Thermal rectification in anharmonic chains under an energy-conserving noise

Area of Science:

• Thermodynamics
• Statistical Mechanics
• Condensed Matter Physics

Background:

• Thermal rectification, where heat flux depends on flow direction, is a phenomenon of significant theoretical and experimental interest.
• Existing theoretical models often predict the vanishing of thermal rectification in the thermodynamic limit, contradicting experimental observations.

Purpose of the Study:

• To demonstrate that thermal rectification can be restored in theoretical models by incorporating an energy-conserving noise mechanism.
• To show that this noise ensures the rectification effect persists in the thermodynamic limit.

Main Methods:

• Introduction of an energy-conserving noise with a specific rate (λ) that randomly flips particle velocities.
• Application of Langevin equations to model a classical harmonic chain with a quartic pinning potential (Φ(4) model) coupled to heat baths.

Main Results:

• The inclusion of energy-conserving noise successfully restores thermal rectification.
• The rectification effect remains finite in the thermodynamic limit as long as the noise rate (λ) is non-zero.

Conclusions:

• Energy-conserving noise is a crucial factor for observing finite thermal rectification in the thermodynamic limit.
• The Φ(4) model coupled via Langevin equations serves as a valid framework to illustrate this phenomenon.