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Quantum technologies: innovations in a new dimension

The laws of quantum mechanics have held the universe together for 13.8 billion years. For several decades now, people have begun to actively make use of these laws. Since then, quantum technologies have been changing the world.

In the course of the first quantum revolution, multi-billion markets have emerged: digital information technology and data transmission, laser technology, photovoltaics, modern illumination technology, imaging diagnostics and non-destructive quality control are all making use of quantum mechanics, as is the development of new active substances and materials. While this first quantum revolution was based on systematically controlling large quantities of quanta and ultimately using them indirectly, the focus of the second quantum revolution that has now been heralded is direct control and active manipulation of individual quanta. Quanta themselves become an instrument that delivers measurements and sensory information with unprecedented precision, ensuring maximum security in quantum communication and computing power in quantum computing that cannot be achieved with conventional technology.

Quantum technologies and sciences have many applications, including:

  • Quantum computing
  • Quantum simulation
  • Quantum networks
  • Quantum communication
  • Quantum cryptography
  • Quantum sensor technology
  • Quantum imaging
  • Quantum measurement technology

The fundamental principles of all these applications are based on the laws in the dimension of photons, ions, electrons and atoms, which have long been hidden from mankind. Only in the last two centuries have researchers such as Max Planck, Albert Einstein, Werner Heisenberg, Max Born, Louis des Broglie, Richard Feynman, John Stewart Bell and many more brought these laws to light. Today, players in quantum technologies are using these laws to develop computers, communication networks, sensors and measurement technology that go beyond what was previously possible.

Quantum mechanics—a scientific dispute becomes a multi-billion-dollar market

In physics it has long been a matter of dispute: does light consist of waves or particles? Thomas Young’s famous double-slit experiment in 1801 provided initial clarity: when light passes through two µm-thin slits, superposition patterns appear behind them that can only be explained by the diffraction of waves at the two narrow points. But 100 years later, Albert Einstein showed in his Nobel Prize-winning work on the photoelectric effect that light must also consist of particles. If negatively charged metal surfaces are irradiated with white and UV light of the same intensity, only the short-wave UV light releases electrons from the metal. Long-wave light does not cause any discharge. In addition to continuous waves, light must contain quantized packets of energy called photons. Their energy content can be calculated using the frequency and Planck’s quantum of action, which was researched by Max Planck.

Today, physics knows that the paradox of wave-particle duality does not apply only to light. Every quantifiable particle—including electrons, ions and atoms—exhibits this dualism. Louis des Broglie was correct with this hypothesis in 1924, as another double-slit experiment showed: when bombarded with single electrons, an interference pattern appeared behind the double slit that must have originated from diffracted, superposed waves. Conclusion: an electron is also a wave and a particle in one.

On this basis, an ever deeper understanding of the unique laws that govern the quantum world has developed over the last century. These are often hard to grasp: be it superposition states or Heisenberg’s uncertainty principle, according to which two complementary properties of a quantum system cannot be simultaneously expressed in sharply defined values, or be it the “spooky action at a distance” that connects entangled quantum pairs across wide spatial separations. They each have the exact complementary properties of the other; if you measure one, you know the state of the other.

The former scientific dispute has triggered a rapid increase in knowledge. On the basis of quantum mechanics, multi-billion markets have already emerged in the first quantum revolution. The second phase of this revolution is also showing enormous market potential. You can meet the pioneers of both revolutions at World of Quantum and right next door at the Laser World of Photonics.

The didactic physicist Martin Apolin introduces quantum mechanics very clearly in 15 episodes: