Magnetic alteration of entanglement in two-electron quantum dots

TL;DR

This paper investigates how magnetic fields influence quantum entanglement in two-electron quantum dots, revealing a discontinuous entanglement behavior and proposing a method to estimate it via addition energy measurements.

Contribution

It provides an analytical expression for entanglement in noninteracting electrons and explores symmetry breaking effects in entanglement variation under magnetic fields.

Findings

Entanglement is discontinuous with magnetic field strength.

Analytical expression matches numerical results for certain states.

Proposes a new method to estimate entanglement from addition energy.

Abstract

Quantum entanglement is analyzed thoroughly in the case of the ground and lowest states of two-electron axially symmetric quantum dots under a perpendicular magnetic field. The individual-particle and the center-of-mass representations are used to study the entanglement variation at the transition from interacting to noninteracting particle regimes. The mechanism of symmetry breaking due to the interaction, that results in the states with symmetries related to the later representation only, being entangled even at the vanishing interaction, is discussed. The analytical expression for the entanglement measure based on the linear entropy is derived in the limit of noninteracting electrons. It reproduces remarkably well the numerical results for the lowest states with the magnetic quantum number M>2 in the interacting regime. It is found that the entanglement of the ground state is a discontinuous function of the field strength. A method to estimate the entanglement of the ground state, characterized by the quantum number M, with the aid of the magnetic field dependence of the addition energy is proposed.