CMOS Position-Based Charge Qubits: Theoretical Analysis of Control and Entanglement

TL;DR

This paper provides a theoretical framework for position-based charge qubits in CMOS technology, analyzing their control, interaction, and entanglement properties in scalable quantum computing architectures.

Contribution

It introduces a first-principles tight-binding model for charge qubits, including interaction effects and entanglement mechanisms, tailored for CMOS-compatible quantum devices.

Findings

Charge qubits can be entangled via electrostatic interaction.

A comprehensive model for multi-qubit systems is developed.

The formalism includes calculations of localized Wannier functions and Hamiltonian entries.

Abstract

In this study, a formal definition, robustness analysis and discussion on the control of a position-based semiconductor charge qubit are presented. Such a qubit can be realized in a chain of coupled quantum dots, forming a register of charge-coupled transistor-like devices, and is intended for CMOS implementation in scalable quantum computers. We discuss the construction and operation of this qubit, its Bloch sphere, and relation with maximally localized Wannier functions which define its position-based nature. We then demonstrate how to build a tight-binding model of single and multiple interacting qubits from first principles of the Schr\"odinger formalism. We provide all required formulae to calculate the maximally localized functions and the entries of the Hamiltonian matrix in the presence of interaction between qubits. We use three illustrative examples to demonstrate the electrostatic interaction of electrons and discuss how to build a model for many-electron (qubit) system. To conclude this study, we show that charge qubits can be entangled through electrostatic interaction.