Often seen as a mysterious and revolutionary technology, quantum computing has reached a crucial milestone thanks to a major breakthrough in the field of quantum entanglement. Researchers have set a new record by entangling 24 logical qubits, a feat which represents a decisive step towards the creation of reliable and efficient quantum computers.
What is a qubit, and why is it so special?
Classical computers work using bits, these units of information which only know two states: 0 or 1. It's simple, straightforward and has helped create the digital world we know today. However, to solve certain complex problems, such as simulating molecules in chemistry or optimizing giant logistics networks, this simplicity reaches its limits.
This is where qubits come in, generated by manipulating physical systems at the atomic or subatomic scale. Unlike classical bits, qubits can be in a state of 0of 1 or… both at the same time thanks to a phenomenon called superposition. Imagine searching for a hidden object in a room: a classical computer would have to inspect each corner one by one, while a quantum computer could explore the entire room simultaneously.
That's not all. Qubits have another extraordinary property:entanglement. This phenomenon makes it possible to link two qubits in such a way that no matter the distance that separates them, the state of one will instantly depend on the other. Through entanglement, quantum computers can solve certain problems by exploiting complex connections between qubits, thereby multiplying their computational capacity far beyond what is possible with classical systems.
This immense power opens up revolutionary perspectives, but it is accompanied by major technical challenges, notably the fragility of qubits and the difficulty of maintaining their coherence.
The fragility of qubits: why is it a problem?
Qubits are incredibly sensitive. They can lose their state in a fraction of a second due to noise, vibration or even minimal electrical disturbances. This loss of stability, called loss of consistencymakes the calculations imprecise, or even unusable. Moreover, the entanglementone of the key elements in the functioning of quantum computers, is equally fragile. Entanglement connects qubits in such a way that the state of one depends directly on that of the other, even remotely. Without this quantum entanglement, a quantum computer is just a machine expensive and inefficient.
To make these machines operational, researchers had to find solutions to protect the qubits from errors. This is where the logical qubits come into play.
The logical qubit solution: what is it?
Imagine that you are writing an important sentence. If one letter is erased, the rest of the text can still give meaning to your message. Logical qubits work on a similar principle. Instead of using an isolated qubit to perform a calculation, they combine multiple physical qubits. This redundancy allows errors to be detected and corrected automatically, even if one or two qubits fail. This helps ensure much greater stability and precision, finally making quantum calculations workable.
Researchers recently entangled 24. This is the highest number ever reached to date. Entangling so many logical qubits may seem trivial to the uninitiated, but it is a monumental technical feat. Until now, researchers had difficulty entangling even a handful of them while maintaining error correction.
How did they do it?
The researchers achieved this feat through a combination of cutting-edge technologies that make quantum systems more stable and reliable. On the one hand, they used the neutral atom quantum processor developed by Atom Computing. This device employs individual atoms precisely manipulated by lasers to store and process information. These neutral atoms, due to their lack of electrical charge, are naturally more resistant to external disturbances, making them an ideal basis for stable qubits.
On the other side, the qubit virtualization platform created by Microsoft played a key role. This sophisticated software detects and corrects errors in real time, a major challenge in quantum computing. By ensuring that logical qubits remain reliable even during complex calculations, this technology helps stabilize quantum systems.
The synergy between these two advances allowed researchers to demonstrate that it is possible to build error-tolerant quantum systems capable of operating efficiently on commercial machines. This represents an important step towards making large-scale quantum computing a reality.
What are the impacts for the future?
Although quantum computing is not yet within reach of the general public, the implications of this advance are considerable and could revolutionize several fields. For example, in chemistry and materials science, quantum computers would make it possible to simulate complex molecules with unprecedented precision, which would facilitate the discovery of new drugs or revolutionary materials.
In the finance sector, they would offer powerful tools for optimizing investment portfolios and solving financial modeling problems that are far too complex for current systems. Logistics and optimization would also benefit from these machines, capable of planning routes or perfecting supply chains on an unimaginable scale.
Another key area is cryptography. Quantum computing could both enhance security with tamper-proof systems and threaten current technologies by making certain algorithms obsolete.
Finally, these computers could play a crucial role in accelerating scientific discoveries, opening up previously unimagined perspectives in areas ranging from fundamental physics to artificial intelligence.
