Colloquium on February 18th, 2008

Charles Marcus
Harvard University

Schrödinger's Chip: Semiconductor Approaches to Quantum Information

We all know the story of Schrödinger’s cat, half-alive, half-dead,
existing in its sealed box in this dual state, awaiting a glance from
outside to determine its fate. The story not only illustrates the
counterintuitive role of measurement in quantum mechanics, but also how
the preservation of quantum properties, which dominate at atomic scales
(even at room temperature), become less familiar and even absurd for
large multi-particle objects. Building computer chips that can take
advantage of quantum coherence and entanglement to allow improvements in
computation and simulation is much like building the sealed box for the
cat. The challenge is to permit large many-particle systems to selective
interact with the outside world without too quickly destroying the
quantum coherence that makes them work. The operating regime can be
termed nano-milli-giga: nanometers, millikelvin, and gigahertz. This
talk provides an overview of various efforts worldwide to design and
build quantum information processing systems on semiconductor chips.