Experimentally bounding deviations from quantum theory for a photonic three-level system using theory-agnostic tomography

Understand

If one seeks to test quantum theory against many alternatives in a landscape of possible physical theories, then it is crucial to be able to analyze experimental data in a theory-agnostic way.

• This can be achieved using the framework of Generalized Probabilistic Theories (GPTs).
• Here, we implement GPT tomography on a three-level system corresponding to a single photon shared among three modes.
• This scheme achieves a GPT characterization of each of the preparations and measurements implemented in the experiment without requiring any prior characterization of either.