Quantum computing with single electron bubbles in helium

TL;DR

This paper proposes a novel quantum computing platform using single electron bubbles in liquid helium, leveraging their long coherence times and controllable spin states for multi-qubit operations.

Contribution

It introduces a new physical system for quantum computing based on electron spins in helium bubbles, including initialization, manipulation, and readout schemes.

Findings

Electron spins in helium bubbles have long coherence times.

A method for initializing and controlling multiple qubits is proposed.

Potential for scalable quantum registers using linear RF traps.

Abstract

An electron inside liquid helium forms a bubble of 17 \AA in radius. In an external magnetic field, the two-level system of a spin 1/2 electron is ideal for the implementation of a qubit for quantum computing. The electron spin is well isolated from other thermal reservoirs so that the qubit should have very long coherence time. By confining a chain of single electron bubbles in a linear RF quadrupole trap, a multi-bit quantum register can be implemented. All spins in the register can be initialized to the ground state either by establishing thermal equilibrium at a temperature around 0.1 K and at a magnetic field of 1 T or by sorting the bubbles to be loaded into the trap with magnetic separation. Schemes are designed to address individual spins and to do two-qubit CNOT operations between the neighboring spins. The final readout can be carried out through a measurement similar to the Stern-Gerlach experiment.