An impurity-induced gap system as a quantum data bus for quantum state transfer

TL;DR

This paper proposes a quantum data bus based on an impurity-induced energy gap in a tight-binding chain, enabling high-fidelity, long-distance quantum state transfer with robustness against disorder.

Contribution

It introduces a novel impurity-based quantum data bus that achieves perfect quantum state transfer and demonstrates its robustness through analytical and numerical analysis.

Findings

Energy gap induced by impurity enables state transfer

High-fidelity transfer over long distances

Robustness against coupling disorder

Abstract

We introduce a tight-binding chain with a single impurity to act as a quantum data bus for perfect quantum state transfer. Our proposal is based on the weak coupling limit of the two outermost quantum dots to the data bus. First show that the data bus has an energy gap between the ground and first-excited states in the single-particle case induced by the impurity in the single particle case. By connecting two quantum dots to two sites of the data bus, the system can accomplish a high-fidelity and long-distance quantum state transfer. Numerical simulations were performed for a finite system; the results show that the numerical and analytical results of the effective coupling strength agree well with each other. Moreover, we study the robustness of this quantum communication protocol in the presence of disorder in the couplings between the nearest-neighbor quantum dots. We find that the gap of the system plays an important role in robust quantum state transfer.