Self-Guided Quantum Tomography in High-Dimensional Systems

Quantum tomography-characterising a quantum system by assigning it a quantum state-is an essential building block for future technologies like quantum metrology or quantum computation. Ideal quantum tomography is accurate and robust to noise while being quick and efficient. The standard technique for decades, full quantum tomography (FQT), only fulfils parts of these criteria and quickly becomes unfeasible, even for medium-sized systems. As the number of possible states increases, the amount of measurements to characterise the system grows exponentially. The very feature that gives quantum physics immense possibilities hinders our ability to describe it. Additionally, FQT is neither robust to noise nor experimental errors and generally fails in the presence of these environmental perturbations unless additional resources are used.