The year has started with great quantum ads. After Google presented its Willow chip, to which the multinational attributes the ability to solve in five minutes a task that a supercomputer would take four years, Microsoft has affirmed that it has found a new state of the subject with which to tame the elusive particle of Majorana. Now, a team of scientists from Amazon Web Services (AWS) and Caltech shows in Nature To Ocelot, a new quantum computing processor that, according to the company, can “reduce error correction costs by up to 90%.” All appeal to have reached achievements that anticipate a new era of computing. However, scientists outside companies have welcomed ads with coldness and caution. Is it a quantum bubble?
Monit Sharma, a research engineer of Indian origin of only 23 years, has been distinguished in the Singapore Management University (SMU) by the application of quantum computing to real -life problems. However, Sharma is cautious and considers that this technology is not yet able to address large -scale real scenarios. “I think they will need at least two decades so that hardware [equipos] Be at a good level so that at least problems of decent size can be tested, ”he says.
On the contrary, OSKAR PANINTER, AWS HARDWARE QUANTUM HARDUME director, after the presentation of Ocelot: “With the recent advances in quantum research, quantum computers tolerant of failures will be available for real world applications. Ocelot is an important step on that trip. In the future, quantum chips built according to the Ocelot architecture could cost as little as a fifth of the current ones, due to the drastically reduced amount of resources necessary for the correction of errors. Specifically, we believe that this will accelerate the achievement of a practical quantum computer in five years. ”
The basis of quantum computing is the superposition of states, the capacity of the particles, such as an electron or a photon, to exist in multiple states at the same time. This property configures the cubit (quantum basic unit), with an exponentially greater capacity than classic bits, which can only be in two states: zero or one. But any interference, called “noise” (can be a temperature change or the simple Wi -Fi network, for example), cancels this overlap that the physicist Erwin Schrödinger simplified with the famous cat that can be alive and dead at the same time.
In this way, two of the keys to quantum computing is the development of robust chips that maintain or take advantage of the fragile and ephemeral coherence of the cubits against noise and, knowing that errors, the correction of these will occur.
It is the path chosen by Google with Willow, by IBM with Heron, a 133 cubits chip developed for its interconnection and based on an architecture known as “Tunable Coupler”, And by AWS with Ocelot. The objective is to develop quantum computers capable of making reliable calculations, without errors, and significant complexity. “The biggest challenge is not to build more cubits, but to make work reliably,” says Painter.
The other way is the one announced by Microsoft, which claims to have found a new state of matter: the Majorana, a theoretical proposal of Ettore Majorana 88 years ago and describes a particle capable of protecting the environment (noise) the quantum information and, therefore, making error correction unnecessary. This has not yet been achieved, according to most physicists.
A team from the Materials Institute of Madrid (ICMM-CSIC), formed by Elsa Prada, Ramón Aguado and Pablo San José, in collaboration with the Institute of Science and Technology of Austria (ISTA), the Catalan Institute of Nanoscience and Nanotechnology (ICN2) and the University of Princeton in the United States, has sought this Holy Quantum Graial. But unlike Microsoft, they have submitted the results of their investigations to multiple checks until they determined, as published in Naturewho have managed to find an impostor, a particle that mimics behaviors of Majorana, but it is not.
The Spanish scientist is skeptical after Microsoft’s announcement. It defends the importance of majoranas as “new quantum state of matter” and admits that their finding would be key to the development of topological cubits, “immune to decoherence [la pérdida de la superposición de estados]” But he warns: “There really is a lot of exaggeration and misinformation in the field [de la computación cuántica] And it is important to be precise and rigorous if we want scientists to take us seriously, ”says Aguado.
“Why this skepticism?” He asks in his own publication. Aguado recalls that Majorana’s previous detections “turned out to be false positive (Andreev linked states within the space of a superconductor), which made the conclusive detection extremely challenging.” “Our group has contributed greatly to clarify this debate,” he adds.
“Have Majoranas detected? If the word game forgive me, they have seen many times in the magazine Naturebut maybe not so many times in the true mother nature, ”
And he concludes: “Let’s be clear: the Microsoft document has not demonstrated a single cubit (topological or other) not even an irrefutable test of majoranas on its device. When fully biased news, press releases and the like that contain such exaggerated statements, scratches in absolute falsehood, becomes increasingly easy to discredit science, scientists and generate false news on other more important issues for society. ”
The theoretical physics professor at the King’s College in London, George Booth, is less sharp (“they do not demonstrate unequivocally that they can measure a complete topological cubit, but they approach a viable topological cubit,” he says). However, remember that, in Microsoft’s 20 years of research on this path, some articles had to be removed by errors.
Also the young scientist Monit Sharma adds to the group of caution expressed by Aguado: “I think it is essential to communicate in a responsible way what the quantum can and cannot do today. Achieve quantum advantage [resolver un problema de manera significativamente más rápida que cualquier supercomputadora clásica]or more ambitiously, quantum supremacy [resolver un problema imposible para un ordenador convencional] For practical tasks, it is a marathon, not a speed race. ”
On the contrary, Ocelot Oskar Painr researcher, professor of Physics at Caltech and head of hardware Quantum in AWS, it does defend the rapid advances: “The error rates have decreased by a factor of two each biennium. At this rhythm, it would take us 70 years to get where we need to be. Instead, we are developing a new chips architecture that can be able to take us there faster. ” “That said, this is one of the first construction blocks. We still have a lot of work to do, ”he admits.
Something more cautious and in the Shamar line Fernando Brandão, PAINTER researchmate in AWS and CALTECH is pronounced, in addition to co -author of work on Ocelot: “We are in a long -term search to build a useful quantum computer to do things that even the best supercomputer cannot do, but expand them is a great challenge.”
