Bulg. J. Phys. vol.48 no.2 (2021), pp. 174-182

Qubits, Decoherence and Edge State Detection: Illustration Using the SSH Model

M. Zaimi1, C. Boudreault2, N. Baspin3, H. Eleuch4, R. MacKenzie5, M. Hilke3
1Centre de Recherches Mathématiques, Université de Montréal, C.P. 6128, succursale Centre-ville, Montréal, QC H3C 3J7, Canada
2Département des sciences de la nature, Collége militaire royal de Saint-Jean, 15 Jacques-Cartier Nord, Saint-Jean-sur-Richelieu, QC Canada, J3B 8R8
3Department of Physics, McGill University, Montrélal, QC, Canada, H3A 2T8
4Department of Applied Sciences and Mathematics, College of Arts and Sciences, Abu Dhabi University, Abu Dhabi, UAE
5Département de physique, Université de Montréal, Complexe des Sciences, C.P. 6128, succursale Centre-ville, Montréal, QC,
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.

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