Nonlinearity-Induced Fractional Thouless Pumping of Solitons.

Area of Science:

• Condensed matter physics
• Nonlinear dynamics
• Topological physics

Background:

• Fractional transport phenomena, like fractional Thouless pumping, are typically linked to non-trivial topology in energy bands.
• Soliton transport in nonlinear systems is a key area of research with potential applications.

Purpose of the Study:

• To investigate the occurrence of fractional Thouless pumping of solitons in a nonlinear system.
• To explore the role of nonlinearity in inducing topological phenomena.

Main Methods:

• Utilized a nonlinear off-diagonal Aubry-André-Harper model.
• Analyzed the behavior of solitons under parameter variations.
• Investigated the topological properties of the system's energy bands.

Main Results:

• Demonstrated fractional Thouless pumping of solitons in a system with topologically trivial linear energy bands.
• Observed soliton pumping across one unit cell over one, two, three, or four periods.
• Showed average displacements of 1, 1/2, 1/3, or 1/4 unit cells per cycle.
• Attributed the phenomenon to nonlinearity-induced changes in on-site potentials.

Conclusions:

• Nonlinearity can induce fractional Thouless pumping even in the absence of topologically non-trivial linear energy bands.
• The findings highlight a new mechanism for achieving fractional transport.
• The proposed model is implementable on current photonic platforms.