Computers based on the powerful properties of quantum mechanics
have the potential to revolutionize information technology and
security, but for decades they have remained more theoretical
than practical, and difficult to scale up. That is changing,
however, as demonstrated in a report this week in the journal
Science. In the paper, engineers and physicists from Stanford
and the University of California at Santa Barbara demonstrate a
potential progenitor of an essential component of quantum
computers, "a logic gate" that enables interaction between just
two particles of light. The key advance is a solid state device
that can reliably produce an interaction between the light
particles, called photons. The team, led by Stanford Electrical
Engineering Assistant Professor Jelena Vuckovic, did that by
nestling a tiny ball of indium arsenide molecules called a
"quantum dot" within a cavity on a photonic crystal, a chip of
semiconducting gallium arsenide precisely drilled with holes to
give it the ability to trap ph