Letter abstract
Nature Nanotechnology 2, 39 - 42 (2007)
Published online: 3 January 2007 | doi:10.1038/nnano.2006.174
Subject Categories: Nanomagnetism and spintronics | Quantum information
Rare-earth solid-state qubits
S. Bertaina1,2, S. Gambarelli3, A. Tkachuk4, I. N. Kurkin5, B. Malkin5, A. Stepanov6 & B. Barbara1
Abstract
Quantum bits (qubits) are the basic building blocks of any quantum computer. Superconducting qubits have been created with a top-down approach that integrates superconducting devices into macroscopic electrical circuits1, 2, 3, and electron-spin qubits have been demonstrated in quantum dots4, 5, 6. The phase coherence time (
2) and the single qubit figure of merit (QM) of superconducting and electron-spin qubits are similar — at 2 
s and QM 10–1,000 below 100 mK — and it should be possible to scale up these systems, which is essential for the development of any useful quantum computer. Bottom-up approaches based on dilute ensembles of spins have achieved much larger values of 2 (up to tens of milliseconds; refs 7,8), but these systems cannot be scaled up, although some proposals for qubits based on two-dimensional nanostructures should be scalable9, 10, 11. Here we report that a new family of spin qubits based on rare-earth ions demonstrates values of 2 (50 s) and QM (1,400) at 2.5 K, which suggests that rare-earth qubits may, in principle, be suitable for scalable quantum information processing at 4He temperatures.
- Institut Néel, Département Nanosciences, CNRS, 25 Ave. des Martyrs, BP166, 38042 Grenoble Cedex 9, France
- Ecole Nationale Supérieure de Physique, INP de Grenoble, Minatec 3 parvis Louis Néel, BP 257, 38016 Grenoble Cedex 9, France
- Laboratoire de Chimie Inorganique et Biologie (UMR-E 3 CEA-UJF), DRFMC, CEA-Grenoble, 17 rue des Martyrs 38054 Grenoble Cedex 9, France
- S.I. Vavilov State Optical Institute, St Petersburg 199034, Russian Federation
- Kazan State University, Kazan 420008, Russian Federation
- Laboratoire de Matériaux et Microélectronique de Provence, Faculté St Jérôme, C142, 13397, Marseille Cedex 20, France
Correspondence to: B. Barbara1 e-mail: bernard.barbara@grenoble.cnrs.fr
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