Discrete breathers assist energy transfer to ac-driven nonlinear chains

Area of Science:

• Condensed Matter Physics
• Nonlinear Dynamics
• Statistical Mechanics

Background:

• Understanding energy transport in nonlinear systems is crucial for materials science and device engineering.
• Anharmonic potentials significantly influence energy localization and transport dynamics in discrete systems.

Purpose of the Study:

• To numerically investigate energy transfer efficiency in a 1D particle chain with hard and soft anharmonic on-site potentials.
• To explore the role of discrete breathers (DBs) in mediating energy transfer from an external AC-driven particle.

Main Methods:

• Numerical calculation of energy source power for a 1D harmonically coupled particle chain.
• Analysis of systems with sixth-order polynomial on-site potentials (hard and soft anharmonicity).
• Investigation of system response to AC driving force with varying amplitude (A) and frequency (ω).

Main Results:

• Normalized energy transfer depends on driving frequency relative to the phonon band edges and anharmonicity type.
• Hard anharmonicity leads to increased normalized power near the upper phonon band edge with increasing amplitude.
• Soft anharmonicity shows increased normalized power near the lower phonon band edge with increasing amplitude.
• Movable discrete breathers (DBs) are observed, with frequencies above (hard) or below (soft) the phonon band.
• Quasiperiodic emission of DBs near resonance enhances energy transfer.

Conclusions:

• Discrete breathers play a significant role in facilitating energy transfer from an AC-driven particle to the 1D chain.
• The type of anharmonicity and driving conditions dictate the efficiency and mechanism of energy transfer.
• This work provides insights into nonlinear energy transport mechanisms relevant to advanced materials and devices.