Lieven Vandersypen

Title

Real and Futuristic Spin Qubits 

Abstract

Electrons confined in nanoscale semiconductor islands (quantum dots) occupy quantized orbitals, much like the  ectrons bound to an atomic nucleus. This opens prospects for the coherent control of their spin states, and may form the basis for a scalable quantum computer. We will show that all the necessary building blocks have now been realized in GaAs quantum dots, including initialization, single-shot read-out, coherent control of single spins, and coherent coupling of neighbouring spins. However, the localized electron spin interacts through the hyperfine coupling with about one million nuclear spins in the host material, which leads to a complex and unpredictable dynamics. We will review methods to nevertheless maintain control of the electron spins in this system, and also discuss novel material systems for quantum dots, in which nuclear spins can be avoided altogether.