In a second visionary speech in 1981, Feynman developed what is perhaps an even more radical idea: a whole new kind of computer, called a “quantum computer”, which would make today’s high-powered computers look like the Commodore 64 from the early 1980s.
The two main differences between a quantum computer and today’s computers are:
- In the quantum computer, information processing and storage no longer occur by means of electron currents, but are based on the control and steering of single quantum particles.
- Thanks to the quantum effect of superposition, a quantum computer can calculate on numerous quantum states, called quantum bits (qubits), at the same time. Instead of being constrained to the states 0 and 1 and processing each bit separately, the possible states that can be processed in one step are thereby multiplied in a quantum computer.
This allows an unimaginably higher computing speed than today’s computers.
While quantum computer technology is still in its infancy, when it reaches adulthood it will dramatically speed up a variety of algorithms in common use today, such as searching databases, computing complex chemical compounds, or cracking common encryption techniques.
What’s more, there are a number of applications for which today’s computers are still not powerful enough, such as certain complex optimizations and even more so potent machine learning. A quantum computer will prove very useful here. And at this point the quantum computer will meet another ground-breaking future technology: the development of artificial intelligence.
In quantum physics, Richard Feynman no longer saw just the epitome of the abstract, but very concrete future technological possibilities—this is what Quantum Physics 2.0 is about. As Feynman predicted almost 60 years ago, we already use a variety of quantum-physics-based technologies today.
Common electronic components, integrated circuits on semiconductor chips, lasers, electron microscopes, LED lights, special solid state properties such as superconductivity, special chemical compounds, and even magnetic resonance tomography are essentially based on the properties of large ensembles of quantum particles and the possibilities for controlling them: steered flow of many electrons, targeted excitation of many photons, and measurement of the nuclear spin of many atoms.
Concrete examples are the tunnel effect in modern transistors, the coherence of photons in lasers, the spin properties of the atoms in magnetic resonance tomography, Bose–Einstein condensation, or the discrete quantum leaps in an atomic clock.
Physicists and engineers have long since become accustomed to bizarre quantum effects such as quantum tunneling, the fact that many billions of particles can be synchronized as if by magic, and the wave character of matter.
For the statistical behavior of an ensemble of many quantum particles can be well captured using the established quantum theory given by Schrödinger’s equation, now 90 years old, and the underlying processes are still somewhat descriptive. They constitute the basis of the first generation of quantum technologies.
The emerging second generation of quantum technologies, on the other hand, is based on something completely new: the directed preparation, control, manipulation, and subsequent selection of states of individual quantum particles and their interactions with each other.
Of crucial importance here is one of the strangest phenomena in the quantum world, which already troubled the founding fathers of quantum theory.
With entanglement, precisely that quality of the quantum world comes into focus which so profoundly confused early quantum theorists such Einstein, Bohr, and others, and whose fundamental significance physicists did not fully recognize until many years after the first formulation of quantum theory.
It describes how a finite number of quantum particles can be in a state in which they behave as if linked to each other by some kind of invisible connection, even when they are physically far apart.
It took nearly fifty years for physicists to get a proper understanding of this strange phenomenon of the quantum world and its violation of the locality principle, so familiar to us, which says that, causally, physical effects only affect their immediate neighborhoods. To many physicists it still looks like magic even today.
No less magical are the technologies that will become possible by exploiting this quantum phenomenon.
In recent years, many research centers for quantum technology have sprung up around the world, and many government funded projects with billions in grants have been launched. Moreover, high tech companies have long since been aware of the new possibilities raised by quantum technologies.
Companies like IBM, Google, and Microsoft are recognizing the huge potential revenues and are thus investing heavily in research on how to exploit entangled quantum states and superposition in technological applications.
Examples include Google’s partnerships with many academic research groups, the Canadian company D-Wave Systems Quantum Computing, and the investments of many UK companies in the UK National Quantum Technologies Program.
In May 2016, 3,400 scientists signed the Quantum Manifesto, an initiative to promote co-ordination between academia and industry to research and develop new quantum technologies in Europe. Its goal is the research and successful commercial exploitation of new quantum effects.
This manifesto aimed to draw the attention of politicians to the fact that Europe is in danger of falling behind in the research and development of quantum technologies. China, for example, now dominates the field of quantum communication, and US firms lead in the development of quantum computers.
This plea has proved successful because the EU Commission has decided to promote a flagship project for research into quantum technologies with a billion euros over the next ten years. That’s a lot of money given the chronically weak financial situation in European countries.
The project focuses on four areas: communication, computing, sensors, and simulations. The ultimate goal is the development of a quantum computer.
The EU is funding a dedicated project on quantum technologies with one billion euros over ten years. Politicians have high expectations from this area of research. No wonder such a lot of money is being put into this field of research, as unimaginable advantages will reward the first to apply and patent quantum effects as the basis for new technologies.
Here are some examples of such applications, the basics of which physicists do not yet fully understand:
• The quantum Hall effect discovered in the 1980s and 1990s (including the fractional quantum Hall effect). These discoveries were rewarded by Nobel Prizes in 1985 and 1998, respectively. This states that it is not only energy that is emitted in packets, but at sufficiently low temperatures, the voltage that is generated in a conductor carrying an electric current in a magnetic field (classic Hall effect) is also quantized. This effect makes possible high-precision measurements of electric current and resistance.
• New miraculous substances such as graphene, which are very good conductors of electricity and heat and are at the same time up to two hundred times stronger than the strongest type of steel (Nobel Prize 2010). Graphene can be used in electronic systems and could make computers more powerful by several orders of magnitude.
• Measuring devices based on the fact that even very small forces, such as they occur in ultra-weak electric, magnetic, and gravitational fields, have a quantifiable influence on the quantum states of entangled particles.
• Quantum cryptography, which is based on the phenomenon of particle entanglement (Nobel Prize 2012) and allows absolutely secure encryption. By considering the last two examples, we shall show what dramatic effects the new quantum technologies, even apart from the quantum computer, may have on our everyday lives.
You may also want to read more about Quantum Computing here.
