The word “quantum” derives from the Latin word for “amount,” so that if something is “quantifiable,” it means that it can be measured. Although I think I have a reasonably good grasp of chemistry, I’ll admit that my knowledge of “quantum chemistry” is quantifiably very small. But it is enough to allow me to appreciate the magnitude of this year’s Nobel Prize in chemistry, awarded to Drs. Moungi Bawendi of MIT, Louis Brus of Columbia University and Alexei Ekimov of Nanocrystals Technology Inc. in New York for the discovery and development of “quantum dots.” Ah, there is that troublesome word, “quantum.”
A “quantum” is usually defined as the smallest discreet unit of something that can be measured. For example, a quantum of electricity is the electron, a quantum of light is the photon. However, in chemistry, the term is used to describe particles that are so small that their properties are very different from that exhibited on a larger scale. On the quantum scale, we are talking about particles measured in nanometers, that is, billionths of a meter. On this scale, gold instead of its usual yellow colour becomes ruby red. “Quantum dots” can be thought of as being tiny flecks of a substance that behave differently from larger pieces of the same substance. In this case, size really does matter!
In the Middle Ages there were arguments about the number of angels that can stand on the head of a pin. We will leave that argument aside, but we can quantify the quantum dots that would cover the head of a pin. About half a million! And these quantum dots have some amazing properties! They can absorb light of one colour and emit a different colour, with that colour depending on the size of the particle. This year’s Nobel Laureates were recognized for explaining this phenomenon and for developing a technique to produce quantum dots.
Lest you think that this is only of academic interest, it is not. If you have marveled at the accurate, bright colours of a QLCD television screen, you should know that the “Q” stands for quantum dot. They’re also used in computer screens, lasers and solar panels. Quantum computing uses silicon quantum dots that have superior electronic properties to their larger counterparts and perform calculations at fantastic speeds. Quantum dots can also cross the blood brain barrier and deliver drugs to the brain!
There is yet another bonus that comes with awarding of the Nobel for quantum dots, one that science communicators will appreciate. The public will see the word “quantum” used in its proper sense and hopefully bring to light its frequent misuse. Health guru Deepak Chopra speaks of “quantum healing.” I would think you would want macro healing, not quantum healing. Another bit of Chopra wisdom: “Viewing your body from the perspective of quantum physics opens up new modes of understanding and experience the body and its aging. The practical essence of this new understanding is that human beings can reverse their aging.” That’s a quantum leap of nonsense. Ah, another misuse of the word. This isn’t a quantum leap, it is a giant leap of nonsense! The James Bond Movie “Quantum of Solace” makes a bit more sense since it refers to the small amount of solace that comes from taking revenge for the killing of a loved one. And now for a final correct use of the term. The work of this year’s chemistry Nobel Prize winners for the development of quantum dots will have far more than a quantum impact.