Scientists at 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 a period of approximately one 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 [for electricity] at a temperature close to room temperature, we will be able to contribute to solving problems related to energy transport,” declares Leticia Tarruell, Icrea researcher at the ICFO and director of the project.
Among the two types of quantum computers that are being developed in the world, the one from the Castelldefels Photonics Institute is part of the group of quantum simulators. These are devices that compute with atoms, taking advantage of their quantum properties, and thus solve physics problems. It differs from programmable quantum computers, more similar to a conventional computer, which execute algorithms.
The idea of creating quantum simulators was proposed in 1981 by legendary physicist Richard Feynman of the California Institute of Technology, who argued that a quantum computer would be better than a conventional one at solving quantum problems.
The main advance of the ICFO quantum computer compared to previous devices is that it uses strontium atoms to carry out its calculations. “Strontium is an element that is used in atomic clocks and has the advantage that it allows ultra-precise measurements to be made,” 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 because these other atoms compute with qubits, or quantum bits, in which the information can be encoded in two states, such as zeros and ones. But the strontium atoms of the Quione computer not only adopt two states but can adopt up to ten. Technically it is said to compute with qudits, with a d instead of a b.
It is expected that the computing capacity of quantum computers will surpass that of any conventional supercomputer in the future.
Although the Quione's processor does not measure even a square millimeter, “it is quite large,” Tarruell is proud. It consists of about 300 strontium atoms, which will allow enormous calculations to be carried out.
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.
Cooling is achieved by bombarding the atoms with lasers to immobilize them. Also using lasers, each atom is placed in the right place, next to each other in a grid like eggs in an egg cup. From there, you see how each individual atom behaves.
“For now we have developed the device, and we work on it every day to improve it, but we have not yet used it to solve any specific physical problem,” reports 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 specialized 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,” highlights Lluís Torner, director of the ICFO, who has not participated directly in the research. “A simulator-type quantum computer is an instrument to study the physical properties of certain materials at an unprecedented level and to design better materials at the atomic level. “Spain will be among the first countries in the world to have this technology and to develop quantum computing based on strontium atoms.”
