Two discrete energy levels in a quantum system, such as an atom, can be used to store a bit of information. However, quantum systems can also exist in superposition states, thereby storing both states of the bit simultaneously. This property can lead to an exponential increase in memory and processing capacity. It would enable a quantum computer to efficiently solve certain problems such as factorizing large numbers, which may be impractical on a classical computer. Actually building a useful quantum computer is an extremely daunting task due to the necessity of overcoming decoherence. Nevertheless, in the near term, the principles of quantum information processing are finding applications in metrology such as for atomic clocks and may also provide a way to efficiently simulate other quantum systems of interest. A quantum computer would also realize a mesoscopic version of "Schrödinger's Cat," a bizarre situation cooked up by Schrödinger in 1935 where a cat could be simultaneously dead and alive. A number of physical systems are currently considered for building a quantum computer; this talk will focus on the use of trapped atomic ions.

Argonne Physics Division Colloquium Schedule