Macroscopic features of quantum fluctuations in large- N qubit systems
A. B. Klimov, Carlos A Muñoz · Physical Review A · 2014
We introduce a discrete $Q$ function of an $N$-qubit system projected into the space of symmetric measurements as a tool for analyzing general properties of quantum systems in the macroscopic limit. For known states the projected $Q$ function helps to visualize the results of collective measurements, and for unknown states it can be approximately reconstructed by measuring the lowest moments of the collective variables.