Disclaimer: machine translated by DeepL which may contain errors.
What If Quantum Computers Became Reality?
Hayata Yamasaki (Graduate School of Information Science and Technology / Associate Professor, Department of Information Science and Technology)
What would you like to do if we had a quantum computer? When I asked this question, the five researchers on stage looked at each other. We invited five leading researchers in the field from around the world, and about 100 participants gathered at the venue. In addition to lectures introducing the theoretical and experimental frontiers of quantum computer development, there was a panel discussion in which researchers from different fields of expertise engaged in lively debate.
What exactly is a quantum computer? It is a computer that uses the principles of quantum mechanics governing the microscopic world of atoms and light to enable new information processing. Computers that we use in our daily lives perform calculations using "bits" (0 or 1) as their unit of measurement. Quantum computers, on the other hand, use a unit called a "qubit. A qubit can have a "superposition" of 0s and 1s. By taking advantage of this property, it is expected to be possible to solve calculations that were not practical with conventional computers, such as the prime factorization of huge integers and simulations of complex quantum phenomena, in a realistic amount of time. In addition, more secure cryptography can be realized through quantum communication. However, not all problems can be solved in a massively parallel fashion in an instant. The strength of quantum computers is demonstrated only when there is a special mathematical structure behind the computation. In the case of prime factorization, for example, quantum algorithms can dramatically speed up the process by detecting the hidden periodicity in the numbers. On the other hand, it should not be misunderstood that not every problem can be made faster by a quantum computer.
There are still many challenges in realizing a quantum computer. Qubits are very sensitive to noise, and information is easily lost during computation. Building a scalable quantum computer that can control a large number of qubits with high precision is a big challenge for researchers around the world. Current methods such as noisy medium-scale devices (NISQ devices) and quantum annealing cannot suppress the effect of noise, making it difficult to achieve practical speedups that exceed those of state-of-the-art classical algorithms. Therefore, methods to overcome noise by quantum error correction are being actively studied, and development toward a noise-resistant quantum computer is progressing rapidly. On the theoretical side, more efficient quantum error correction and promising applications of quantum information processing are also being explored.
As the workshop panel discussion drew to a close, the moderator asked the audience, "Does anyone have any questions? The moderator asked the audience, "Any questions? At such occasions, people tend to be reserved until the first person comes forward. However, if someone asks a question, the atmosphere at once relaxes, and after that, it becomes easier for hands to come up one after another. As the organizer, it is my role to encourage the first step. So I raised my hand and asked the researchers again, "If a quantum computer is really realized, what would you like to do?" I asked the researchers again. After a short pause, each researcher began to talk about his or her dream.
After the workshop, I went to Genghis Khan with my co-researchers who had organized the workshop. What do you want to do with a quantum computer? I was asked. Human beings have made the edge of the universe visible through telescopes and unknown moving objects (microorganisms later named amoebas and paramecia) in lake water visible through microscopes for the first time. Each of these is a new tool that has made visible a world that was previously unimaginable. I believe that the quantum computer is also a tool that enables us to "compute" what "could not be computed before" and shows us a new world. Even if we do not look into the end of the universe, there is a possibility that we can look into the microscopic world right in front of us, a world that we have not yet seen. What will we "see" with this new tool?
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