Atom demo fixes quantum errors

R.A. Hettinga rah at
Fri Jan 7 11:36:09 PST 2005


Always On 

Atom demo fixes quantum errors


NewsTeam | TRN [] | POSTED: 01.07.05 @09:47

Although quantum computers promise fantastic speed for certain types of
very large problems, the logical components of quantum computers -- quantum
bits -- are quite fragile, which makes for a large number of errors that
must be corrected.

 Researchers from the National Institute of Standards and Technology have
demonstrated a way to correct errors in qubits of beryllium ions held in an
electromagnetic trap. The ions represent a 1 or 0 of computer information
in their spin, which can be pictured as the counterclockwise or clockwise
spin of a top.

 One way to carry out quantum computing is to take advantage of a weird
trait of quantum particles -- they can become entangled, or linked, so that
properties like spin remain in lockstep.

The researchers' prototype uses lasers to control the qubits' states and
electrodes to move them together, which allows them to be entangled. The
researchers set a primary qubit to a particular state and entangled it with
two other qubits. They deliberately induced an error and then disentangled
the qubits by separating them.

 They measured the other two qubits to determine how the primary qubit
needed to be corrected.

 Quantum error correction schemes have been well explored theoretically,
but the researchers' experiment was the first demonstration of a repeatable
error-correction procedure and the first using trapped ions, which are a
promising candidate for practical quantum computers.

 Practical quantum computing is a decade or more away. The method could be
used in quantum communications applications like quantum cryptography
within a few years, according to the researchers. The work appeared in the
December 2, 2004 issue of Nature.

R. A. Hettinga <mailto: rah at>
The Internet Bearer Underwriting Corporation <>
44 Farquhar Street, Boston, MA 02131 USA
"... however it may deserve respect for its usefulness and antiquity,
[predicting the end of the world] has not been found agreeable to
experience." -- Edward Gibbon, 'Decline and Fall of the Roman Empire'

More information about the cypherpunks-legacy mailing list