Demonstration of entanglement-by-measurement of solid-state qubits
Abstract
Projective measurements are a powerful tool for manipulating quantum states. In particular, a set of qubits can be entangled by measuring a joint property such as qubit parity. These joint measurements do not require a direct interaction between qubits and therefore provide a unique resource for quantum information processing with well-isolated qubits. Numerous schemes for entanglement-by-measurement of solid-state qubits have been proposed, but the demanding experimental requirements have so far hindered implementations. Here we realize a two-qubit parity measurement on nuclear spins localized near a nitrogen-vacancy centre in diamond by exploiting an electron spin as a readout ancilla. The measurement enables us to project the initially uncorrelated nuclear spins into maximally entangled states. By combining this entanglement with single-shot readout we demonstrate the first violation of Bell's inequality with solid-state spins. These results introduce a new class of experiments in which projective measurements create, protect and manipulate entanglement between solid-state qubits.
- Publication:
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Nature Physics
- Pub Date:
- January 2013
- DOI:
- 10.1038/nphys2444
- arXiv:
- arXiv:1206.2031
- Bibcode:
- 2013NatPh...9...29P
- Keywords:
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- Quantum Physics;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- 6 pages, 4 figures