where the spins s_i=σ_iτ_i with σ_i=± 1 and τ_i ∈ [1−/Δ/2,1+Δ/2] exhibit varying lengths τ_i. 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 τ_i ↔ τ_j 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 J_ij=J_ijτ_iτ_j 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 t_MC 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 {J_ij} 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