Spin State Transfer in Laterally Coupled Quantum Dot Chains with Disorders

TL;DR

This paper investigates how disorders like hyperfine interactions and exchange fluctuations affect quantum information transfer in quantum dot chains, finding anti-ferromagnetic chains are more resilient than ferromagnetic ones.

Contribution

It provides a comparative analysis of disorder effects on quantum dot chains and demonstrates the superior robustness of anti-ferromagnetic configurations.

Findings

Hyperfine interaction is more destructive than exchange fluctuations.

Anti-ferromagnetic chains are more resistant to disorders.

Time modulation improves transmission, especially in anti-ferromagnetic chains.

Abstract

Quantum dot arrays are a promising media for transferring quantum information between two distant points without resorting to mobile qubits. Here we study two most common disorders namely, hyperfine interaction and exchange coupling fluctuations, in quantum dot arrays and their effects on quantum communication through these chains. Our results show that the hyperfine interaction is more destructive than the exchange coupling fluctuations. The average optimal time for communication is not affected by any disorder in the system and our simulations show that anti-ferromagnetic chains are much more resistive than the ferromagnetic ones against both kind of disorders. Even when time modulation of a coupling and optimal control is employed to improve the transmission, the anti-ferromagnetic chain performs much better. We have assumed the quasi-static approximation for hyperfine interaction and time dependent fluctuations in the exchange couplings. Particularly, for studying exchange coupling fluctuations we have considered the static disorder, white noise and $1/f$ noise.