Every now and then the word comes to the headlines quantum computer e, a bit like what concerns the conquest and exploration of space, we read about new overtaking and discoveries. If you are not from the field you can have the feeling of being excluded and if when we talk about planets and space rockets at least we are able to imagine them, in the case of computers and their internal mechanisms not even fantasy and some artistic representation can help us. .
Understand though how a quantum computer works it is something that each of us can do, at least in a basic way, to grasp the importance of new discoveries and the progress of the project and get excited about it just like when looking at a victorious space enterprise. In the competition to create cquantum computers Big companies rather than countries face each other more and more powerful and fast, but there are many interests that we would lose ourselves in analyzing, this is not the point we want to deepen.
How a quantum computer works
The latest news speaks of a Google victory over IBM, which the latter denies. I bet that in some time we could very well find ourselves reading the opposite, so let's not chase the news and focus on the protagonist. At the base of the operation of a computer of this type there are the principles of physics and in particular of quantum mechanics. We use what we have discovered over the years about the nature of particles to better process the ever-increasing mass of data that we accumulate and that we want our computer to work.
The fundamental unit is the qubit, it is new, it is different, it is more efficient because it allows us to carry out the calculations simultaneously thanks to the superposition of quantum states. This means that if before we had the bits with the values 1 or 0 and no other alternative, we were forced to a certain type of logic that was based on this duality.
Today, however, with qubits, we no longer have only 0 and 1 as values but many others that are the quantum states that a particle can assume simultaneously with different probabilities. It's like going from a black and white drawing to a color one with a huge range of shades. With this metaphor, imperfect but impactful, we can proceed by stating that there is a new computer science to be written that exploits and takes into account all these states. New laws, new logics, greater power and speed. There are other special properties of these new bits which we call qubits. These different quantum states can interfere with each other, and more importantly, they can intertwine leading to one correlation. These properties are a bit more enigmatic to explain but let's keep them in mind by translating them with the fact that they create even more space for computer experts to "play".
What is the quantum computer for
Let's clarify something right away before starting to dream a quantum computer on our desk in a few years. It's not like the new smartphone model that arrives a few months after its announcement. No, here we have to wait a long time and for now we have projections, forecasts, and a very high consumption of space and energy that certainly would not allow us to each have their own quantum PC in our hands.
The calculations and the re-elaborations with a machine of this kind can be carried out in times absolutely not comparable to those we are used to thinking. Indeed, thanks to the properties of our qubits, i quantum computers they are able to process - at the same time, through parallel computing - multiple solutions to a single problem. Today we can have several solutions but we must calculate one after the other.
Having said that, including that we have an extraordinary machine in our hands, looking at our daily life one wonders "what on earth do we have to calculate so huge?" Here are some examples that make us understand how, even if it will not be on our desk, this computer can improve our lives even in very concrete and everyday aspects. With the great computing power they have, they can dramatically revolutionize the field of cyber security through cryptography, and also that of the much consulted and discussed weather forecast. Even in the very broad field of research, an extra gear in calculations can help, for example those looking for and making new materials.
An example of application of this computer is related to the cyber security and communications-related cryptography. With the tide of data we send and receive today, finding out if someone steals, copies or damages a part of it is very difficult. Yet it is very important to know and prevent it from happening. Thanks to quantum cryptography, it is possible to understand if a bit of information has been intercepted or copied. The properties of light are used to guarantee the security of information transmission, because by exploiting them in an ingenious way that is difficult to explain in a nutshell here, we become able to give the alarm for any violations in real time.
How a quantum computer works and why it is delicate
From the ferocity with which the big names struggle to achieve quantum computers more and more preforming, one can guess that this is not a trivial undertaking at all. It takes a lot of time and money and sometimes it is not enough, you need a brilliant intuition. Today the machines we know we have are still a long way from bringing significant benefits to our society but we are working on them. About ten years and maybe we'll see something.
While very powerful, they are also extremely delicate, a magnetic field little little one can disturb them. Everything connected to the computer must also be redesigned, with huge costs. We certainly cannot use the exact same software as always, we need completely different new ones that still too few know how to design.