Segre Aros, 77, said he felt the need to reconsider at the end of his career. He led a team of physicists in Paris who were able to measure light, literally confining it to a box, which earned him the Nobel Prize in Physics in 2012. La Sapienza chose it to keep Enrico Fermi’s lecture course. of a distinguished international scientist who has made significant contributions in specific areas of research. To tell the light that is positioned a little at the end of the story, she started again, starting in Italy and Galileo to get to quantum computers. of Lectures15 in total, from January 27 to May 12, also online at Zoom, showing everyone, not just students and colleagues, the wonders of research that have led to technological revolutions in recent decades.
He arrived in Rome a few months after Giorgio Baresi was awarded the Nobel Prize in Physics. What do you think? “I was very happy. I think it is a good assessment of what La Sapienza and Italy have given to science in general in the modern age. There are great photos of Amaldi, Fermi and even Galileo in my class. But I don’t think countries like Italy and France are investing enough in research and basic science, and I’m sure Giorgio Baresi has emphasized that.
Where does the science of light begin? “When people began to ask deep questions about the nature of light, this was the period in which modern science was born. The seventeenth century is the century of Galileo and Newton. They led to the modern scientific method, observations, experiments, theory and predictions of new influences. This is the virtuous circle between experiment and theory. which have continued together ever since. In the 19th century, new questions led to the theory of relativity and quantum physics. Deep questions about light were the starting point for the theories that revolutionized our lives, not only because they led to better understanding, but also because they led to tools. New, new devices, like lasers, began my career when they were invented 60 years ago. . Unusual technology. “
What are light and gravity for modern science? “Light and gravity are the first things a child notices, gravity is because things fall, and light is because it communicates with the world. And what’s amazing is that we still don’t fully understand it, it’s still there. the difference between the deep levels of quantum physics and the general theory of relativity. Modern research is moving towards combining these two aspects. “
What did light teach us in understanding the world? “At a deep level, we learned that space and time are mixed together, it is impossible to take into account the three dimensions of space, separated by time, until we live in four-dimensional space. When gravity is added to the problem, the space becomes curved and light is scattered along curved lines. But this was realized only a century ago. And before that there were other questions. Light has taught us that electricity and magnetism are closely related and that light is an electromagnetic wave. This led to their reunion 150 years ago with Maxwell. Using light, once we realized that its speed was limited, it was possible to measure the size of the universe.
What do you think are the great visions of the history of the science of light? “I think one of the great ideas was that of Pierre de Fermat, a seventeenth-century scientist in the time of Descartes and Pascal. He said the light propagates along a line that takes the shortest time from one point to another, so it is in a straight line. But if it passes from air to water. , it bends because it “prefers” to pass through the air where it is faster. It was a wonderful intuition: the assumption that light moves slower in water than in air. Another gentleman who had a wonderful intuition, of course, was Einstein, who based the whole theory of relativity on the fact that the speed of light is the same for everyone. But honestly, the intuition of relativity is derived from Galileo, who had it not for light but for the mechanics of bodies if you are on a ship (traveling at a constant speed, so you have no way of knowing if you are moving because experience is not you he says. ”
Difficult and counter-intuitive concepts, from relativity to quantum physics, how are they told to a non-specialized audience? “You have to use metaphors and analogies with known phenomena that people may know. To understand relativity, you need to describe simple experiments that give results that are counterintuitive, but you need to prove that they are true. For example, the so-called “twin paradox”, a twin who leaves and returns at a younger age. Who left him on Earth. In Einstein’s time, it was hard to make him understand. Now we do experiments every day that prove it. Atomic clocks on GPS systems around the Earth are slower for this effect. And if that’s not taken into account, GPS won’t work. “
We come to the research that brought her the Nobel Prize. Did you “touch” the light? “The paradox of light is that when you see it, that light is dead because the photons are damaged when they receive the information, and it becomes a chemical reaction in your eyes. What we were able to do in Paris with my team is to find light without destroying it, and to measure the same photon over and over again, and this can have interesting applications of quantum information.
There is a lot of talk about quantum supercomputer applications. Based on your research, do you see progress ten years after the Nobel Prize? “The fact that a quantum system can be in several states simultaneously, in a state of superposition, suggests different realities, which leads us to the famous Schrödinger cat metaphor. What we have achieved in the laboratory are small copies of this system. If we could do that. To use this phenomenon on a large scale, we will be able to do calculations much faster than a regular computer, but the difficulties are many, one of them is decoherence, the fact that these quantum systems are very fragile and lose these properties very quickly. for ten years and I’m not sure if we can build a quantum computer for practical use in the near future.
On the other hand, there are other systems such as quantum simulators composed of several tens of atoms or particles that can be useful, for example, to obtain superconductivity at high temperatures or to synthesize new molecules to produce new drugs. It uses these anti-intuitive properties of cryptographic communications and quantum cryptography. You can also make systems sensitive to very small interference or probes, which can measure magnetic or gravitational fields with greater sensitivity. This is the new quantum technology. Our search was from the starting points. “
For what applications? “If he had asked Einstein a hundred years ago about the applications of relativity, he would not have been able to predict GPS. Or lasers. The people who made the biggest discoveries were not very familiar with the applications and had never overestimated the predictions … I think I will follow the example.
However, quantum computers seem to be one step away. Is not it like that? “Maybe one day there will be one of these computers, but it must be protected in a chassis, and this is only possible in some parts of the world. It will never be a laptop, but I may be wrong. It tells the story of IBM’s CEO, who for forty years has said there will be room for up to five computers worldwide.
The Sapienza chair, for which he will give his lectures, is named after Enrico Fermi. Scientific discoveries about light have led to great technology, but also to the construction of weapons, the most powerful of which, such as nuclear weapons. Do you think that humanity is more mature now than it was a few decades ago? “I do not think humanity is more mature. When you have power, it can be used to build weapons. Einstein was a pacifist, and yet he signed the letter to Roosevelt, which marked the beginning of the Manhattan Project because it was important at the time that Allied forces were stronger than the Nazis. But science is neither good nor bad, what you do with it is good or bad. For example, those who refuse to look for GMOs or mRNA vaccines because they are “unnatural” are wrong. You need to acquire knowledge and then decide how to use it. You can never stop humanity from feeling curious and knowledgeable Fermi, Curie, physicists of the last century were curious to understand nature and they did, they opened something like a Pandora’s box What we said about weapons may be true and for the Industrial Revolution. we have been using oil and gas for more than a decade and now we are at risk from the climate and that is also the effect of science. “
He doesn’t seem optimistic. “I think we need to understand what real progress is, and we need to steer science in the direction of the problems we need to solve. That is why we need more research and resources. We need to find an alternative to fossil fuels. I think we need nuclear energy because we won’t have enough. “From electricity to replacing cars with fuel with electricity. The sun is not always there and the wind is not always blowing. But to discuss all this, I note that “I do it on the basis of science, but on the basis of ideologies. I am not optimistic because I see that many do not look at problems in a rational way, and the development of fake news and conspiracy theories is going in the opposite direction.”
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