But Dr Turin believes that the way smell molecules wiggle and vibrate is responsible - thanks to the quantum effect called tunnelling.

BBC: Perfume chemist

From that, through a complicated and rather tiresome procedure involving phenomena known as the Josephson effect and the quantum Hall effect, it is possible to express electrical power in terms of h and so, to calculate h in terms of the balanced mass.

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Whether quantum-effect transistors or something else altogether will hold even more surprises, it is too early to tell.

ECONOMIST: The transistor��s heir

Nonetheless, among the greatest sceptics of quantum-effect devices are some of their inventors.

ECONOMIST: The transistor��s heir

One of these is that if it is placed in a magnetic field it exhibits a phenomenon known as the relativistic quantum Hall effect.

ECONOMIST: The 2010 Nobel prizes

But then there is another difficulty: making the components exactly the right size is even more crucial for a quantum-effect device than for a regular transistor.

ECONOMIST: The transistor��s heir

However, quantum-effect devices have some severe flaws of their own.

ECONOMIST: The transistor��s heir

Second, quantum-effect devices are sensitive to minuscule control currents.

ECONOMIST: The transistor��s heir

Such quantum-effect devices were first devised in the 1980s.

ECONOMIST: The transistor��s heir

The Sommerfeld effect, a quantum-mechanical process that makes particles more likely to interact with one another in some circumstances and less likely in others, is mostly ignored in particle physics because it applies only in a limited range of conditions.

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It is now possible to compute the quantum-mechanical properties of atomic systems that are in effect infinite.

ECONOMIST: MONITOR