Quantum computer, although it draws on other physical properties than classical computers do not make it possible to solve a new class of problems. Any problem not insoluble by a quantum computer can be solved by a classical computer. However, due to the specific properties of quantum computers could be some problems solved much faster, which in practice significantly poszerzyłoby range of problems for which computers can be used. A classic example is Shor's factoring algorithm, used to break down numbers into prime factors. Implementation of a similar algorithm for kilkudziesięciocyfrowych numbers in modern computers would exceed the average length of human life, and for even larger numbers - the life of the universe. On quantum computers would be possible to carry out these operations in a more realistic period.
The most common model of quantum computation the quantum state of the system is represented by a vector in Hilbert space skończeniewymiarowej (qubit). However, the operations carried out are described by unitary matrices.
