Physicists have discovered a potentially game-changing feature of quantum bit behavior that enables scientists to simulate complex quantum systems without the need for enormous computing power.
For some time, the development of next-generation quantum computers has been limited by the processing speed of conventional CPUs.
Even the fastest supercomputers in the world have not yet been powerful enough, and existing quantum computers are still too small to model moderate-sized quantum structures, such as quantum processors.
However, a team of researchers from the universities of Loughborough and Nottingham and Innopolis have now found a way to circumvent the need for such large amounts of power by employing the chaotic behavior of qubits – the smallest unit of digital information.
In modeling the behavior of quantum bits (kwbits), they found that when an external energy source, such as a laser or microwave signal, was used, the system became more chaotic, eventually becoming the phenomenon known as hyperchaos.
When the power supply was excited about the power supply, they switched from status, like ordinary computer bits moving between 0 and 1, 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 grew – this is what one would expect – but it remained proportional to the number of units.
In a new article, The emergence and control of complex behaviors in driven systems of interaction with quips with dissipation, published in the journal Nature NPJ quantum information, the team shows how this phenomenon has great potential to allow scientists to simulate large quantum systems.
One of the corresponding authors, dr. Alexandre Zagoskin, from Loughborough’s School of Science, said: ‘A good analogy is aircraft design.
‘To design an airplane, it is necessary to solve certain equations of hydro (aero) dynamics, which are very difficult to solve, and this was only possible after the Second World War when powerful computers appeared.
‘Nevertheless, people have designed and flown airplanes long before.
‘This was because the behavior of the airflow could be characterized by a limited number of parameters, such as the Reynolds number and the Mach number, which could be determined from small-scale model experiments.
“Without it, direct simulation of a quantum system in detail, with the help of a classical computer, becomes impossible once it contains more than a few thousand qubits.
‘Essentially, there is not enough matter in the universe to build a classical computer that can handle the problem.
“If we could characterize different regimes of a 10,000-kwab quantum computer by just 10,000 such parameters instead of 2 ^ (10000) – that’s about 2 times a 1 with three thousand zeros – it would be a real breakthrough. “
The new results show that a quantum system shows qualitatively different patterns of general business behavior, and the transitions between them are controlled by a relatively small number of parameters.
If applicable, the researchers can determine the critical values of these parameters, for example to build and test scale models, and by taking some measurements of the actual system, to determine whether the parameters of our quantum processor allow it to be correct. work or not.
As a bonus, the controllable complexity in the behavior of large quantum systems offers new possibilities in the development of new quantum cryptography tools.
Dr. Weibin Li, of the School of Physics and Astronomy, Nottingham University, said: ‘The results in this work are informative for the understanding of complex quantum dynamics.
Future quantum computers consist of thousands of quantum bits (qubits), which will be of greater order than the fastest classical computer on the market.
‘Here full control and characterization of quantum computers is the key to the execution of correct and massive computers.
In the quantum field, the number of degrees of freedom of a system grows exponentially with its size.
‘As full-scale quantum calculation is not yet available on a true quantum computer, the bottleneck is that only small-scale quantum computers, up to tens of qubits, can be simulated with classic supercomputers. ‘
Reference: “Emergence and control of complex behaviors in driven systems of interaction with quibits with dissipation” by AV Andreev, AG Balanov, TM Fromhold, MT Greenaway, AE Hramov, W. Li, VV Makarov and AM Zagoskin, 4 January 2021, NPJ quantum information.
DOI: 10.1038 / s41534-020-00339-1