Quantum physics, from theory to ongoing revolution
In the early 1900s observations were made that were not consistent
with traditional, classical physics. For example, researchers concluded
that hot, black bodies emitted electromagnetic radiation at wavelengths
that were not expected, and that atoms could only emit and absorb light
of specific frequencies.
In 1900 the physicist Max Planck suggested that light was emitted
in small, discrete “packages” – that it was quantised – in order to
explain these discrepancies. This marked the start of quantum physics,
which describes the world at the atomic level. The brightest physicists
of the time, including Niels Bohr and Albert Einstein, led further
development. They soon realised that they were on the trail of a
paradigm shift, rather than just an adjustment to classical physics. In
the 1930s, quantum theory was essentially complete, even though many of
its consequences were only understood much later.
Quantum physics has had an enormous impact on society. By
exploiting the characteristics of quantum physics in light and materials
researchers invented both the laser and the transistor. Such inventions
form the basis of information technology as a whole – computers, the
internet and much more besides – which to a large extent shape today’s
society. This was the first quantum revolution.
But even though researchers learnt how to exploit certain quantum
characteristics, it was long regarded as impossible to control
individual quantum systems such as individual atoms, electrons or light
particles (photons). It was only in the 1980s that researchers succeeded
in developing methods for measuring and controlling individual atoms
and photons, work resulting in the award of the 2012 Nobel Prize in
Physics. In parallel with this, other researchers developed electronic
components from semi-conductors and superconductors, in which they could
manipulate individual electrons.
The control of individual quantum systems has opened the door to a
second quantum revolution, offering entirely new possibilities. Today
there are goals such as extremely rapid computers, intercept-proof
communications and hyper-sensitive measuring methods.
After many years of fundamental research the applications are
coming within reach, and researchers as well as policy-makers and
business managers are starting to realise that quantum technology has
the potential to change our society significantly. Significant
investment is now going into quantum technology throughout the world.
The EU is launching a decade-long billion-euro investment programme in
2019. There are programmes that are at least as extensive in North
America, Asia and Australia. IT companies such as Google, IBM, Intel and
Microsoft are also making significant investments in quantum