Efficient and versatile tomography of bosonic quantum states (Part II)*

Quantum reservoir processing (QRP) is an alternative approach to conventional Wigner tomography for bosonic superconducting circuits. The estimation of an arbitrary state of dimension D only requires D^2-1 measurements of the photon number distribution, which are then inverted with a linear map to reconstruct the density matrix.

Here we present the experimental data where we show that, for the same number of measurements, QRP reconstructs states with higher fidelity than Wigner tomography. We also show how QRP fidelity scales more favorably both under coherent and incoherent errors.

This project may contribute a new tool, particularly useful in the presence of incoherent errors, for efficient state estimation and reconstruction for quantum information processing with bosonic modes.