# Density Functional Theory of Composite Fermions

## TL;DR

This paper develops a density functional theory tailored for two-dimensional electron systems in strong magnetic fields, especially near even-denominator filling factors, to analyze fractional quantum Hall states influenced by external potentials.

## Contribution

It introduces a systematic and rigorous density functional framework for composite fermion liquids in fractional quantum Hall regimes, including a method for practical functional approximation.

## Key findings

- Provides a theoretical foundation for ground state properties in fractional quantum Hall systems.
- Offers a practical approach to constructing approximate density functionals.
- Enhances understanding of composite fermion behavior under external potentials.

## Abstract

We construct a density functional theory for two-dimension electron (hole) gases subjected to both strong magnetic fields and external potentials. In particular, we are focused on regimes near even-denominator filling factors, in which the systems form composite fermion liquids. Our theory provides a systematic and rigorous approach to determine the properties of ground states in fractional quantum Hall regime modified by artificial structures. We also propose a practical way to construct approximated functional.