In the first 25 years of the 20th century, it became increasingly clear that elemental particles at times behave like waves and at times like particles. Louis Viktor de Broglie combined Planck’s quantum theory, Bohr’s investigations of atoms and Einstein’s understanding of photons as light particles to form the wave-particle duality theory. It became the theoretical bedrock for the first quantum revolution and inventions such as transistors, lasers, microchips, CD players and the Internet.
Thanks to technological progress in photonics, subatomic processes that were already described by scientists 100 years ago can now be measured and controlled. Humanity is thus tapping into a new nanocosmos, where the quantum revolution 2.0 is taking its course. Phenomena such as quantum entanglement, already pointed out by Einstein, play a central role: If two elementary particles are entangled, their properties correlate at all times—even if they are in different places. As elementary particles have wave and particle properties, they can also overlap like waves do and take on several properties at once. This results in an enormous variety of possible combinations of quantum states. This forms the basis for calculating with Qubits instead of Bits, for extremely accurate measuring and sensor technology or for intrinsically secure communication—all those applications at the center of the worldwide quantum revolution 2.0.