Out-of-Equilibrium Clock Model at the Verge of Criticality

Area of Science:

• Statistical Mechanics
• Condensed Matter Physics
• Non-equilibrium Thermodynamics

Background:

• The equilibrium clock model exhibits three phases: ordered, quasiliquid, and disordered, with two phase transitions.
• Out-of-equilibrium systems with broken spatial symmetry and thermal equilibrium can act as thermal machines.

Purpose of the Study:

• To investigate an out-of-equilibrium lattice model of 2D discrete rotators.
• To quantify the system's susceptibility to thermodynamic forces driving it out of equilibrium.
• To identify optimal operating conditions for enhanced thermal machine performance.

Main Methods:

• Modeling a 2D discrete rotator lattice in contact with heat reservoirs at different temperatures.
• Introducing and studying a dynamical response function to measure susceptibility.
• Analyzing the system's behavior around critical temperatures.

Main Results:

• The out-of-equilibrium model demonstrates directed rotation of spin variables, functioning as a thermal machine.
• Optimal performance is achieved near the critical temperature between the ordered and quasiliquid phases.
• The system exhibits heightened susceptibility to external thermodynamic forces at this critical point.

Conclusions:

• Critical fluctuations in systems of interacting motors can be leveraged to improve dynamic and thermodynamic performance.
• Exploiting proximity to phase transitions is key for efficient thermal machine operation.
• This research highlights the potential of non-equilibrium systems as functional thermal machines.