"Writing, reading and controlling the state of single spins in semiconductors using a single, optical pulse"

Speaker:Professor David Gershoni
Affiliation:Dept. of Physics and Solid State Institute, Technion
Abstract:The ability to coherently control spins in matter is essential for realizations of future technologies which rely on quantum information processing. In general, quantum information processing requires ability to write, read and control isolated physical two level system (qubits) states with high fidelity, much faster than the system's life- and coherence-times.
We demonstrate these abilities, for the first time, by applying sequences of three resonant picosecond laser pulses to single semiconductor quantum dots, where the matter-qubit is formed by the two-spin-states of a single, quantum-confined, optically excited electron.
The first pulse transfers the pulse polarization to the polarization of the spin.
The second pulse rotates the spin direction around any desired direction in space by any desired angle (a universal gate operation). The third pulse 'reads' the new spin state by measuring the spin's projection.