Mar 06, 2019 08:00:00

Google engineers comment on the question 'What is a quantum computer?'

Quantum computers are expected to be put to practical use in applications such as artificial intelligence and development of new drugs, but for most people who do not have expertise in quantum mechanics, 'very high-performance versions of desktop PCs that are familiar' Such recognition may be the best. However, in reality, it seems that it is not correct to regard quantum computers as super-high-performance computers, and then engineers at quantum computer development at Google explain the question of what it looks like.

Ask a Techspert: What is quantum computing?
https://www.blog.google/inside-google/googlers/ask-techspert-what-quantum-computing/

◆ The difference between quantum computer and general computer
Although 'information' is an abstract concept in a sense, physical phenomena occur in computers that process information. The computer treats the information as a series of 'bits', and each bit takes either a '0' or a '1' value. The '0' and '1' are controlled by a small on / off switch inside the computer. In other words, emails, photos, and YouTube movies are all made on and off in sequence. In a word, a quantum computer can be said to be a computer that processes information with “ Qubits ” instead of this “bit”.

So how are 'bits' and 'qubits' totally different? Bits are either '0' or '1', but qubits have more possibilities. For example, the '0' in the qubit is like the North Pole and the '1' is like the South Pole, and the qubit can exist anywhere on the earth besides the North Pole and the South Pole. If a qubit is on the equator, that qubit is expressed as '50% chance of '0' and 50% of '1''. When a quantum computer handles qubits, it is necessary to repeatedly measure whether the qubit is actually '0' or '1'.

◆ The figure of quantum computer
In Google's quantum computer, the qubits are in a

resonant circuit made of aluminum arranged on a silicon chip. This circuit is controlled in an environment close to absolute zero, less than 50 milliKelvins , because it must be kept superconducting to avoid electrical losses. The whole quantum computer is larger than humans, but most are cooling equipment, and the quantum processor itself is only about the size of a coin.

◆ Application of quantum computer
Quantum computers are fundamentally different from ordinary computers in the way they process information, so they can do calculations that are not possible with ordinary computers. On the other hand, quantum computers have very different uses and specific strengths from general computers, so that we use cars to go to a nearby supermarket, but we do not ride on planes or spacecraft. Has specialized performance in the field. In other words, quantum computers are not just high-performance versions of general purpose computers. An example of quantum computer's specialty is the simulation of chemical reactions.

Even if the molecular structure of a substance is known, what properties it has in the real world can not be determined until the molecule is actually synthesized and tested. Unlike building blocks, atoms have an infinite number of bonding patterns, and even adding one atom doubles the parameters, so it is impossible for ordinary computers to simulate the behavior of small molecules. On the other hand, quantum computers perform calculations based on the same principle as the physics of the ultra-microscopic world that governs the behavior of molecules, so they are good at simulating the behavior of molecules. For this reason, we can expect activity in the field of materials research, such as development of better fertilizers, anti-corrosion coatings, and more efficient solar cells.

Also, there is a movie that explains Gistina working at Google's Quantum Artificial Intelligence Laboratory in an easy-to-understand way about quantum computers, and you can see the commentary by Gistina with Japanese subtitles from the following.

What is a quantum computer? (QuantumCasts)-YouTube