Diffusion in interacting two-dimensional systems under a uniform magnetic field

TL;DR

This study investigates how magnetic fields influence particle diffusion in two-dimensional interacting fermionic systems at high temperature, revealing that strong interactions can suppress magnetic effects on transport.

Contribution

We demonstrate that the fermionic truncated Wigner approximation effectively models diffusion dynamics in 2D systems under magnetic fields, validated against Lanczos benchmarks, and explore the interplay of interactions and magnetic flux.

Findings

Strong interactions suppress magnetic-field effects on diffusion.

Magnetic flux reduces diffusion when interactions are comparable to kinetic energy.

Finite-size effects are minimal for systems larger than 400 sites.

Abstract

The dynamics of interacting particles in orbital magnetic fields are notoriously difficult to study, as this physics is inherently connected to electronic correlations in two-dimensional systems, for which no straightforward theoretical methods are available. Here, we report on the diffusive relaxation dynamics of two-dimensional interacting fermionic systems under a uniform magnetic field in the infinite temperature regime. We first show that the fermionic truncated Wigner approximation captures the equilibration dynamics unexpectedly well for intermediate interaction strengths when going beyond one dimension. This high accuracy holds at least for relatively small ladder systems, which are accessible to the Lanczos method that we use to benchmark the reliability of the Wigner approximation. We find that strong interactions, which exceed the hopping energy, suppress magnetic-field effects on diffusive transport. However, when the interactions are comparable to the kinetic energy, the diffusion is significantly reduced by the magnetic flux. This is observed for sufficiently large systems (above approximately 400 lattice sites), where finite-size effects weakly affect particle transport. We suggest that our results should be directly accessible on current optical lattice platforms.