“Quantum particles live in a kind of suspended reality,” says Serge Harroche. It speaks naturally to someone who has spent more than 50 years studying how light and matter interact on their most intimate scale. The French physicist – who won the Nobel Prize in this specialty in 2012 – arrived in Buenos Aires to participate in the course. “The role of science in the development of modern societies”It is a meeting that brought together teams on vaccines, quantum physics, health and science education.
Haroche, who was interviewed by Nationwon the Nobel Prize for Development Experimental methods for observing and controlling individual photons without destroying themThis is an achievement that made it possible to prove quantum effects that previously existed only as theoretical ideas. Share it with David Wineland. In other words: He was one of the first to capture the light to study its deepest secrets.
This event was organized by National Academy of Exact, Physical and Natural Sciences (Be fair)the National Academy of Sciences of Argentinathe French Academy of Sciencesthe French Embassy in Argentinahe French Institute in ArgentinaNational Interuniversity Council (sin) and the Faculties of Exact and Natural Sciences and Medicine of the University of Buenos Aires (UBA).
To understand their work, you have to imagine an everyday situation: everyone rolls a dice, in different parts of the world, and they always get the same number. This impossible behavior is an honest metaphor for Quantum entanglementIt is a deep connection that unites certain molecules even when they are far apart. Before they are measured, in addition to these particles They do not have a specific country: It can be 0 and 1 at the same time, which is called Quantum superposition. Haroche has dedicated his career to observing and manipulating these natural anomalies, proving that they are not fiction, but real physics.
This possibility opened the way to something he considered essential:… Quantitative communication. What is this? A method of sending secret keys using pairs of entangled particles. Since these particles “copy” each other, both ends receive the same random sequence of 0s and 1s. This sequence is used as the password. The extraordinary thing is that No one can spy on her: If someone tried to observe it, nature itself would destroy the quantum state. Haroche sums it up like this: “The key doesn’t exist until someone measures.”
With this simple and radical idea, Quantum communications promises unhackable systems. They are already working in real demonstrations, although the speed and stability of the process still needs improvement. Haroche himself has dedicated his life to creating the conditions that allow these kinds of experiments: vacuum chambers, isolated atoms, photons trapped between perfect mirrors.
His journey also crossed the laser, the instrument that witnessed the birth of and transformed all of modern physics.. Using lasers, physicists built atomic clocks a billion times more accurate than a pendulum, manipulated atoms one by one, tested general relativity with extremely high precision, and ultimately performed experiments that Einstein and Schrödinger had envisioned as impossible dreams. “The laser has created a virtuous circle: basic science invents a tool, the tool enables new observations, and those observations feed more science,” he says.
Today, in addition to closely following progress in his field, he carefully monitors the frontiers of other disciplines: genome editing, gravitational wave astronomy, and the search for exoplanets. He is also concerned about the progress of anti-science movements. “Knowledge is not the same as wisdom,” he says. “Science is neutral, and what we do with it is an ethical problem.”
—How do you explain in a simple way your field of study and how it can affect your daily life?
-I work in quantum physics. I study how very simple atoms – real or artificial – interact with light, with photons, and how they obey the strange rules of quantum physics. The idea is to manipulate isolated quantum systems to learn how they work, and one day use those properties in new devices. this It may have applications in communications, computing, or quantum simulation. My area is called quantum information, and that’s where I mainly focus Quantitative communication.
— Can you explain in a simple way how quantum communication works?
-Classical communication uses photons transmitted via optical fibers. In quantum communication we use a phenomenon called Quantum entanglement. When two systems are intertwined, they remain interconnected even if they are apart. Before it is measured, it can be in several states at the same time: this is called Quantum superposition. When measuring, the system gives a result that can be random: it can be 0 or 1. If you share entangled pairs, both sides receive the same random sequence. This sequence acts as a key to encrypt and decrypt messages. The advantage is that No one can spy on the key: It does not exist until you measure. The challenge is to transfer these keys without too much noise and preserve quantum properties.
Why is quantum computing advancing more slowly than quantum communications?
-Because it is much more difficult. A qubit can be at 0, 1, or a superposition of both. Multiple qubits can talk to each other through entanglement. This allows for more efficient algorithms than classical algorithms. But maintaining this entanglement is very fragile. When the system interacts with the outside world Decoherencewhich destroys quantum properties. A quantum computer needs to be isolated from the environment and, at the same time, connected to the world to read information. It is a very delicate balance and has not yet been achieved on a large scale.
—I started working with lasers when they were just being invented. What did they contribute to science?
—When I arrived at the lab, in the mid-1960s, lasers had just appeared. We immediately realized that it would allow us to perform spectroscopy with greater precision. Today’s lasers make it possible to build incredibly accurate atomic clocks, test general relativity, and trap and manipulate atoms one by one. What is striking is that many of these ideas were imagined by Einstein, Heisenberg, or Schrödinger as impossible experiments.. But technology has made them real. Lasers show how basic science allows us to create tools that in turn allow us to discover more basic science: it’s a virtuous circle.
-Can artificial intelligence be applied in your field of study?
-Yes. Artificial Intelligence is a tool with a huge memory and can process huge amounts of information. It can classify physical phenomena, detect anomalies, improve experiments, or suggest new ones. In my area, it can help understand systems containing many entangled qubits. but, Although AI is very useful, I believe we will always need scientists. Curiosity is human. The emotions that drive the research are not owned by the machine.
-What developments in other disciplines are most surprising to you?
—There are major advances in biology and genomics: the possibility of modifying the human genome to treat diseases represents a huge advance. AI also helps predict how proteins will fold based on their sequences. In astronomy, gravitational waves open a new window to study the universe and understand how black holes form and disappear. Searching for exoplanets is also cool: using very precise spectroscopy, you can detect elements like oxygen or nitrogen on distant planets, and see if they could harbor life.
—In these years, anti-science movements grew. because?
-I think so Humanity is at a critical moment: climate change, geopolitical tensions, and an aging population. Many people feel excluded from these changes, and this generates fear and resentment. It is fertile ground for anti-science rhetoric. Artificial intelligence also affects: some people fear losing their jobs or not adapting to a rapidly changing world. Science communication can help, but the solution requires politicians to understand the importance of investing in education and science. This is difficult in democratic systems, because short-term logic prevails..
– You said that “knowledge is not the same as wisdom.” What does he refer to?
—Science is neutral: it produces knowledge. The problem arises when we decide what to do with this knowledge. Nuclear power is a clear example: we cannot erase what we already know, but we can regulate it. The same thing happens with artificial intelligence. We need clear rules to maintain social trust in these technologies. The balance between knowledge and wisdom is one of the great challenges of our time.