Quantum
Logic Experiments with Trapped Barium Ions
The field of Quantum
Computation has arisen in the last few years from an idea of Richard Feynman
that quantum mechanics might lead to a qualitatively new kind of computer
that is far more powerful than any classical device. In the Ion Trap project
scientists are testing the principles of quantum logic using individual
trapped ions, which are suspended in ultra-high vacuum by electromagnetic
forces. This isolates the ions from the environment so that the
superposition states required for quantum computation can live for a
relatively long time.
Each ion contains a
single quantum bit (qubit) of information and the ions can communicate with
each other via trap phonons (modes of vibration of the trapped ions). Lasers
are used to cool the ions to microKelvin temperatures and to read and write
information into and out of each ion. The picture shows a pair of barium
ions which have been brought to rest by laser cooling at a separation of 1.5
microns. Current experiments are directed at understanding what processes
limit the superposition state lifetime (decoherence), which is the most
important limiting factor in quantum computation.
Image
of two ions in a trap
Additional
Information
