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QUANTUM COMPUTING IS one of the most dynamic areas in
physics research today. Through the exploitation of quantum
superposition and entanglement, quantum processors are expected to outperform
conventional computers by many orders of magnitude in a wide variety of operations.
A number of primitive quantum operations have recently been demonstrated
using complex experimental arrangements, but these systems do not offer
a convenient path for mass-production.
A major advance occurred in 1998 when Dr. Bruce Kane of
UNSW's Semiconductor Nanofabrication Facility (SNF) proposed a solid-state quantum computer design based on a
precise array of phosphorous dopants embedded in a silicon host crystal
(Nature, 14 May, 1998). In this design,
quantum bits (or qubits) are stored on the spin of the phosphorous nuclei, so that
each dopant atom represents one qubit. The quibits are manipulated and
accessed using metallic gates on the surface of the chip together with external ac and
dc magnetic fields. The compatibility of this design with silicon
integrated circuit technology makes it a leading candidate for scale-up to many-quibit processor chips. Researchers at
SNF,
led by Professor Robert Clark, have since developed detailed
fabrication strategies for the realisation of
Kane's proposal, and have put in place substantial experimental
infrastructure to achieve this goal.
The UNSW program, together with Australia's prospects for involvement
in the commercialisation of this new technology, received a major boost
in October 1999 when the Australian Research Council announced that
it would fund a Centre for Quantum Computer Technology for an
initial three-year cycle 20002002 (see Physics World, January, 2000). ARC Special Research Centres can
continue for up to nine years following review at years three and six.
Professor Clark is Director of the new Centre, which brings together over
sixty research staff and students from UNSW, the University of Queensland and
the University of Melbourne. The UNSW node will focus on the fabrication of
test devices using recently established facilities for atomic-scale
lithography and MBE crystal growth, together with its well-established
nanofabrication capabilities at the Semiconductor Nanofabrication Facility. |
The
SNF comprises a three-storey, 400m2 complex of environmentally
controlled class 3.5 and 350 clean-rooms and is coordinated jointly at UNSW by
the Faculty of Science and Technology and the Faculty of Engineering. The
UNSW node will also lead the effort in electrical quantum state
read-out, utilising its experience in low-temperature quantum measurement
and sophisticated cryomagnetic equipment at the National Magnet Laboratory.
The University of Queensland node is led by the Centre's Deputy
Director, Professor Gerard Milburn, a world-renowned expert in the theory
of quantum computation. This node will also investigate optical quantum
state read-out. Associate Professor Steven
Prawer heads the University of Melbourne node, which will focus
on phosphorous ion implantation techniques and semiconductor
surface analysis.
A formal collaboration on this project has also been established by
UNSW with Los Alamos National Laboratory (LANL) in the USA, a centre
of excellence in theoretical quantum computation and materials research. This linkage involves an extensive exchange of research staff and
students between UNSW and LANL each year.
The Centre for Quantum Computer Technology held a highly
successful inaugural three-day Research Workshop at Mt. Victoria, near Sydney,
in December 1999, attended by 28 staff and 14 graduate students from the
three nodes. The Centre is currently expanding and will support a number
of new postdoctoral appointments at the three University nodes beginning
in 2000, together with increased funding for PhD scholarships, providing
exciting opportunities for graduate students, including research visits to
collaborating Australian and US laboratories.
Robert
Clark, Andrew Dzurak,
Alex Hamilton, Nancy Lumpkin
& Michelle Simmons
Centre for Quantum Computer Technology |
