# Basics

QuBit, quantum teleportation and entanglement. These concepts are essential for understanding quantum technologies such as the quantum computer or quantum networks. Using graphics and small examples the three terms are discussed in more detail in the following.

*Excursus:* Why quantum computing? Grover’s algorithm.

To find an element in an unsorted database with N elements, classical algorithms need a computing time that is proportional to O(N) (Big O notation). Already in 1996 L. Grover showed that a quantum algorithm could reduce the number of computational steps to an order of O(N^{0.5}).

Grover’s algorithm may therefore strongly accelerate the lookup of elements in a database compared to classical computers by reducing the required number of computational steps. More information about Grover’s algorithm: https://github.com/Qiskit/textbook/blob/main/notebooks/ch-algorithms/grover.ipynb

Another famous quantum algorithm is Shor’s algorithm which could strongly accelerate the factoring of numbers.

Version: 17.06.2024