I am a historian and a university lecturer.

I think many people put a lot of pressure on scientists to quickly turn their research into applications that benefit society. I think we should not demand results so soon. We should be patient and continue to foster research.

For example, while the theoretical principles on which lasers are based were known back in 1917, it was not until the 1960s that we had the first prototype. It took many more years for it to become an essential technological tool.

I am finishing my secondary school studies and have to decide what to do in the future. I have liked science since I was young, but I do not know which subject to study in college.

I have recently been finding out about progress in the world of quantum physics. It all sounds very promising. I am excited about the idea of being able to be involved in the expansion of scientific knowledge!

In a sense, people who work in science are the explorers of modern times.

We could not understand modern medicine without quantum physics. At the hospital where I work as a doctor, we often use MRI scans to detect tumours and other types of pathologies. Quantum physics is key to understanding this technology's basic processes. In addition, lasers (another quantum technology) have become essential tools for extreme-precision surgery. These are just two examples of how quantum physics can help medicine!

The results of a measurement are probabilistic: we have no way of knowing what will happen when we measure a single particle, but we can accurately calculate the probability of each possible result.

Applications: random numbers. In fact, this is the only way to obtain completely random numbers. Random numbers have applications in cryptography, simulations, gambling, etc.

Quside, an ICFO spin-off, has invented a random number generator based on quantum physics.

It is not possible to measure incompatible observables, such as the position and speed of a particle, at the same time and with arbitrary precision.

This is also known as Heisenberg's uncertainty principle.

The more precise the value of one observable, the more uncertain the other will be. For example, if I know the position of one particle with high precision, then the measurement of its velocity will be highly uncertain (i.e. it will have a large error).

Applications: sensors. We can use this property to obtain ultra-sensitive measurements from magnetic fields or gravity.

Imagine a ball in a bowl. It can escape the bowl only if we push it with sufficient energy; otherwise, it will get to a certain height and fall back.

At quantum scale, particles can overcome certain barriers even if they do not have enough energy. It is as if a tunnel allowed them to cross the barrier without expending energy (tunnel effect).

Applications: electron microscopy (a very thin metal point is placed near a surface and "rips" electrons through the tunnel effect.)

Interferometers are devices that use interference as a tool for very precise measurements.

Quantum properties allow us to further increase accuracy and measure things that are too small for classical physics.

Applications: gravitational waves, super-resolution microscopy, photolithography (printing materials with light), variations in the ground gravitational field (useful for knowing the levels of oil deposits or aquifers).

In principle, quantum physics provides theoretical protocols that are invulnerable to cyber attacks. Nevertheless, some scientists have managed to break the security of existing quantum protocols because of weaknesses in their implementation. Given the finite precision of any human construction, can we rely on theoretical predictions about applications?

It is important for people to be informed about scientific advances so they can express critical opinions about news in the media, advertising, social networks, etc. and avoid falling for scams or misunderstandings. However, sometimes information comes from pseudoscientific sources of dubious reliability.

How should we manage this often dubious information flow?

Their applications in all fields of human activity will radically change our lives, just as electricity and electronics once did. We must invest as much as we can in their development, to make them commercially viable as soon as possible. 

We should not be fooled by illusory promises. We have gone very far with traditional technologies and we still have a long way to go: we should keep the current investment in quantum technologies at the same level. Let scientists do their work and continue to research, focusing on maintaining and improving the technologies that we already have. 

Research into quantum physics and its applications is positive, but we currently have other far more important and pressing issues, such as hunger, poverty, wars and terrorism. Let us maintain research, but invest our money to find solutions to the major problems our society has today.  

Quantum technologies are very promising, but if they are to be effective, they require solid knowledge of their foundations. We should invest in fundamental research: a better understanding of the foundations of quantum physics will naturally lead to the development of its applications.