The idea remains controversial, but scientists reporting at the American Physical Society meeting in Dallas, US, are slowly unpicking how it could work.
The key, they say, is tiny packets of energy, or quanta, lost by electrons.
Experiments using tiny wires show that as electrons move on proteins within the nose, odor molecules could absorb these quanta and thereby be detected.
If the theory is right, by extending these studies, an "electronic nose" superior to any chemical sensor could be devised.
In 1996, Luca Turin, now of the Massachusetts Institute of Technology in the US, suggested that the "vibrational modes" of an odorant were its signature.
Molecules can be viewed as a collection of atoms on springs, and energy of just the right frequency — a quantum — can cause the spring to vibrate.
Since different assemblages of molecules have different characteristic frequencies, Turin proposed, these vibrations could act as a molecular signature.
The idea has been debated in the scientific literature, but presentations at the American Physical Society meeting put the theory on firmer footing.
Most recently, Dr Turin published a paper showing that flies can distinguish between molecules that are chemically similar but in which a heavier version of hydrogen had been substituted."
Link to Original Source