Characterization of high-dimensional entangled systems via mutually unbiased measurements

Understand

Mutually unbiased bases (MUBs) play a key role in many protocols in quantum science, such as quantum key distribution.

• However, defining MUBs for arbitrary high-dimensional systems is theoretically difficult, and measurements in such bases can be hard to implement.
• We show experimentally that efficient quantum state reconstruction of a high-dimensional multi-partite quantum system can be performed by considering only the MUBs of the individual parts.
• The state spaces of the individual subsystems are always smaller than the state space of the composite system.