One of my favourite YouTube channels is one in which a young engineer explains how everyday objects work.​

Just yesterday she explained how our cell phones contain lots of transistors and other parts made of semiconductors that are the basic building blocks of digital electronics. All this could not be done without understanding the quantum properties of semiconductor materials that are the basis of these parts.​

I did not know I had quantum technology in my pocket! Yeah!​

I am a biochemist and I research new substances that could become medicines to cure diseases that are currently incurable. ​

One of the lengthier parts of the process of developing apossible new drug is finding out the effects it would have on organisms. ​

If quantum computers would become a reality for their use outside academic settings, we could significantly improve our simulation programs and this could dramatically reduce the need to experiment on living beings.

I am a nurse working in a rural clinic in Ghana. For years, our biggest challenge has been diagnosing patients without access to expensive imaging equipment. Recently, I heard about a new generation of compact, low-cost medical sensors being developed based on quantum technology  devices that could one day detect diseases like tuberculosis or malaria with extraordinary precision using just a small blood sample.​

I don't know when these technologies will reach us, but for the first time I feel like the science being developed in big research centres far away could one day make a real difference here.

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.

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.

Because quantum particles can behave like waves, we can develop matter-wave technologies in which beams of atoms play roles similar to those of light in optical systems. Examples include matter-wave lasers, atomic interferometers, and atomic lenses and mirrors, which exploit the wave-like nature of atoms. ​

The advantage is that such devices are extremely sensitive to tiny variations in gravitational and inertial forces, making them promising for applications such as next-generation accelerometers (the sensors that detect motion and orientation in smartphones and tablets), among others.

Superconductivity is a phenomenon in which certain materials conduct electricity with zero electrical resistance when cooled below a critical temperature. As a result, electric currents can flow without any energy loss. ​

Superconductors are widely used in technologies such as MRI scanners, particle accelerators, and experimental quantum computers. They also make it possible to generate extremely strong magnetic fields and to build ultra‑sensitive detectors.​

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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?

Quantum technologies could revolutionise fields from medicine to secure communications. However, cutting-edge technologies typically reach wealthier nations and communities first.​

Will quantum technologies widen the gap between those who have access to advanced tools and those who don't? How should researchers, institutions and governments ensure that the benefits of scientific progress are distributed fairly?

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.