A quantum computer is a computing device that uses the phenomena of quantum mechanics to transmit and process data. The idea of quantum computing was independently proposed by Yuri Manin and Richard Feynman in the early 80s of the last century. Since then, a tremendous amount of work has been done to create a quantum computer. However, a full-fledged universal quantum computer is still a hypothetical device, the development of which is associated with the serious development of quantum theory. To date, a few experimental systems have been created with an algorithm of low complexity. How does a quantum computer work - more on that in today's issue!
The main difference between a quantum computer and a classical one is the presentation of information. Conventional computers based on transistors and silicon chips use a binary code to process information. A bit, as you know, has two basic states - zero and one, and can only be in one of them. As for a quantum computer, its work is based on the principle of superposition, and instead of bits, quantum bits are used, called qubits. A qubit also has two basic states: zero and one. However, thanks to the superposition, a qubit can take on the values obtained by combining them, and be in all these states simultaneously. This is the parallelism of quantum computing, that is, there is no need to iterate over all possible variants of the states of the system. Besides,to describe the exact state of a system, a quantum computer does not need huge computing power and volumes of RAM, since only 100 qubits are enough to calculate a system of 100 particles, and not a trillion trillion bits.
It is also worth noting that a change in the state of a certain qubit in a quantum computer leads to a change in the state of other particles, which is another difference from a conventional computer. And this change can be managed. The process of a quantum computer was proposed by British theoretical physicist David Deutsch in 1995, when he created a chain capable of performing any calculations at the quantum level. According to his scheme, first a set of qubits is taken and their initial parameters are recorded. Then the necessary transformations are performed using logical operations and the resulting value is written, which is the result of the computer. Qubits act as wires, and logical blocks perform transformations.
According to scientists, quantum computers will be millions of times more powerful than current ones. A wide variety of algorithms for the operation of a quantum computer have already been described, and even special programming languages are being developed. Researchers at Cisco Systems predict that a fully functional quantum computer will appear by the middle of the next decade. Japan is the leader in this area: more than 70% of all research is done in this country.