Project description DEENESFRITPL Carbon nanotubes offer a pathway to testing quantum entanglement at scale Carbon nanotubes provide an excellent host for spin qubits owing to their unique electronic properties and the ability to confine electrons in quantum dots. Funded by the European Research Council, the CNT-QUBIT project aims to develop a scalable, entirely electrical system that can establish quantum entanglement, a key requirement for quantum computing, through measurements. CNT-QUBIT will utilise spin-orbit interactions for spin rotations and hyperfine interactions for quantum information storage. Project activities will involve coupling two spatially separated spin qubits to a single electrical resonator, resulting in entanglement if they are indistinguishable by measurements. Quantum information in the entangled electron spin qubits will be transferred to carbon-13 nuclear spins, which should serve as a quantum memory with long coherence times. Show the project objective Hide the project objective Objective 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. Fields of science engineering and technologyelectrical engineering, electronic engineering, information engineeringinformation engineeringtelecommunicationsradio technologyradio frequencyengineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringcomputer hardwarequantum computersengineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensors Programme(s) H2020-EU.1.1. - EXCELLENT SCIENCE - European Research Council (ERC) Main Programme Topic(s) ERC-CoG-2014 - ERC Consolidator Grant Call for proposal ERC-2014-CoG See other projects for this call Funding Scheme ERC-COG - Consolidator Grant Host institution UNIVERSITY COLLEGE LONDON Net EU contribution € 1 998 574,00 Address GOWER STREET WC1E 6BT London United Kingdom See on map Region London Inner London — West Camden and City of London Activity type Higher or Secondary Education Establishments Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 998 574,00 Beneficiaries (1) Sort alphabetically Sort by Net EU contribution Expand all Collapse all UNIVERSITY COLLEGE LONDON United Kingdom Net EU contribution € 1 998 574,00 Address GOWER STREET WC1E 6BT London See on map Region London Inner London — West Camden and City of London Activity type Higher or Secondary Education Establishments Links Contact the organisation Opens in new window Website Opens in new window Participation in EU R&I programmes Opens in new window HORIZON collaboration network Opens in new window Total cost € 1 998 574,00
