Generation of three-qubit entangled states using superconducting phase qubits

Neeley, M. et al. (2010) Generation of three-qubit entangled states using superconducting phase qubits. Nature, 467(7315), pp. 570-573. (doi: 10.1038/nature09418) (PMID:20882012)

Abstract

Entanglement is one of the key resources required for quantum computation1, so the experimental creation and measurement of entangled states is of crucial importance for various physical implementations of quantum computers2. In superconducting devices3, two-qubit entangled states have been demonstrated and used to show violations of Bell’s inequality4 and to implement simple quantum algorithms5. Unlike the two-qubit case, where all maximally entangled two-qubit states are equivalent up to local changes of basis, three qubits can be entangled in two fundamentally different ways6. These are typified by the states |GHZ〉 = (|000〉 + |111〉)/ and |W〉 = (|001〉 + |010〉 + |100〉)/. Here we demonstrate the operation of three coupled superconducting phase qubits7 and use them to create and measure |GHZ〉 and |W〉 states. The states are fully characterized using quantum state tomography8 and are shown to satisfy entanglement witnesses9, confirming that they are indeed examples of three-qubit entanglement and are not separable into mixtures of two-qubit entanglement.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Weides, Professor Martin
• Authors: Neeley, M., Bialczak, R. C., Lenander, M., Lucero, E., Mariantoni, M., O’Connell, A. D., Sank, D., Wang, H., Weides, M., Wenner, J., Yin, Y., Yamamoto, T., Cleland, A. N., and Martinis, J. M.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Nature
• Publisher: Nature Publishing Group
• ISSN: 0028-0836
• ISSN (Online): 1476-4687
• Published Online: 29 September 2010