In the current hype about quantum computers, people tend to forget that the technology is still a long way from everyday, practical use. What questions are still open? And why is it nevertheless important to get to grips with the subject now?

It sounds almost too good to be true: You boot up a quantum computer, feed it lots of data and tasks - and just a few moments later, the high-tech mastermind spits out results for which even today's high-performance computers often still need hours, days or even weeks of computing time. There's hardly a newspaper or news portal these days that isn't reporting on the wondrous promise of quantum computing. The use of the technology seems to be the next big thing, there is talk of a real revolution, the German government is promising billions in funding, and the financial press likes to hype about a "mega opportunity for investors."

In the current hype about quantum computers, people tend to forget that the technology is still a long way from everyday, practical use - even though research and development have made huge progress in this area in recent years. In any case, there are plenty of potential fields of application for quantum computers: chemical or pharmaceutical simulations, for example, can be significantly accelerated. In the long term, quantum computers could also be used to estimate the potential of new drugs or vaccines much more precisely and quickly than is usually the case today. However, current quantum computers are still far from being used today in the search for new vaccines, for example against Covid-19.

Entirely new materials, for example for use in automobile production, could be developed faster and more cost-effectively than previously possible thanks to quantum technology. For example, a further technological leap in the long term would be conceivable in the field of battery and fuel cell research; a better material design calculated by quantum computers would enable higher power and energy densities. And quantum computers should also be extremely interesting for banks and financial service providers: Highly complex financial mathematical calculations would be feasible in real time in the future.

Waiting for the qubits

The reason why we will probably have to wait a while longer for a real breakthrough with quantum computers is due, for example, to the new type of quantum bits - "qubits" for short. A qubit is basically the equivalent of a classical bit in a conventional computer - only more powerful by an enormous factor. This makes it possible to perform complex computing operations in fractions of a second that would sometimes take hours or days on conventional computer chips.

Some time ago, developers at Google succeeded in generating breathtaking computing results on a quantum computer with only a few dozen qubits. For everyday applications in industry and science, however, a few dozen qubits are often still too few. Especially since these qubits are very fragile. As of today, the quantum systems are still error-prone. This is also one of the main problems with quantum computers. In order to be able to run practical applications on quantum computers, hundreds, perhaps even thousands of error-corrected qubits are needed so that reliable and precise results can be delivered in the end.

To bridge the long development time, initial experiments are already being conducted on existing error-corrected quantum computers - so-called noisy intermediate-scale quantum (NISQ) computers - to test the novel technology. There is still a lot of scientific work to be done in this field before practical quantum computer systems are available on the market, which must then also be affordable and operable.

Without trained users, the best system is useless

Behind the inconspicuous word "operable" lies another challenge: it will hardly be possible to operate a quantum computer sensibly with conventional software. It is already foreseeable today: New software concepts and a completely new way of thinking on the part of developers are necessary in order to be able to use quantum technology at all. Without appropriately trained users, ideally with a scientific background, even the fastest computer in the world will be useless.

There is no question that quantum technology has the potential to revolutionize entire sectors of the economy or parts of it. However, there is still a long way to go before quantum computers will find their way into everyday life, especially in research and science, but also into research departments in industries such as finance, pharmaceuticals, chemicals or energy. And even if it is likely to be several years before quantum computers are suitable for everyday use, companies should start looking at them today if they do not want to be left behind in the next industrial revolution.

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