Gershoni, David

Friday September 30, 2011
Time: 11:00
Place: HPF G 6
Host: Atac Imamoglu

Writing, reading and controlling the spin of single matter spin qubits using a single picosecond laser pulse

David Gershoni
Institute of Technology, Haifa, Israel

The ability to coherently control matter qubits is essential for realizations of quantum information processing (QIP). In general, QIP requires ability to write, read and control the qubit state. It goes without saying that these operations should be performed with high fidelity, much faster than the qubit's life- and decoherence-times.

We demonstrate reading, writing and complete control over the spin of a single correlated electron-hole pair (exciton) confined in a single QD. Each one of these operations is performed using a single, picoseconds long, polarized optical pulse tuned to a specific excitonic or biexcitonic resonance. Our approach requires no external magnetic field and it does not depend on the coherent evolution of the excitonic spin.

In particular, we demonstrate three degrees of freedom in rotating the exciton spin.  This allows, for the first time, implementation of a universal gate using one optical pulse, only.

Parts of my talk can be found in:

[1] E. Poem et al," Accessing the dark exciton with light "Nature Physics 6, 993-997, (2010)
[2] Y. Benny, et al., Phys. Rev. Lett. 106, 040504, (2011)
[3] Y. Benny, et al "Two-photon- photoluminescence excitation spectroscopy of single quantum-dots" Phys. Rev. B. 84, 075473, (2011).
[4] E. Poem, et al "Optically induced rotation of a quantum dot exciton spin." Phys. Rev. Lett. 107, 087401, (2011).