A research team at the National Research Council Canada (Ottawa) has developed a new quantum technology which uses laser pulses to control quantum processes. The method, which is described in the October 13th web release by the world's leading scientific journal, Science, was illustrated by changing the outcome a chemical reaction.
Quantum technologies make use of the molecular scale properties of matter. At this scale, which is different from our everyday world, matter behaves according to the rules of quantum mechanics. Although the rules are well understood, the tools required to control quantum processes are still under development. Quantum technologies aim to manipulate molecular scale behaviour, in a way not usually seen in nature, for fundamentally new applications. For example, methods to implement quantum information/computation (i.e. computers based upon quantum rules) are the subject of an international race to harness the power of this new technology. Another example of quantum technology is the control of chemical reactions using laser light, the example chosen by the NRC researchers to illustrate their new approach.
A chemical reaction, in which a starting molecule is converted to a product, follows path that seems to a molecule like a hill it must 'ski' down, as shown in the figure. Here a molecule would normally react by heading down the hill towards valley B. The NRC team describes an experiment that is analogous to the 'Labyrinth' game in which a player controls the tilt of a board in order to guide a steel ball through a maze of holes; in this case a molecular scale game. The knob the researchers used is an ultrafast laser pulse (shown here as a wiggly black arrow) which re-shapes the hill (or tilts the board) as the molecule is sliding down the slope, using an interaction called the Dynamic Stark Effect. In this molecular 'Labyrinth' game, the interaction deflects the reacting molecule towards valley A rather th
Contact: Dr. Albert Stolow
National Research Council of Canada