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.

I am an expert in cybersecurity. Nowadays, practically our whole life is connected to the internet: personal information, financial data, etc. In order to protect our privacy, we need to develop and improve the cryptographic methods we have.

I am worried that quantum computers will jeopardise this security, but it is a relief to know that quantum physics also provides us with tools to exchange information securely, regardless of how powerful computers are and will be.

We cannot describe the properties of two entangled particles separately.

If we measure the polarisation of a photon (the plane of oscillation of a light wave), the polarisation of the entangled photon will also be instantly determined!

We can only entangle quantum particles, which we can use to teleport information, for example.

Applications: this is the basis for most of the new quantum technologies, such as computing and cryptography.

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.

MRI (magnetic resonance imaging) scanners work thanks to the interaction of some of the particles in our body (hydrogen atoms) with very intense magnetic fields.

This technique is widely used in medicine to obtain images of soft tissues, such as joints and tendons. It is also useful to obtain detailed brain images that make it possible to identify aneurysms and tumours.

In order to send an encrypted message, you must have a key to encrypt and decrypt the message. The challenge for the receiver and the sender is to share the key without it being intercepted.

Thanks to superposition and the effect of measurement on quantum systems, we can share keys securely and remotely.

Quantum key distribution systems can even detect the eventual presence of spies.

There are various companies (among which LuxQuanta and Quside,  ICFO spin-off companies) that already offer cryptographic commercial services based on quantum physics.

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?

Many people argue that knowledge should be owned by all of humanity together. On the other hand, the development of applications often takes place in industry, which makes vast investments in exchange for an economic return, which results in the privatisation of knowledge.

How can public and private interests be combined in scientific research?

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.