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DY: Fachverband Dynamik und Statistische Physik
DY 6: Critical Phenomena and Phase Transitions
DY 6.6: Vortrag
Montag, 17. März 2025, 12:45–13:00, H47
Study of the de Almeida-Thouless (AT) line in the one-dimensional diluted power-law XY spin glass — •Ramana Bharadwaj Vedula — IISER Bhopal, Bhopal, India
The behavior of finite-dimensional spin glasses at low temperatures has been debated for decades, with the replica symmetry breaking (RSB) and droplet pictures offering competing explanations. This work investigates the Almeida-Thouless (AT) line in the one-dimensional power-law diluted XY spin glass model, where interactions decay as 1/r2σ. Tuning σ emulates dimensional changes, bridging mean-field and non-mean-field regimes.
A novel heatbath algorithm was developed to efficiently equilibrate XY spins at low temperatures. Using this, we studied phase transitions for σ = 0.6 (<2/3), where clear evidence for an AT line exists, and for σ = 0.75, 0.85 (>2/3), where the evidence weakens. Interestingly, data for σ = 0.75 and σ = 0.85 suggest finite-size effects mimic RSB-like behavior, but analysis aligns with the droplet picture.
Unlike traditional approaches, we also varied the magnetic field at fixed temperature, providing unique insights into spin glass properties. Our results show that the AT line disappears as σ increases, favoring the droplet model for low-dimensional spin glasses.
Keywords: Spin glass; Droplet Theory; Replica Symmetry Breaking; AT line; Monte-Carlo