Net motion induced by nonantiperiodic vibratory or electrophoretic excitations with zero time average.

Area of Science:

• Physics
• Mechanical Engineering
• Colloid Science

Background:

• Oscillatory excitations with temporal asymmetry can induce net drift.
• Previous studies focused on point particles, nonlinear optics, and quantum systems.
• Macroscopic mechanical motion has not been widely explored in this context.

Purpose of the Study:

• To experimentally demonstrate net motion in macroscopic objects using temporally asymmetric force excitations.
• To investigate the impact of specific oscillatory waveforms on mechanical systems.
• To explore facile control of object motion using tunable periodic driving forces.

Main Methods:

• Utilizing two experimental systems: vibrating surfaces with solid objects and oscillating electric fields with charged colloidal particles.
• Employing nonantiperiodic, two-mode sinusoidal excitations with odd and even frequency ratios (e.g., 2Hz and 3Hz).
• Conducting both experimental observations and numerical simulations.

Main Results:

• Observed net motion in both macroscopic solid objects and charged colloidal particles.
• Demonstrated that the direction of motion is consistent for a given waveform and reversible by altering the waveform's sign.
• Validated experimental findings through numerical simulations.

Conclusions:

• Temporally asymmetric oscillatory forces can effectively control the motion of macroscopic objects.
• The observed phenomenon is applicable to various nonlinear mechanical systems.
• This work provides a foundation for facile manipulation of objects using tunable periodic driving forces.