Control of a two-electron quantum ring with an external magnetic field

TL;DR

This paper explores how external time-dependent magnetic fields can be used to control quantum states in a two-electron quantum ring, enabling manipulation of singlet-triplet transitions for quantum information applications.

Contribution

It demonstrates a method to control quantum states in a two-electron quantum ring using magnetic field switching, highlighting the role of hyperfine interactions and degeneracy points.

Findings

Magnetic field switching induces singlet-triplet transitions.

Optimal field values and timescales for control are identified.

Control efficiency depends on the speed of magnetic field variation.

Abstract

We investigate the use of external time-dependent magnetic field for the control of the quantum states in a two-electron quantum ring. The hyperfine interaction of the confined electrons with surrounding nuclei couples the singlet state with the three triplet states. When the external magnetic field is changed, the singlet ground state becomes degenerate with the triplet states allowing singlet-triplet transitions. By choosing different speeds for the magnetic field switching the final quantum state of the system can be manipulated. We evaluate suitable magnetic field values and time scales for efficient quantum ring control.