## Definition Edit

A **quantum computer** is a device for computation that makes direct use of quantum mechanical phenomena, such as superposition and entanglement, to perform operations on data.

## Overview Edit

The basic principle behind quantum computation is that quantum properties can be used to represent data and perform operations on these data. A theoretical model is the quantum Turing machine, also known as the universal quantum computer.

“ | [t]he basic principle of quantum computation is that the quantum properties can be used to represent and structure data, and that quantum mechanisms can be devised and built to perform operations with this data.^{[1]}
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Although quantum computing is still in its infancy, experiments have been carried out in which quantum computational operations were executed on a very small number of qubits (quantum bit) that can occupy multiple states simultaneously. Both practical and theoretical research continues with interest, and many national government and military funding agencies support quantum computing research to develop quantum computers for both civilian and national security purposes, such as cryptanalysis.

“ | Quantum computers are available with dozens of the fundamental components known as physical qubits, although a general use quantum computer may need more than 100,000 physical qubits. To develop quantum computers that can solve problems of practical significance — such as factoring the large numbers used in encryption schemes — it will be necessary to improve their hardware; such efforts could take 20 years. For example, chips would need to hold more physical qubits while maintaining accuracy and precision.^{[2]}
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"Quantum computers may one day be able to quickly complete tasks that classical computers cannot carry out efficiently — such as factoring large numbers, a task central to cracking current cryptographic systems."^{[3]}

It has the potential to become a major disruptive technology affecting cryptography and cryptanalysis given the potential increase in computing speed and power over conventional transistor-based computing.

## References Edit

- ↑ SMART 2020: Enabling the Low Carbon Economy in the Information Age, Glossary, Appendix 6/84.
- ↑ Science & Tech Spotlight: Quantum Technologies.
- ↑
*Id.*

## See also Edit

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