EVENTS, ADVANCES, AND NEWS
■ BY JEFF ECKERT
OBSERVED IN LAB
PHOTO CREDI T: D. CASSIDY, UCR.
abstract, but the implications are fairly
profound. Apparently, the creation of coherent gamma radiation could aid in the
advancement of fusion power and, more
dramatically, allow the creation of such
weapons as gamma-ray lasers. The latter
compared to today’s lasers would be
something like nuclear bombs compared
to dynamite. The research was funded
by the National Science Foundation, but
the military is no doubt paying attention.
■ The ultra-high vacuum target chamber,
where the intense positron pulse is
implanted into porous silica film.
ILLUSTRATION B Y MICHAEL KEMPER, COURTESY OF NIS T.
In case you’re not up on particle
physics, note that when an electron
meets its antimatter counterpart — the
positron — this generally results in
mutual annihilation and the release of
a couple gamma rays. But occasionally, a hydrogen-like atom — with the
proton replaced by the positron — may
be formed and exist for something like
0.1 ns in the form of positronium (Ps).
Physicists tell us that about 15
billion tons of positrons are annihilated
every second in the Milky Way bulge,
so there must be quite a bit of it
around. However, until recently, no
one had created it in a lab. Enter Prof.
Allen Mills and researcher David
Cassidy, of the University of California,
www.ucr.edu), who have
done exactly that by firing intense
bursts of positrons into a thin film of
porous silica, which catches them like
a cage, slows down the process, and
makes the Ps atom temporarily stable.
According to Cassidy, “This is the
first step in our experiments. What we
hope to achieve next is to get many
more of the positronium atoms to
interact simultaneously with one
another — not just two positronium
atoms at a time.”
The concept may seem hopelessly
10 December 2007
didates, such as individual atoms.
Unlike the standard data bit, which
holds only a 0 or 1 value, a quantum bit
(qubit) can hold opposite values at the
same time (superposition), much like a
really tiny politician. This offers the possibility of exponentially faster computations. The resonant section of the NIST
cable, known as a quantum bus, shuttles
information between two or more qubits.
In the recent experiment, the
scientists fabricated two qubits on a sapphire microchip and plunked them into
an 8 cu. mm shielded box. The quantum bus was 7 mm long and zig-zagged
round the 1.1 mm space between the
qubits. Using the cable’s ability to
resonate at a particular frequency, the
experimenters encoded information in
one qubit, transferred it as microwave
energy to the quantum bus for 10 ns,
then transferred it to a second qubit. As
an added benefit, the cable might also
be used to transfer quantum information between matter and light.
EN TERS FINAL TESTING
■ Artist’s rendition of the NIST superconducting quantum computing cable.
Quantum computers may be many
years away, but someone has
already figured out a way to connect
their innards. Physicists at the National
Institute of Standards and Technology
reported the successful transfer of
information between two “artificial
atoms” using electronic vibrations on
microfabricated aluminum cable. It’s
sort of like CATV, only with no
electrical resistance, plus multitasking
data bits that operate under the rules
of quantum physics. An advantage is
that this type of connector may be
easier to manufacture and scale up
to a practical size than competing can-
PHOTO COUR TES Y OF ADVANCED TRANSPORT SYS TEMS LTD.
■ The ULTra transportation system at
the Cardiff trials site.
On a more practical level, the first
full production version of the
Urban Light Transport (ULTra) Personal
Rapid Transit (PRT), from Advanced
Transport Systems Ltd. (ATS, www.
atsltd.co.uk), has been delivered to the
Cardiff (Wales) trials site for commis-