Physicists use ‘hyperchaos’ to model complex quantum systems at a fraction of the computing power

Physicists have discovered a potentially revolutionary feature of the behavior of quantum bits that would allow scientists to simulate complex quantum systems without the need for enormous computing power.

For some time, the development of the next generation of quantum computers has been limited by the processing speed of conventional processors. Even the world’s fastest supercomputers haven’t been powerful enough, and existing quantum computers are still too small to be able to model medium-sized quantum structures, such as quantum processors.

However, a team of researchers from the universities of Loughborough, Nottingham and Innopolis have now found a way to circumvent the need for such massive amounts of energy by exploiting the chaotic behavior of qubits – the smallest unit of digital information.

When modeling the behavior of quantum bits (qubits), they found that when an external energy source, such as a laser or microwave signal, was used, the system became more chaotic – ultimately demonstrating the phenomenon known as the name of hyperchaos.

When the qubits were energized by the power source, they changed state, like normal computer bits moving between zero and one, but in a much more irregular and unpredictable way. However, the researchers found that the degree of complexity (hyperchaos) did not increase exponentially as the size of the system increased – as one would expect – but on the contrary, it remained proportional to the number of units.

In a new article, “Emergence and control of complex behaviors in driven systems of qubits interacting with dissipation”, published in the journal Nature Quantum information NPj, the team shows that this phenomenon has great potential to allow scientists to simulate large quantum systems.

One of the corresponding authors, Dr Alexander Zagoskin, Loughborough School of Science, said: “A good analogy is in aircraft design. In order to design an airplane, it is necessary to solve some hydro equations (aero) dynamics, which are very difficult to solve and only became possible after WWII, when powerful computers appeared. Nevertheless, people had designed and flown airplanes long before that. It was because that the behavior of air flow could be characterized by a limited number of parameters, such as Reynolds number and Mach number, which could be determined from experiments on small-scale models. Direct simulation of a quantum system in all details, using a classical computer, becomes impossible once it contains more than a few thousand qubits. Essentially, there is not enough matter in it. ‘Universe for constr Use a conventional computer capable of handling the problem. If we can characterize different regimes of a quantum computer of 10,000 qubits in 10,000 of these parameters instead of 2^10,000 – which is about 2 times 1 with three thousand zeros – that would be a real breakthrough. ”

The new results show that a quantum system presents qualitatively different models of general behavior of cases, and the transitions between them are governed by a relatively small number of parameters.

If this is generally the case, researchers will be able to determine the critical values ​​of these parameters from, for example, the construction and testing of scale models, and, by taking some measurements of the real system, to tell whether the parameters of our quantum processor let it work properly or not.

As a bonus, the controllable complexity of the behavior of large quantum systems opens up new possibilities in the development of new quantum cryptography tools.