Fundamental description of Wannier qubits of any topology in semiconductor by analytical and numerical computations

TL;DR

This paper provides a detailed analytical and numerical foundation for modeling Wannier qubits of arbitrary topology in semiconductors, bridging Schroedinger and tight-binding models, and exploring dissipation and localization effects.

Contribution

It introduces two methods to derive tight-binding models from Schroedinger equations and extends the framework to multi-electron and higher-dimensional systems.

Findings

Tight-binding model justified from Schroedinger formalism for various topologies.

Dissipation processes emerge during nanowire bending in classical and quantum regimes.

Wavepacket localization occurs due to nanowire bending.

Abstract

Justification of tight-binding model from Schroedinger formalism for various topologies of position-based semiconductor qubits is presented in this work. Simplistic tight-binding model allows for description of single-electron devices at large integration scale. However it is due to the fact that tight-binding model omits the integro-differential equations that arise from electron-electron interaction in Schroedinger model. Two approaches are given in derivation of tight-binding model from Schroedinger equation. First approach is conducted by usage of Green functions obtained from Schroedinger equation. Second approach is given by usage of Taylor expansion applied to Schroedinger equation. The obtained results can be extended for the case of many Wannier qubits with more than one electron and can be applied to 2 and 3 dimensional model. Furthermore various correlation functions are proposed in Schroedinger formalism that can account for static and time-dependent electric and magnetic field polarizing given Wannier qubit system. One of the central results of presented work relies on the emergence of dissipation processes during smooth bending of semiconductor nanowires both in the case of classical and quantum picture. Presented results give the base for physical description of electrostatic Q-Swap gate of any topology using open loop nanowires. We observe strong localization of wavepacket due to nanowire bending.