Use of Electron Paramagnetic resonance (EPR) technique to build quantum computers: n-qubit (n=1,2,3,4) Toffoli Gates

TL;DR

This paper proposes a theoretical method using Electron Paramagnetic Resonance (EPR) with electron spins to construct multi-qubit Toffoli gates, enabling quantum computing, which is distinct from NMR-based approaches.

Contribution

It introduces a novel EPR-based technique for implementing multi-qubit Toffoli gates using exchange-coupled electron spins, unlike traditional NMR methods.

Findings

EPR can be used to set n-qubit configurations at resonance.

Construction of NOT, CNOT, and Toffoli gates with electron spins.

EPR-based gates are not feasible with NMR due to different coupling mechanisms.

Abstract

It is shown theoretically how to use the EPR (Electron Paramagnetic Resonance) technique, using electron spins as qubits, coupled with each other by the exchange interaction, to set the configuration of n qubits (n=1,2,3,4) at resonance, in conjunction with pulses, to construct the NOT (one qubit), CNOT (two qubits), CCNOT (three qubits), CCCNOT (four qubits) Toffoli gates, which can be exploited to build a quantum computer. This is unique to EPR, wherein exchange-coupled electron spins are used. This is not possible with NMR (Nuclear Magnetic Resonance), that uses nuclear spins as qubits, which do not couple with each other by the exchange interaction.