Physicists have created the first working quantum lie detector

Physicist John Bell has developed a quantum lie detector, the Bell test, which shows whether a quantum computer uses real effects corresponding to it or simply imitates them. This is reported by Science Daily magazine.

With the development of quantum technologies, more and more rigorous quantum tests are becoming necessary. In a new study, scientists raised the bar by testing Bell correlations in systems containing up to 73 qubits, the basic building blocks of a quantum computer.

The analysis involved theoretical physicists Jordi Tour, Patrick Emont, graduate student Menyao Hu from Leiden University, as well as colleagues from Tsinghua University (Beijing) and experimental physicists from Zhejiang University (Hangzhou).

Quantum mechanics is the science that explains how the smallest particles in the universe, such as atoms and electrons, behave. This is a world full of strange and counterintuitive ideas, one of which is quantum nonlocality, in which particles even at a great distance can instantly affect each other. Despite the strangeness, this is a real effect, for which the Nobel Prize in Physics was awarded in 2022.

This study focuses on proving the occurrence of non-local correlations, also known as Bell correlations. It was an extremely ambitious plan, but the well-optimized strategy of the team played a key role. Instead of trying to directly measure complex Bell correlations, they focused on minimizing energy.

In the macrocosm arena: the Nobel Prize in Physics was awarded for the development of quantum technologies

How the study of the tunnel effect at the macro level will help to create a new generation of computers and sensors

As a result, it has borne fruit. The team created a special quantum state using 73 qubits in a superconducting quantum processor and measured energies that were much lower than possible in a classical system. The difference was staggering — 48 standard deviations, which practically eliminates the randomness of the result.

The physicists did not stop there and continued to certify a rare and more complex type of nonlocality known as genuine multicomponent Bell correlations. In this type, all the qubits in the system must be involved, which makes it much more difficult to generate and more difficult to verify. The scientists were able to prepare a whole series of low-energy states that passed the test for 24 qubits, confirming these special correlations with high efficiency.

This study proves that it is possible to certify deep quantum behavior in large, complex systems — this has never been done on such a scale before. This is a big step towards making sure that quantum computers are really quantum. The results are important not only theoretically, as understanding and controlling Bell correlations can improve quantum communication, make cryptography more secure, and help in the development of new quantum algorithms.

Cryostatic figure: Russia has imported a key technology for quantum computers

How new cooling systems will help develop breakthrough solutions in science and technology

On September 26, Science Daily announced the creation of the first working quantum Internet by engineers from the University of Pennsylvania. It was noted that compared to the conventional Internet, where information is transmitted in the form of bits (0 and 1), the quantum uses qubits, which can simultaneously be in several states due to the phenomenon of superposition.

All important news is on the Izvestia channel in the MAX messenger.