A signal that leaves no doubts: The quantum world shows its true face
The border between the classic and the quantum has always been blurred. Between promises of technological revolutions and doubts about their authenticity, quantum computers have lived under suspicion. However, recent evidence provides solid proof that quantum effects are not only real, but also manifest on a large scale.
### A leap beyond classical limits
Up until now, demonstrations were limited to small groups of particles. Seeing Bell correlations in two or three qubits was nearly routine, but scaling that up to dozens of units posed a significantly greater challenge. Researchers from the University of Leiden, Tsinghua, and Zhejiang took a decisive step by certifying unmistakable quantum signals in a 73-qubit processor. This was not a controlled laboratory setting with just a few particles, but rather a complex system approaching the true scenario of practical quantum computing. For the first time, it was proven that these devices do not simulate, but rather operate under the strangest—and most powerful—rules of physics.
### Energy as the hallmark of the quantum
One of the challenges was to verify those correlations without measuring all possible combinations, an unfeasible task even for powerful computers. The team chose an indirect route: observing energy. If the system reaches values lower than those allowed by classical physics, the explanation can only be quantum. The result was clear. The difference from the classical limit left no room for doubt. It was a statistically impossible distance to attribute to chance, turning the experiment into a direct confirmation of what was previously just a conjecture.
### The depth of quantum correlations
The team also measured the so-called “Bell correlation depth,” indicating how many qubits must be simultaneously involved in the non-classical interaction. They managed to certify genuine correlations in up to 24 qubits, a number never before achieved in a real system of this scale. This advancement demonstrates that qubits do not act in isolation, but rather intertwine in an invisible fabric that multiplies the system’s computing power. It is ultimately a technological maturity test that brings quantum computing closer to practical application scenarios.
Confirming the quantum nature of these systems is not just an academic exercise. It could pave the way for secure communications, the design of more efficient algorithms, and more. Bell correlations could become the foundation of an unhackable digital infrastructure and calculation engines for currently unsolvable problems.
What was once an almost philosophical mystery—whether the quantum was real on a large scale—now transforms into a measured and certified fact. With this, the world is entering an era where the border between the possible and the impossible begins to blur.
