# First-Principles Design of Qubits in Charged Carbon Nanomaterials

## TL;DR

This paper shows how carbon nanomaterials can be used to create stable qubits for quantum computing, with properties that remain consistent across a range of temperatures.

## Contribution

The study introduces a universal criterion for qubit feasibility in carbon nanostructures and demonstrates their thermal stability and scalability.

## Key findings

- Certain electron configurations in carbon nanomaterials maintain stable HOMO + LUMO occupancy across a wide temperature range.
- A universal criterion EHOMO + ELUMO = 2EFermi determines qubit feasibility in diverse carbon nanostructures.
- Carbon nanomaterials offer thermal stability and dimensional adaptability for practical quantum computing.

## Abstract

Our first-principles calculations have unveiled a profound influence of varied external charges on the energy levels and spin distributions of zero-, one-, and two-dimensional carbon nanomaterials. By leveraging the Fermi distribution formula, we systematically analyze the temperature-dependent electron occupancy probabilities of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO). Notably, configurations with specific additional electron loads exhibit a stable total occupancy of HOMO + LUMO equal to 1 across a wide temperature range, forming a robust basis for orbital qubits. This stability persists even under Fermi energy corrections, demonstrating minimal temperature sensitivity up to 300 K. Furthermore, we identify a universal criterion—EHOMO + ELUMO = 2EFermi—that governs qubit feasibility across diverse carbon nanostructures, independent of dimensionality or atom count. Experimental validation via charge injection methods (e.g., gate modulation or electron beam irradiation) is supported by existing precedents in carbon-based quantum devices. Our findings establish low-dimensional carbon nanomaterials as versatile, scalable platforms for quantum computing, combining thermal stability and dimensional adaptability, thus bridging theoretical insights with practical quantum engineering.