An electrically-driven single-atom `flip-flop' qubit

Abstract

The spins of atoms and atom-like systems are among the most coherent objects in which to store quantum information. However, the need to address them using oscillating magnetic fields hinders their integration with quantum electronic devices. Here we circumvent this hurdle by operating a single-atom 'flip-flop' qubit in silicon, where quantum information is encoded in the electronnuclear states of a phosphorus donor. The qubit is controlled using local electric fields at microwave frequencies, produced within a metal-oxide-semiconductor device. The electrical drive is mediated by the modulation of the electron-nuclear hyperfine coupling, a method that can be extended to many other atomic and molecular systems. These results pave the way to the construction of solidstate quantum processors where dense arrays of atoms can be controlled using only local electric fields.

Semiconductor spin qubits

“…VII). Basic operation of the flip-flop qubit has been demonstrated by Savytskyy et al, 2022. An alternative coupling relevant to donors is the magnetic dipole-dipole coupling between electrons, as its long-range, magnetic nature avoids the atomic precision fabrication requirement for exchange. Proposals to exploit this interaction through isotopic engineering and implanted donors employ a variety of methods to manage the interaction, including selective ionization and mechanical motion (Hill et al, 2015;Ladd et al, 2002;O'Gorman et al, 2016;de Sousa et al, 2004), however execution of any such proposal will require devices with exquisite coherence.…”