I am very excited: I have just won a scholarship to take the Master's Degree in Quantum Science and Technologies in Barcelona.

In addition to learning more about the fascinating world of quantum physics, I will lay the foundation for my career in an expanding field that promises to shape the technologies of the future.

And that is not all: the scholarship will allow me to experience a new country and come into contact with a different culture.

I am a pharmacist and in my work it is essential for my scales to be precise to prepare prescription medicines. For this reason, I recalibrate them every year. When I did it in 2019, I was told that the definition of a kilogram in the International System of Units had changed. The definition of the unit of weight used worldwide is now based on a universal constant, the Planck constant, which plays a fundamental role in quantum physics.

A lot of people are concerned about knowing which interpretation of quantum physics is the right one and truly describes the world we live in. I think this issue is really irrelevant, since the success of quantum physics lies in predicting many phenomena that have been tested experimentally.

Ultimately, this is the only thing that is useful to us and that allows us to keep making progress!

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.)

Many of today's everyday technologies are based on phenomena that can be explained by quantum physics.

Examples: lasers, the transistors that are the basis of electronics, MRI imaging systems, photovoltaic cells, LEDs, GPS, etc.

All of these technologies, which are essential for modern life, are part of what is known as the first quantum revolution.

ICFO is home to some of the coldest places on earth, but no-one can go inside them. In these places the temperature is lower than in deep space: just a few fractions of a degree (hundredths of a nanokelvin) above absolute zero.

Only a few laboratories in the world can reproduce these extreme conditions in small vacuum chambers, where they can trap small numbers of atoms (from a few million to a single atom, depending on the experiment). In order to be able to study the interesting quantum properties that appear at such low temperatures, it is essential for the atoms to be as cold (and therefore as still) as possible.

Photo: One of the ICFO labs where atoms are cooled to close to absolute zero.

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).

Some predictions of scientific theories may require years of research and testing before they are confirmed. For example, it took more than 40 years from the theoretical formulation of lasers to their manufacture, or from the predicted existence of the Higgs boson to its detection.

What if they had given up hope years before and never found it? To what extent is it wise to invest money and effort to confirm a theory when there are so many social challenges that require immediate investment?

An open debate on quantum physics is how it is interpreted. The most common and oldest one (1925-1927) is the Copenhagen interpretation (which we have used in the Info Cards). However, there are other interpretations, such as the many-worlds interpretation (approx. 1960), which suggests that when we perform a measurement, all possible results appear in parallel universes, but we only observe one. One of the problems the interpretations have is that it is not clear whether they are experimentally verifiable.

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.