Qubits as edge state detectors: illustration using the SSH model

TL;DR

This paper proposes using qubits as detectors for topological edge states in the SSH model, demonstrating how qubit dynamics reveal the presence or absence of edge states, which are robust against noise.

Contribution

It introduces a novel method for detecting topological edge states using qubits interacting with an SSH chain, linking qubit dynamics to topological properties.

Findings

Qubit dynamics vary significantly with the presence of edge states.

The method provides a way to detect edge states via qubit measurements.

Edge states are shown to be robust against environmental noise.

Abstract

As is well known, qubits are the fundamental building blocks of quantum computers, and more generally, of quantum information. A major challenge in the development of quantum devices arises because the information content in any quantum state is rather fragile, as no system is completely isolated from its environment. Generally, such interactions degrade the quantum state, resulting in a loss of information. Topological edge states are promising in this regard because they are in ways more robust against noise and decoherence. But creating and detecting edge states can be challenging. We describe a composite system consisting of a two-level system (the qubit) interacting with a finite Su-Schrieffer-Heeger chain (a hopping model with alternating hopping parameters) attached to an infinite chain. In this model, the dynamics of the qubit changes dramatically depending on whether or not an edge state exists. Thus, the qubit can be used to determine whether or not an edge state exists in this model.