(May 24, 2012) While several building blocks for a quantum computer have already been successfully tested in the laboratory, a network requires one additonal component: a reliable interface between computers and information channels. In the current issue of the journal Nature, physicists at the University of Innsbruck report the construction of an efficient and tunable interface for quantum networks.
Quantum
technologies promise to redefine the landscape of information processing and
communication. We already live in an information age, in which vast amounts of
data are sent around the world over optical fibers, but future quantum networks
may be many times more powerful. These networks will require interfaces that
can transfer information from quantum processors onto light particles
(photons). Such interfaces will allow optical fibers to transmit
information-bearing photons between remote data registers, which are likely to
be composed of quantum dots or ions. In contrast to classical information,
quantum information can’t be copied without being corrupted. Instead,
physicists around the world are searching for ways to transfer quantum
information between matter and light using entanglement, the quantum property
in which the state of one particle depends on the state of a second. Now, a
research team led by Rainer Blatt, Tracy Northup, and Andreas Stute at the
University of Innsbruck’s Institute for Experimental Physics has demonstrated
the first interface between a single ion and a single photon that is both
efficient and freely tunable.