Scientists have made yet another advancement
in the area of quantum computers. An international team composed of members
from the London Center for Nanotechnology, U.S. Department of Energy's
Brookhaven National Laboratory, Johns Hopkins University, among others,
reported that they detected a hidden magnetic “quantum order” or “string order”
that extends over chains of 100 atoms, or a length of 30 nanometers, in a
ceramic without classical magnetism.
These findings, published last week in the journal Science, could help lead to the
development of quantum computers and other materials at the nanoscale.
“Quantum mechanics is normally appreciated only on the
atomic scale. However, here we present evidence for a very long and very
quantum mechanical magnetic molecule,” said Collin Broholm, professor in the
Henry A. Rowland Department of Physics and Astronomy at Johns Hopkins' Krieger
School of Arts and Sciences. “While disordered to a classical observer, the
magnetic moments of almost 100 nickel atoms arranged in a row within a solid
were shown to display an underlying quantum coherence limited only by chemical
and thermal impurities. The progress we made is really a demonstration of
quantum coherence among a larger number of atoms in a magnet than ever before.”
The spin of an individual electron is an excellent qubit,
but in a real material it interacts with other electrons, disturbing its quantum
properties. The new research is important because it explicitly demonstrates,
using a practical material, that a large number of electron spins can be
coupled together to yield a quantum mechanical state with no classical analog.
In addition, the team has also established the factors that affect the distance
over which the hidden 'quantum order' can be maintained.
“Our goal is to understand the factors that affect the
distance over which the hidden 'string order,' or quantum phase coherence, can
be maintained,” says Brookhaven Lab physicist Guangyong Xu. “If you are
manufacturing something, you don't want a certain property to be maintained
only at one spot. You want the property maintained throughout the material.”
Quantum computing uses the concept of a “qubit,” which
differs from the traditional computer bit in that it does not rely on the
binary states of 1 or 0, or on or off. The qubit architecture lead some to
believe that quantum computing may be far more effective at solving certain
problems that still challenge even the world’s fastest computers today.