Quantum Computation with Aharonov-Bohm Qubits

TL;DR

This paper explores the use of Aharonov-Bohm flux in mesoscopic rings as a basis for qubits, detailing how auxiliary levels enable fundamental quantum gate operations, with proposed realizations in quantum dot and vacancy structures.

Contribution

It introduces a novel qubit implementation using mesoscopic rings with Aharonov-Bohm flux and auxiliary levels for quantum gate operations, including specific physical realization proposals.

Findings

Auxiliary levels enable all fundamental quantum gates.

Proposed realization in quantum dots or vacancy structures.

Feasibility of using Aharonov-Bohm flux for qubit control.

Abstract

We analyze the posibility of employing the mesoscopic-nanoscopic ring of a normal metal in a doubly degenerate persistent current state with a third auxihilary level and in the presence of the Aharonov-Bohm flux equal to the half of the normal flux quantum $\hbar c/e$ as a qubit. The auxiliary level can be effectively used for all fundamental quantum logic gate (qu-gate) operations which includes the initialization, phase rotation, bit flip and the Hadamard transformation as well as the double-qubit controlled operations (conditional bit flip). We suggest a tentative realization of the mechanism as either the mesoscopic structure of three quantum dots coherently coupled by mesoscopic tunnelling in crossed magnetic and electric fields, or as a nanoscopic structure of triple anionic vacancy (similar to $F_3$ centers in alkali halides) with one trapped electron in one spin projection state.