First-order phase transitions in the real microcanonical ensemble

Area of Science:

• * Computational Physics
• * Statistical Mechanics
• * Materials Science

Background:

• * First-order phase transitions are crucial in various physical systems.
• * Understanding transition barriers is key to predicting material behavior.
• * Traditional simulations often use the canonical ensemble, which may overestimate barriers.

Purpose of the Study:

• * To develop and validate a simulation technique for first-order phase transitions.
• * To investigate the properties of the microcanonical ensemble for phase transitions.
• * To establish a framework for creating tailored ensembles for phase transition studies.

Main Methods:

• * Simulation using the real microcanonical ensemble (constant total energy).
• * Application to droplet condensation-evaporation in a Lennard-Jones system (up to 2048 particles).
• * Employed Metropolis-like sampling with a replica-exchange scheme.

Main Results:

• * The microcanonical ensemble simulation revealed significantly lower transition barriers.
• * Demonstrated a lower barrier compared to the canonical ensemble counterpart.
• * Developed a general framework for ensemble evaluations by separating system and ensemble properties.

Conclusions:

• * The microcanonical ensemble offers a more accurate depiction of phase transition barriers.
• * The developed framework enables the design of artificial ensembles for specific phase transition investigations.
• * This technique provides a valuable tool for studying phenomena like condensation and evaporation.