ABSTRACT
The spin of electrons in quantum dot systems can bemanipulated by
means of time dependent ac electric and magnetic fields. Among the
different realizations, two ground-breaking experiments in double
quantum dots (DQDs) must be mentioned: quantum spin SWAP
operations have been realized by sharp voltage pulses coupled
to exchange interaction [Petta et al. (2005)]; single electron spin rotations have been controlled by oscillating magnetic fields in
electron spin resonance like experiments [Koppens et al. (2006)]. Both operations are of fundamental relevance in the aim of building
spin based qubits in quantum dot systems [Loss and DiVincenzo
(1998)]. Most of these experiments make use of two particle
phenomena such as Coulomb interactions and Pauli exclusion
principle. The first one leads to Coulomb blockade which allows to
tune the system to configurations when only a few electrons are
actively involved in the dynamics [Kouwenhoven et al. (2001)]; the
latest one brings to spin blockade (SB) of the current when electrons
with parallel spin try to occupy the same orbital [Ono et al. (2002)]. In this chapter, we will focus on the effect of ac magnetic fields as
they act directly on the spin degree of freedom. Aswewill see, orbital
effects such as Aharonov-Bohm (AB) phases will also play a role.
