Spinodal-assisted nucleation in the two-dimensional q-state Potts model with short-to-long-range interactions

Area of Science:

• Statistical Mechanics
• Condensed Matter Physics
• Computational Physics

Background:

• Homogeneous nucleation is a fundamental process in phase transitions.
• The q-state Potts model describes systems with discrete states and interactions.
• Understanding nucleation in systems with varying interaction ranges is crucial.

Purpose of the Study:

• To investigate homogeneous nucleation in the 2D q-state Potts model.
• To analyze the crossover between compact droplet and spinodal-assisted nucleation regimes.
• To compare simulation results with field theoretical predictions for long-range interactions.

Main Methods:

• Monte Carlo simulations using heat bath dynamics.
• Inducing metastability via magnetic field quench in the low-temperature phase.
• Adjusting quench depth to maintain constant nucleation time across varying parameters (q, T, R).

Main Results:

• Identified a crossover from compact droplet nucleation (short-range interactions) to spinodal-assisted nucleation (long-range interactions).
• Spinodal scaling behavior was confirmed for interaction ranges R≳8-10.
• Signatures of a pseudospinodal singularity were observed for interaction ranges as small as R∼4-5.

Conclusions:

• The study elucidates the transition in nucleation mechanisms driven by interaction range.
• Spinodal-assisted nucleation becomes dominant at longer interaction ranges.
• Early indications of spinodal influence on nucleation are present even at moderate interaction ranges.