V.V. Dobrovitski
Ames Lab and Iowa State University
Harnessing quantum properties of electron and nuclear spins for new applications is an exciting research endeavor, holding much promise for high-precision metrology, coherent spintronics, and quantum information processing. However, progress in these areas is limited, because the desirable quantum properties (quantum coherences) are easily destroyed in real systems due to interaction of the quantum spins with the outside world. This decoherence phenomenon, being of fundamental importance for any real physical system, is under active investigation now. Recent experimental advances made possible to monitor and manipulate the real-time dynamics of single quantum spins in solid state environments, thus making the decoherence studies directly relevant for experiments. I will present our recent theoretical research on quantum spin dynamics and decoherence in some experimentally interesting systems and environments, such as spins of electrons and nuclei of impurity centers in diamonds [1], and electron spins in quantum dots [2]. We will discuss advanced numerical approaches to decoherence modeling, which can be used for accurate simulations of the environments comprising tens to thousands of quantum spins. By using these tools, we can approach some interesting decoherence regimes, as well as investigate various quantum control protocols designed for suppressing decoherence in spin systems. We will show how specially designed protocols can increase the coherence time by orders of magnitude, and in some cases, even completely freeze decoherence [3].
[1] R. Hanson, V. V. Dobrovitski, A. E. Feiguin, O. Gywat, and D. D. Awschalom, Science 320, 5874 (2008).
[2] K. A. Al-Hassanieh, V. V. Dobrovitski, E. Dagotto, and B. N. Harmon, Phys. Rev. Lett. 97, 037204 (2006).
[3] W. Zhang, V. V. Dobrovitski, L. F. Santos, L. Viola, and B. N. Harmon, Phys. Rev. B 75, 201302 (2007).
Friday, October 17th at 4:00 PM
Room L211, Technological Institute
Refreshments are served at 3:30 PM
