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

# Category: Quantum computing

# 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

# Quantum gates

So far, we have looked at states of a quantum computer and expressed these states in terms of qubits. However, just having a static state is of very limited use - to perform actual computations, we of course have to change our state over time. In quantum mechanics, state changes are described by unitary transformations … Continue reading Quantum gates

# Qubits and Hilbert spaces

When you use your favorite search engine to search for information on quantum computing, the first term that will most likely jump at you is the qubit. In this post, I will try to explain what this is and how it is related to the usual framework of quantum mechanics. Please be aware that this … Continue reading Qubits and Hilbert spaces

# Quantum computing

When I started this blog, my intention was to document my own attempts to learn and understand some of the topics at the intersection of computer science, physics and mathematics that have the potential to change the world in which we work and live. After spending some time with one of these topics - machine … Continue reading Quantum computing