# Exploring Entanglement Spectra and Phase Diagrams in Multi-Electron Quantum Dot Chains

## TL;DR

This paper studies how electron interactions and potential energy changes affect entanglement in quantum dot chains, revealing complex dynamics and phase transitions.

## Contribution

The novel contribution is identifying entanglement transitions and phase diagrams in multi-electron quantum dot systems under varying potential and interaction strengths.

## Key findings

- Local potential shifts and Coulomb interactions significantly redistribute electron configurations in quantum dot spin chains.
- Entanglement transitions become sharper and finite-size effects reduce as system size increases.
- Phase diagrams illustrate complex entanglement dynamics influenced by interdot interactions and potential energy adjustments.

## Abstract

We investigate the entanglement properties in semiconductor quantum dot systems modeled by the extended Hubbard model, focusing on the impacts of potential energy variations and electron interactions within a four-site quantum dot spin chain. Our study explores local and pairwise entanglement across configurations with electron counts N=4 and N=6, under different potential energy settings. By adjusting the potential energy in specific dots and examining the entanglement across various interaction regimes, we identify significant variations in the ground states of quantum dots. We extend this analysis to larger systems with L=6 and L=8, comparing electron counts N=L and N=L+2, revealing sharper entanglement transitions and reduced finite-size effects as the system size increases. Our results show that local potential shifts and the Coulomb interaction strength lead to notable redistributions of the electron configurations in the quantum dot spin chain, significantly affecting the entanglement properties. These changes are depicted in phase diagrams that highlight entanglements’ dependencies on the interaction strengths and potential energy adjustments, illustrating complex entanglement dynamics shifts triggered by interdot interactions.