Hyperfine induced spin and entanglement dynamics in Double Quantum Dots: A homogeneous coupling approach

TL;DR

This paper provides an exact theoretical analysis of hyperfine-induced spin and entanglement dynamics in double quantum dots with homogeneous coupling, revealing decoherence times consistent with experiments.

Contribution

It introduces an approximation-free, exact solution for the model with homogeneous hyperfine couplings, advancing understanding of spin dynamics in quantum dots.

Findings

Exact solution for homogeneous hyperfine coupling case

Decoherence time matches experimental data

Short-time spin dynamics characterized

Abstract

We investigate hyperfine induced electron spin and entanglement dynamics in a system of two quantum dot spin qubits. We focus on the situation of zero external magnetic field and concentrate on approximation-free theoretical methods. We give an exact solution of the model for homogeneous hyperfine coupling constants (with all coupling coefficients being equal) and varying exchange coupling, and we derive the dynamics therefrom. After describing and explaining the basic dynamical properties, the decoherence time is calculated from the results of a detailed investigation of the short time electron spin dynamics. The result turns out to be in good agreement with experimental data.