Qubits as edge state detectors: illustration using the SSH model

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.

Statistics tuned entanglement of the boundary modes in coupled Su-Schrieffer-Heeger chains

“…This emergent few-particle quantum mechanics of the novel boundary modes is extremely rich and forms the essential ingredient for estimating the usefulness as candidates for material realisation of quantum computing [12][13][14][15][16][17][18] where such boundary modes serve as qubits [19][20][21].…”

“…Theoretical studies examining such boundary modes in coupled-wire systems [22][23][24][25], their tunability in junctions [13,20,26] and attempts to entangle them non-trivially are been vigorously pursued in this regard [13,19,20,[27][28][29]. The complementary issue at the experimental front of controlled manipulation and tuning of such boundary modes are also being currently explored in wide variety of different materials [14,[30][31][32][33][34][35][36][37][38] as well as in cold atom systems [39][40][41][42][43].…”