Multiband Fractional Thouless Pumps

Area of Science:

• Condensed matter physics
• Topological physics
• Quantum mechanics

Background:

• Quantization of particle transport is fundamental to topological physics.
• Thouless pumps, simplified integer quantum Hall effect models, exhibit quantization governed by single-band Wannier state winding.

Purpose of the Study:

• To investigate the effect of repulsive interactions on Thouless pump quantization.
• To explore the possibility of achieving fractional quantization in Thouless pumps.

Main Methods:

• Numerical simulations of few-particle systems.
• Application of a dynamical Hartree-Fock ansatz.

Main Results:

• Repulsive interactions drive a transition from integer to fractional quantization in Thouless pumps.
• Stabilization of multiband Wannier states with fractional winding.
• The dynamical Hartree-Fock ansatz accurately reproduces the pumping phase diagram.

Conclusions:

• Repulsive interactions offer a mechanism to realize fractional-quantized Thouless pumps.
• Multiband Wannier states with fractional winding are key to this transition.
• The used theoretical framework is capable of describing these interacting topological systems.