ABSTRACT
Recent achievements in condensed matter science enable control of quantum
mechanical degrees of freedom in nano-structured solids. This eventually
may lead to devices with operation based on a single electron charge and/or
spin [1]. The major advantage of implementing the spin-based systems is
in a much weaker coupling of spin to the solid-state environment when
compared to charge [1]. In addition, localization of the electron spin in
nano-structures is known to dramatically prolong its quantum phase coher-
ence time when compared with structures with higher dimensionality [2-6].
Here an important example is given by semiconductor quantum dots (QD),
providing three-dimensional electron confinement and thus the full motional
quantization, which effectively decouples the electron spin from the orbital
motion [2-6]. This property in turn suppresses the spin decoherence rate
due to scattering processes (phonons, charge fluctuations) which couple to
the spin via the spin-orbit interaction. Thus quantum dot systems permit
accurate preparation on the nano-scale of quantum states with robust spin
properties.
