Terry Rudolph is professor of quantum physics at Imperial College London. It seems to have discovered only after graduation that I have how many in the DNA: in fact Erwin Schrödinger was his grandfather, for part of his mother. In his book Q is for quantum, published in Italian by Adelphi with the title Quan, he tries to “help people understand the philosophically strangest aspects of theory, without orienting them towards what they mean; Also because, despite millions of words spent on the subject, nobody really knows ». For years he has been dealing with quantum computers and in 2016 he co -founded the Psquantum, a company based in Silicon Valley.
Professor Rudolph, quantum physics is often considered a complicated theory, far from reality. Is that so?
«When he observes a cup of coffee in front of her, he knows that he has many physical properties: how high it is, how high it is and how wide it is, how much it weighs, what color it is, if the liquid inside is sweet or not, etc. Now, I’m here in San Francisco, to ten thousand kilometers away from her. Images if I told her that the properties of your cup of coffee also depend on what I will eat for lunch … this would seem strange. Here, when we apply the quantum theory to the physical properties of the particles, sometimes we discover things like these; Which makes it complicated to understand what the theory is telling us about the real physical properties of things ».
But what are your applications in everyday life?
«First of all, the laser, which is a very particular quantum state of the light particles, photons. Without laser we would not have the internet: all communication on large distances takes place through laser light, transported along the optical fiber. Then there are the transistors, which are the basis of all digital technologies: without transistors, computers would not exist. And their properties are due to the quantum effects of the way the electrons move within materials such as silicon ».
What else?
«Atomic watches. To measure time in a very accurate way we must resort to quantum effects in atoms ».
Not a common problem …
«But without quantum watches there would be no GPS. In order for the GPS to work, in fact, we must measure very short time intervals, those among the satellite signals, in a very precise way. And there are applications in medicine ».
As?
«Thanks to superconductors. When we go to make a magnetic resonance imaging, they put us in a big magnet; And this magnet is possible because of the quantum effects in a material that we call superconductor. Then, all drugs depend on chemistry and understand chemistry is possible only thanks to quantum theory. Therefore, even if people can think that quantum theory is a strange and esoteric corner of physics, it is actually something very important in our modern lives ».
Are there other important technologies based on the quantum?
«Our world depends on being able to build good computers. Not for Instagram or to book the restaurant: our computational ability influences as we design and build cities, as we predict the weather, how we produce and control energy, as we discover medicines. And to solve these important problems we need those enormous and expensive tools called supercomputer. Here, among the fundamental technologies based on quantum effects there is another, which we still do not have but that we want strongly: the quantum computer ».
Why do we want it so much?
«First of all, a quantum computer would not replace our laptop, but some supercomputer. It would make calculations that normal supercomputer would never be able to do and would allow us to progress in many areas, such as chemistry or material science, replacing our slow and imprecise experiments “.
Why is it so difficult to make it?
«Because it uses much more complicated quantum effects than those of atomic or laser watches; It must also be very large. Now, one of the peculiar aspects of quantum theory is that the effects are very sensitive to being observed, that is, measured. And when we begin to build a large quantum computer there are so many particles involved that becomes difficult to make sure that they are not inadvertently observed before the computation has ended … and this is the reason why its construction represents an engineering challenge that many companies are trying to solve “.
In which other areas can the theory be applied in the future?
«There are two sectors that we expect are revolutionized by quantum computers: the science of materials and the biochemistry, that is, the chemistry of the living. Observe the building in which it is located: many different materials contribute to its structure, such as glass, cement, etc. Think of the immense effort made by many people and how much energy it has served to build it. In short, a modern building looks like an incredible enterprise of engineering and engineering skills. But do we really know everything that is known about this process? ».
It seems to understand no …
“Here you are. And now think of a seed that falls into the ground. It grows and becomes a tree one hundred meters high, only through water, air and sunlight. It can resist for a thousand years and even cure itself alone. Our buildings are of an almost trivial simplicity, compared. In short, we are only in the beginning of the understanding of the chemistry and the science of possible materials in this universe; And a quantum computer would be essential to help us on this journey ».
What can we expect?
“Even for a huge and very expensive supercomputer today it is impossible to make accurate predictions about what happens for example when we make certain molecules and certain materials interact … For now we must continue to have experiments, which are slow, expensive and confused. And this slows down the design of new drugs, or the production of better batteries for electric vehicles, or even a simple thing like producing fertilizers ».
The most fascinating perspectives?
«So far we have focused on technology and engineering. But since all existence depends on chemistry and chemistry depends on quantum physics, there will be many practical implications deriving from an increasing understanding of quantum theory. Speculating on where quantum technology will bring us in the future is dangerous, but I hope in a second industrial revolution, which is more in harmony with nature, just like the tree we have spoken of … even if, for a scientist, quantum theory is wonderfully strange even only from a philosophical point of view “.
Is it revolutionary in itself?
“Let’s say that it is not that kind of something that would ever come to mind, if we had had to invent the rules of the universe.”