Diamond Materials

Diamond Materials for Quantum Application

23. September 2014: The DFG research group FOR 1493 “Diamond Materials and Quantum Applications” goes into its second funding period. FOR1493 is a national research consortium funded by the Deutsche Forsch-ungsgemeinschaft.

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ERC Advanced Grant


Reading out spin states of single nuclei

Being able to read out the state of a quantum mechanical object without subsequent destruction of that state is at the heart of numerous quantum feed forward protocols like error correction, entanglement purification. In general a dedicated setting of the measurement device is needed in order to couple strong enough for the readout process to yield a sufficient signal for state identification and yet to preserve the state measured. For the nitrogen-vacancy spin defect in diamond such a setting is achieved for the nitrogen nucleus with an appropriately chosen magnetic field strength and orientation (see Neumann et al. Science 329 (2010) 542ff.). Single shot and quantum non demolition readout of electron spins in this system has not been conclusively demonstrated owing to fast repolarization of the electron spin due to laser excitation and fluorescence readout of the center. However the nitrogen nuclear spin with its hyperfine coupling tensor aligned with the symmetry axis of the electron spin wavefunction is sufficiently decoupled from the electron spin dynamics provided a magnetic field of sufficient strength and orientation along the C 3v center axis is chosen. The work presents a major step towards application of diamond spin defects in quantum science. It might facilitate scaling of spin arrays in the system and even lead to more sensitive parameter estimation in electric and magnetic field measurements.

Original publication:
Title: Single-Shot Readout of a Single Nuclear Spin
Author(s): Neumann,P.,Beck, J., Steiner, M., Rempp, F., Fedder, H., Hemmer, P.R., Wrachtrup, J., Jelezko, F.
Source: Science
Volume: 329
Issue: 5991
Pages: 542 – 544
Published: 30 July 2010