Description du projet
Des nanotubes de carbone pour tester l’intrication quantique à grande échelle
Les nanotubes de carbone constituent un excellent hôte pour les qubits de spin en raison de leurs propriétés électroniques uniques et de leur capacité à confiner les électrons dans des points quantiques. Financé par le Conseil européen de la recherche, le projet CNT-QUBIT vise à mettre au point un système évolutif, entièrement électrique, capable d’établir par des mesures l’intrication quantique, un pré-requis essentiel de l’informatique quantique. CNT-QUBIT s’appuiera sur les interactions spin-orbite pour les rotations de spin et sur les interactions hyperfines pour le stockage d’informations quantiques. Les activités du projet consisteront notamment à coupler deux qubits de spin séparés dans l’espace à un seul résonateur électrique, ce qui induira une intrication s’ils ne peuvent être distingués par des mesures. Les informations quantiques contenues dans les qubits de spin électronique intriqués seront transférées aux spins nucléaires du carbone 13, qui devraient servir de mémoire quantique avec de longs temps de cohérence.
Objectif
The aim of this proposal is to use spin qubits defined in carbon nanotube quantum dots to demonstrate measurement-based entanglement in an all-electrical and scalable solid-state architecture. The project makes use of spin-orbit interaction to drive spin rotations in the carbon nanotube host system and hyperfine interaction to store quantum information in the nuclear spin states. The proposal builds on techniques developed by the principal investigator for fast and non-invasive read-out of the electron spin qubits using radio-frequency reflectometry and spin-to-charge conversion.
Any quantum computer requires entanglement. One route to achieve entanglement between electron spin qubits in quantum dots is to use the direct interaction of neighbouring qubits due to their electron wavefunction overlap. This approach, however, becomes rapidly impractical for any large scale quantum processor, as distant qubits can only be entangled through the use of qubits in between. Here I propose an alternative strategy which makes use of an intriguing quantum mechanical effect by which two spatially separated spin qubits coupled to a single electrical resonator become entangled if a measurement cannot tell them apart.
The quantum information encoded in the entangled electron spin qubits will be transferred to carbon-13 nuclear spins which are used as a quantum memory with coherence times that exceed seconds. Entanglement with further qubits then proceeds again via projective measurements of the electron spin qubits without risk of losing the existing entanglement. When entanglement of the electron spin qubits is heralded – which might take several attempts – the quantum information is transferred again to the nuclear spin states. This allows for the coupling of large numbers of physically separated qubits, building up so-called graph or cluster states in an all-electrical and scalable solid-state architecture.
Champ scientifique
- engineering and technologyelectrical engineering, electronic engineering, information engineeringinformation engineeringtelecommunicationsradio technologyradio frequency
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringcomputer hardwarequantum computers
- engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensors
Programme(s)
Régime de financement
ERC-COG - Consolidator GrantInstitution d’accueil
WC1E 6BT London
Royaume-Uni