Quantum Leap Toward The Future

McGill University physicists have found a way to measure the energy needed to add electrons to semi-conductor nanocrystals (quantum dots). This new technology may well create a revolution in computing as well as in other scientific fields. McGill's Associate Dean of Research and Graduate Education for the Faculty of Science, Dr. Peter Grütter, says his team has created a cantilever force sensor that allows the removal of single electrons to be withdrawn and added to a quantum dot while the energy expended during the process is measured.

Getting Smaller

The ability to measure such small bits of energy is a huge step toward finding a way to replace the ubiquitous silicon chip contained in computers. This finding just about defines next generation computing. Today's computers use processors containing transistors in on or off positions, or conductors and semi-conductors. But quantum computing would enable a processor to work in more than one state. This would not only increase processing speed, but would also make the processors even smaller than they are now.

While most people think of quantum as meaning something huge, the word signifies the smallest amount by which some physical quantities can change. Learning more about these levels of energy helps researchers to comprehend and anticipate the electronic properties of nanoscale systems in development.

Replacing Chips

"We are determining optical and electronic transport properties," said Grütter. "This is essential for the development of components that might replace silicon chips in current computers."

The chemical properties of nanosystems are also determined by their electronic principles. That makes the team's research very important in helping to make these chemical processes more energy efficient and "green." One example of how this might work is to imagine the new technology as applied to lighting systems through the use of nanoparticles to improve energy efficiency. "We expect this method to have many important applications in fundamental as well as applied research," said McGill's Lynda Cockins from the university's Department of Physics.

Oscillation Amplitude

The explanation of how cantilever sensors work is not even that hard to understand,

"The cantilever is about 0.5 mm in size (about the thickness of a thumbnail) and is essentially a simple driven, damped harmonic oscillator, mathematically equivalent to a child's swing being pushed," explained Grütter. "The signal we measure is the damping of the cantilever, the equivalent to how hard I have to push the kid on the swing so that she maintains a constant height, or what I would call the 'oscillation amplitude.' "