Spin-based quantum computing using electrons on liquid helium

TL;DR

This paper proposes using electron spins on liquid helium as qubits for quantum computing, highlighting their long coherence times and methods for implementing quantum gates.

Contribution

It introduces a novel approach to quantum computing with electron spins on liquid helium, emphasizing reduced decoherence and practical gate operations.

Findings

Coherence times for electron spins on helium can exceed 100 seconds.

Electrostatically held and manipulated electrons on helium are feasible for quantum computing.

A controlled-NOT operation can be achieved via magnetic dipole-dipole interaction.

Abstract

Numerous physical systems have been proposed for constructing quantum computers, but formidable obstacles stand in the way of making even modest systems with a few hundred quantum bits (qubits). Several approaches utilize the spin of an electron as the qubit. Here it is suggested that the spin of electrons floating on the surface of liquid helium will make excellent qubits. These electrons can be electrostatically held and manipulated much like electrons in semiconductor heterostructures, but being in a vacuum the spins on helium suffer much less decoherence. In particular, the spin orbit interaction is reduced so that moving the qubits with voltages applied to gates has little effect on their coherence. Remaining sources of decoherence are considered and it is found that coherence times for electron spins on helium can be expected to exceed 100 s. It is shown how to obtain a controlled-NOT operation between two qubits using the magnetic dipole-dipole interaction.