Entangled photon-pairs are a vital resource in quantum information protocols ranging from quantum key distribution to teleportation. The commonly used technique for generating photon-pairs is by a three-wave mixing process called spontaneous parametric down-conversion (SPDC) in bulk crystals. The increased demand of quality entangled photon-pair sources for various applications and the readily available technology to...

Superconducting circuits are a prime contender both for realizing fault-tolerant quantum processors and for executing noisy intermediate-scale quantum (NISQ) algorithms. After a brief introduction to the quantum physics of superconducting circuits I will focus on the latter. The quantum approximate optimization algorithm (QAOA) is one of a whole class of variational methods, which are believed...