Quantum state engineering with spins

Magnetic resonance methods and in particular Nuclear Magnetic Resonance in the liquid state were the first experimental techniques to implement quantum computing algorithms. The main drawbacks of these methods sofar have been the highly mixed nature of the quantum states and scalability issues. Recently, efforts have been made to address these problems by applying magnetic resonance to solid state systems at lower temperatures. In this contribution, we give an overview of our results on accurately controlling and measuring the quantum state of spin systems in the liquid and in particular in the solid state at low temperatures using Nuclear Magnetic Resonance and Electron Spin Resonance.