**quantum computer**

*abbr.,*QK (rus. квантовый компьютер

*otherwise*квантовое вычислительное устройство

*abbr.,*КК) — computing device that processes data using quantum mechanical effects, such as superposition (being in multiple states simultaneously with a certain probability) and entanglement of quantum states (interconnected wave functions).

### Description

The quantum properties of microobjects can be used to represent and process data; that is the key principle underlying operation of a quantum computer. Unlike the classical computer, whose memory is a set of bits (basic units of information that can be stored in a physical system, and take one of the two different states designated as 0 and 1), the quantum computer has a memory consisting of a set of so-called qubits (quantum bits). Each qubit can be not only in the states 0 or 1, but in any state, which is a quantum superposition of the states 0 and 1; moreover, a pair of qubits forming a quantum system can be in any state, which is a superposition of four states, etc. (in general, a quantum system of

In simple terms, the process of calculating in a quantum computer is a sequence of manipulations of the system of qubits through basic quantum operations; the state of a quantum system measured at the end is the result of a computer operation.

Today, despite the absence of significant achievements in the field of QC (experimentally quantum computing was performed only for systems with a very small number of qubits), theoretical and practical research in this direction continues.

The main problems associated with QC creation are, firstly, the need for very high precision measurements of quantum states, and secondly, the need to isolate the qubit systems from external influences that can destroy the quantum systems, or introduce significant errors.

*n*qubits can be in one of 2^{n}states).In simple terms, the process of calculating in a quantum computer is a sequence of manipulations of the system of qubits through basic quantum operations; the state of a quantum system measured at the end is the result of a computer operation.

Today, despite the absence of significant achievements in the field of QC (experimentally quantum computing was performed only for systems with a very small number of qubits), theoretical and practical research in this direction continues.

The main problems associated with QC creation are, firstly, the need for very high precision measurements of quantum states, and secondly, the need to isolate the qubit systems from external influences that can destroy the quantum systems, or introduce significant errors.

#### Author

- Razumovsky Alexey S.

#### Sources

- Quantum computer // Wikipedia, the free encyclopedia. — http://en.wikipedia.org/wiki/Quantum_computer (referencedate: 12.12.2011).
- Fejjgel'man M. The ideological foundation // Computerra, 1997–2009. — http://offline.computerra.ru/offline/2001/414/12932/index.html (reference date: 26.07.2010).
- Omel'janchuk A.N., Obolenskijj M. A. Quantum computers and Josephson qubits // Universitety: nauka i prosveshhenie. — Khar'kov: Imperial, 2005. №2(22). p. 10–17.