Quantum computer overtook supercomputer in calculation of physical task

Scientists from IBM Quantum in New York, in collaboration with researchers from the University of California at Berkeley and the National Laboratory of Lawrence in Berkeley, have published a research paper in the journal Nature that reveals how a quantum computer can provide more accurate results for specific types of calculations than a modern “classic” supercomputer.

The researchers compared the IBM Eagle quantum computer, which comprises of 127 cubes, to the Summit supercomputer, one of the most powerful in the world. To carry out the comparison, the researchers tackled a problem from the field of quantum mechanics concerning determining the energy of the main state of the particle system. This task often arises when studying the quantum properties of superconductors and new electronic materials.

To solve the problem, the quantum computer used an algorithm called QAOA (Quantum Approximate Optimization Algorithm), while the supercomputer used a classic algorithm called QMC (Quantum Monte Carlo), which imitates a quantum system using random numbers.

Results from the study revealed that as the complexity of the problem increased, the quantum computer continued to provide correct answers, while the supercomputer began to make errors. These findings indicate that quantum computers may have an advantage over traditional calculations for specific types of calculations, although they are subject to noise and errors.

The researchers also applied an error elimination method called Error Mitigation, which reduces the impact of noise on the results of a quantum computer. This method significantly boosted the accuracy of the quantum algorithm and made it more competitive when compared to traditional algorithms.

“We are included in the mode where a quantum computer can do things that current algorithms on classic computers cannot do,” said Sajant Anand, a graduate student of the University of California in Berkeley.

Sarah Sheldon, senior quantum theory manager and capabilities in IBM Quantum, added: “We can begin to think about quantum computers as a tool for studying problems that we could not study otherwise”.

In summary, the study has shown that quantum computers can provide a superior solution for specific types of calculations, and the Error Mitigation method can reduce noise and improve accuracy.

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