The long term aim of this work is to study the suitability of using laser
cooled Ca+ ions in Penning traps as the basic components of a quantum
computer. A great deal of progress in the field of quantum computing has
been made in recent years with laser cooled ions stored in radio frequency
ion traps. Building a useful quantum computer with trapped ions is however
extremely challenging. Penning traps offer some possible benefits over radio
frequency traps. They also create some additional difficulties. The potential
advantages and disadvantages of Penning traps are discussed throughout the
thesis.
We show that we are able to overcome the problems associated with laser
cooling in Penning traps, and have trapped single ions for extended periods of
time. Pairs of Ca+ ions have been aligned along the axis of a Penning trap,
and have been optically resolved.
A novel Penning trap array based on PCB boards has been developed. A
prototype was built and tested, along with the electronics required to shuttle
ions between different sub-traps. Ions have been shuttled a distance of 10 mm
in 2.5 μs. A return trip efficiency of up to 75% was seen.
A quantum effect – J-state mixing caused by large magnetic fields – has
been observed for the first time in single atomic ions. The magnetic field
causes a forbidden [Delta]J = 2 transition to become weakly allowed. This effect
is of general interest in atomic physics, and is also very relevant for quantum
computation studies. A quantitative prediction of the magnitude of the
J-mixing effect has been derived theoretically. This is compared to experimental
data, and is found to be in excellent qualitative and good quantitative
agreement.