The computer scientist and philosopher Sergio Boixo has been a centerpiece in the Google team that has reduced to minutes a calculation that requires centuries.
A quantum computer can work better than a conventional supercomputer. This phrase, so simple to write, is a feat that has taken decades of work and contributions from dozens of researchers. The scientific community sensed that it could be reached, but no one had crossed that border. The pioneer who planned the road is a Spanish quantum computer scientist from Google , Sergio Boixo: “We are exploring new scientific frontiers where we have never done experiments before, we feel pioneers,” he says in conversation with EL PAÍS from Mountain View (California).
Quantum computing has lived one of the busiest weeks in its history. The Google team has officially announced that it has achieved quantum supremacy : get a quantum computer to do in a few minutes something that a conventional supercomputer would take thousands of years. Its great commercial competitor, IBM, has questioned the magnitude of the finding, but in the scientific community there is little doubt that the step is an undoubted milestone in that field. "The scientific achievement is huge if it is maintained, and I think it will," said Scott Aaronson, a computer scientist at the University of Texas, in an article in Nature.
“I designed the theoretical part of the experiment,” explains Boixo. “We started working about four years ago. We wanted to show that a fundamental quantum computer can be faster than the world's biggest supercomputers. ” No human had done such a thing before. It's like looking at the future from a place where everything in front is darkness. Boixo carried the flashlight to find the way: “You have to design a measure to verify that the quantum computer works well. It's hard when you're building increasingly powerful quantum computers to do something that has never been done, ”he adds.
When someone is on the frontier of the known, by definition they don't know what's beyond. There may indeed be "fundamental surprises," an impenetrable wall set there by nature: "According to all the theories we know and the developments of the pioneers of quantum computing, we knew no obstacle. However, as you advance in the experiments and apply scientific theories where they have never been applied there is always the possibility that there is a fundamental surprise. ”
One day, in fact, they felt that something like this could be happening. "When we started to collect data and wanted to see a curve predicted by the theory, suddenly the experimental data started to go down and at that time one of the options we thought is that maybe the experiment did not work. In the worst case we find ourselves new physics, we thought. But we said it a little as a joke, we were really worried if it didn't come out, "he explains.
The magnitude of the experiments handled by Boixo's team is an extraordinary leap over previous work: "Previous experiments have shown that quantum computing works with a complexity of a thousand states and in this experiment we have explored a dimension of 10 billion states We have moved the order of complexity by a factor of 10,000 million and must be checked experimentally. "
Boixo, whose official title is chief scientist of quantum computing theory, was the head of Google's computer programmers, but the device itself was in Santa Barbara. Boixo had created the "instructions", but the experimental "vehicle" that allowed him to advance had been done by another Google team.
Boixo came to Google in 2013 and was only the second or third member of the quantum computing team, which is based in Los Angeles. The unit was theoretical but, being Google, they immediately thought that it had to be put into practice. That's when they signed the team of John Martinis in Santa Barbara, because "they had qubits with very good quality." Qubits (quantum bits) are the unit that measures the capacity of a quantum computer.
Boixo's trip to the quantum peak began in León in 1973. In his family there was tradition: his father, Ignacio, is responsible for raising awareness of the staff of the Bank of Spain about the importance of cybersecurity; his grandfather was a pioneer veterinarian in León; her grandmother was passionate about chemistry, and her uncle works at a research center in León. He also started soon: “I remember reading popular science books by Isaac Asimov when I was 12 or 13 years old. As I grew older I was reading more and more technical things, ”he explains.
“I have always had the vocation, but everything in this life requires effort,” he adds. A colleague from the school evokes Sergio's backpack. I always went with scientific books on it, even today. His father remembers telling him on a trip to an ethnic festival in Cáceres: “Sergio, I don't know how you can continue studying in these conditions. It's two in the morning, you have only one light that shines less than a lighter and this is a disco. ”
WHAT IS A QUANTUM COMPUTER FOR?
When Boixo started at the beginning of the century in quantum computing, he was not convinced that he would see such a computer in his career: “Surely he didn't think that in 2019 we would be able to be exceeding the capabilities of the larger supercomputers. It has advanced faster than I expected, ”he says. Boixo's experiment has allowed a quantum computer to make a concrete calculation without errors.
“I have always believed that quantum computers will be a reality and will have a great impact. And I have thought about it because they unite the two most important technological revolutions of the second half of the 20th century: computing and quantum technology, ”he says. The benefits that computers have brought are obvious, but without principles based on quantum physics we would not have semiconductors, lasers or flat screens either.
When quantum computers are programmable and run at full capacity, their capacity will be hard to imagine today. Boixo expects a second industrial revolution of greater energy efficiency that helps combat global warming: “There will be 8,000 or 9,000 million people in the world and with the technologies we have now, not everyone can enjoy a Western lifestyle. With quantum computing we believe that in the long term, chemical, physical processes can be simulated.
Global warming is an energy problem and energy is physical and chemical. Now we are a little blind because there are calculations that we cannot do with classical computing, ”explains Boixo. Quantum computing can allow you to create better batteries, lighter materials that spend less energy.
Number one in engineering
That mentality led him to be number one of the first Complutense Computing Engineering promotion in 1996. His partner remembers him reading the newspaper in class. Boixo explains: “I've always liked to study on my own. Many times I came to class and had already read the book I played or something similar and sometimes I was in the back of class, I paid attention but I could have a newspaper in front because they reviewed something I had already read, ”he says.
His vocational facet did not block the way to sport or the follies of youth. Once in a few weeks he changed hair color and beard three times: from yellow chicken to blue and then purple. "The beard hair fell off so much change," he recalls. While studying computer science, he graduated in Philosophy and Mathematics from the UNED. Before returning to research, he went through private companies and public institutions because he wanted to save before starting his doctorate. “I was at the European Central Bank for internships. They offered me a great job, but I wanted to pursue more scientific concerns. If I stayed, that was going to be my professional career, ”he says.
Before starting his doctorate at the Autonomous University of Bellaterra (Barcelona), Boixo lived about a year in Egypt. I wanted to live in other cultures before getting married. During the conversation he highlights the support he received from his wife during the difficult beginnings of his academic career, with whom he has three children. But Boixo also insists on remembering the role of other Spanish quantum researchers: Darío Gil, today his competitor at IBM; Ignacio Cirac, director of the Max Planck Institute for Quantum Optics, or Diego Porras and Juanjo García Ripoll, of the CSIC.
In Barcelona, he learned quantum physics with Professor Albert Bramon: “He taught me in summer, in his spare time. He told me to read a book and go see him in the afternoon, ”he says. A year later, he was given a scholarship from La Caixa and in 2004 he traveled to the United States to not return. He went to the California Institute of Technology with John Preskill, who coined the concept of quantum supremacy. After a year at Harvard, he pointed out at the University of Southern California, where he worked with a machine considered the first commercial quantum processor. "I was the first quantum programmer they hired to work with such a processor," he recalls. And so it continues, being a pioneer.
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