Quantum control and decoherence of spins in solids

 This research aims at controlling the quantum states of single and coupled spins in diamond, and to study and counteract decoherence. NV centers are excellent test beds for these studies, as spin coherence times are long and quantum states can be created with high fidelity. Moreover, the spin environment of NV centers can be tuned in situ, allowing strategies to maintain coherence to be tested in different environments. This work is motivated by a fundamental interest into the process of decoherence as well as by potential applications of solid state spins in quantum information processing.

Collaboration with Slava Dobrovitski (Ames Lab), David Awschalom (UCSB) and Daniel Lidar (USC)

Recent achievements:

Controlling the quantum dynamics of a mesoscopic spin bath in diamond

We have achieved quantum control of a mesoscopic electron spin bath surrounding a single electron spin in diamond at room temperature. The resulting spin bath dynamics are probed using a single NV centre electron spin as a magnetic field sensor.

G. de Lange, T. van der Sar, M.S. Blok, Z.H. Wang, V.V. Dobrovitski, R. Hanson, Scientific Reports 2, 383 (2012)

Going even further, we can experimentally isolate, characterize, and coherently control up to six individual nuclear spins that are weakly coupled to the NV center electron spin. This is achieved by using pulse sequences on the electron spin that amplify the interaction with a selected nuclear spin while at the same time suppress decoherence caused by the rest of the spin bath.

T. H. Taminiau, J. J. T. Wagenaar, T. van der Sar, F. Jelezko, V. V. Dobrovitski, R. Hanson, Phys. Rev. Lett. 109, 137602 (2012)


Single-spin magnetometry with multi-pulse sequences

Using multi-pulse sensing sequences the ac magnetic-field sensitivity of a single-spin magnetometer is increased significantly. In addition, we measured the full frequency-filtering characteristics of different multi-pulse schemes.

G. de Lange, D. Ristè, V.V. Dobrovitski, R. Hanson, Phys. Rev. Lett. 106, 080802 (2011).

 

Universal dynamical decoupling of a single solid-state spin from a spin bath

We have dramatically suppressed the coupling of a single spin in diamond with the surrounding spin bath using dynamical decoupling. The coherence time increased by more than 25 times. The decoupling works for arbitrary quantum states, as is verified by quantum process tomography.

G. de Lange, Z. H. Wang, D. Ristè, V. V. Dobrovitski, R. Hanson, Science 330, 60 (2010).

Earlier publications:

V.V. Dobrovitski, G. de Lange, D. Ristè, R. Hanson, Phys. Rev. Lett. 105, 077601 (2010).

Contact

For questions, inquiries and applications please contact Ronald Hanson.