In the previous post, we have looked at the basic ideas behind quantum error correction, namely the encoding of logical states so that we are able to detect and correct errors like bit flip and phase flip errors. Unfortunately, this is not yet good enough to implement quantum computing in a fault-tolerant way. What is … Continue reading Fault tolerant quantum computing

# Category: Quantum computing

# Basics of quantum error correction

Do usable universal quantum computers exist today? If you follow the recent press releases, you might believe that the answer is "yes", with IBM announcing a 50 qubit quantum computer and Google promoting its Bristlecone architecture with up to 72 qubits. Unfortunately, the world is more complicated than this - time to demystify the hype … Continue reading Basics of quantum error correction

# Using Python to access IBMs quantum computers

In a previous post, we have looked at IBMs Q experience and the graphical composer that you can use to build simple circuits and run them on the IBM hardware. Alternatively, the quantum hardware can be addressed using an API and a Python library called Qiskit which we investigate in this post. Installation and setup … Continue reading Using Python to access IBMs quantum computers

# Quantum simulation

In his famous lecture Simulating Physics with computers, Nobel laureate Richard Feynman argued that non-trivial quantum systems cannot efficiently be simulated on a classical computer, but on a quantum computer - a claim which is widely considered to be one of the cornerstones in the development of quantum computing. Time to ask whether a universal … Continue reading Quantum simulation

# Navigating downhill: the quantum variational eigensolver

In quantum mechanics, the dynamics of a system is determined by its Hamiltonian, which is a hermitian operator acting on the Hilbert space that describes the system at hand. The eigenstates and eigenvalues of the Hamiltonian then correspond to stationary states and their energies, and finding these eigenstates and the corresponding eigenvalues is the central … Continue reading Navigating downhill: the quantum variational eigensolver

# Into the quantum lab – first steps with IBMs Q experience

Even though physical implementations of quantum computers make considerable progress, it is not likely that you will have one of them under your desk in the next couple of years. Fortunately, some firms like IBM and Rigetti have decided to make some of their quantum devices available only so that you can play with them. … Continue reading Into the quantum lab – first steps with IBMs Q experience

# Shor’s quantum factoring algorithm

Until the nineties of the last century, quantum computing seemed to be an interesting theoretical possibility, but it was far from clear whether it could be useful to tackle computationally hard problems with high relevance for actual complications. This changed dramatically in 1994, when the mathematician P. Shor announced a quantum algorithm that could efficiently … Continue reading Shor’s quantum factoring algorithm