The quantum Fourier Transform

We are getting closer to the most spectacular early quantum algorithm - Shor's algorithm for factoring large composite numbers which can be used to break the most widely used public key cryptography systems. But before we can tackle this algorithm, there is one more thing that we need to understand - the quantum Fourier transform. … Continue reading The quantum Fourier Transform

Grover’s algorithm – unstructured search with a quantum computer

In the last post, we have looked at the Deutsch-Jozsa algorithm that is considered to be the first example of a quantum algorithm that is structurally more efficient than any classical algorithm can probably be. However, the problem solved by the algorithm is rather special. This does, of course, raise the question whether a similar … Continue reading Grover’s algorithm – unstructured search with a quantum computer

Quantum algorithms – a first example

We have now seen how quantum gates implement unitary transformations on qubits. Intuitively, we should, as in the classical case, now be able to combine these quantum gates into quantum algorithms that perform more complex sequences of manipulations of a quantum state. In this post, we will look at a first example to get an … Continue reading Quantum algorithms – a first example