Scientists from the Institute of Photonic Sciences (ICFO) have created a quantum computer called Quione with which they hope to solve physics problems that are unapproachable for conventional supercomputers.
The first problem they hope to solve with quantum computing, within about a year, is to better understand what the magnetic properties of certain materials depend on. In the longer term, “our Grail is superconductivity at high temperatures; if we are able to design superconducting materials [of electricity] at a temperature close to room temperature, we will be able to contribute to solving problems related to energy transport", says Leticia Tarruell, Icrea researcher at the ICFO and director of the project.
Between the two types of quantum computers that are being developed in the world, the one from the Institute of Photonics of Castelldefels is part of the group of quantum simulators. These are devices that compute with atoms, taking advantage of quantum properties, and solve physics problems. They differ from programmable quantum computers, which are more like a conventional computer, which run algorithms.
The idea of creating quantum simulators was proposed in 1981 by the legendary physicist Richard Feynman of the California Institute of Technology, who argued that a quantum computer would be better than a conventional one for solving quantum problems.
The main advance of ICFO's quantum computer over previous devices is that it uses strontium atoms to do the calculations. "Strontium is an element used in atomic clocks and has the advantage of allowing ultra-precise measurements", explains Leticia Tarruell. "Another great advantage is that it allows us to have much more computing capacity than processors based on other atoms, such as lithium or potassium."
This greater computing capacity is explained by the fact that these other atoms compute with qubits, or quantum bits, in which information can be encoded in two states, such as zeros and ones. But the strontium atoms in ICFO's Quione computer don't just adopt two states, they can adopt up to ten. Technically, they are said to count with qudits, with a d instead of a b.
The computing capacity of quantum computers is expected to exceed that of any conventional supercomputer in the future.
Even though the Quione's processor doesn't measure a single square millimeter, "it's pretty big", Tarruell is proud. It consists of about 300 strontium atoms, which will allow enormous calculations to be made.
To perform these calculations, atoms must be cooled to ultra-low temperatures, a few nanokelvins above absolute zero, so that they behave like quantum particles and therefore adopt the quantum properties necessary for computing, such as superposition.
The cooling is achieved by bombarding the atoms with lasers to immobilize them. Also using lasers, each atom is placed in the right place, side by side in a grid, like eggs in a nest. From here, we observe how each individual atom behaves.
"For now we have developed the device, on which we work every day to improve it, but we have not yet used it to solve any specific physical problem", informs the researcher.
The research, published on April 18 in the scientific journal PRX Quantum, "is a significant advance in the field of quantum science and technology", the specialist website Quantum Zeitgeist reported the next day.
"The most transformative thing about this advance is what it will allow us to achieve in the coming years", emphasizes Lluís Torner, director of the ICFO, who has not directly participated in the research. “A simulator-type quantum computer is an instrument for studying the physical properties of certain materials at an unprecedented level and for designing better materials at the atomic scale. Spain will be one of the first countries in the world to have this technology and to develop quantum computing based on strontium atoms”.
