Theoretical physicists completely determine the statistics of quantum entanglement

Amazing stuff!

"For the first time, theoretical physicists ... have completely determined the statistics that can be generated by a system using quantum entanglement. This achievement paves the way for exhaustive test procedures for quantum devices. ..."

"... An entangled system comprises two parts that are inextricably linked. When these subsystems are measured, this link appears in the frequencies of the observed results. A signature of the quantum regime par excellence, these statistics are a foundation of the growing field of quantum information. Until now, however, statistics derived from measurements on entangled states have always resisted analysis. By identifying all the frequencies needed to reconstruct the description of the measured quantum system, this work presents the first complete and explicit description of a set of quantum statistics.

This result has both fundamental and applied significance. Indeed, the type of reconstruction obtained forms the basis of the most advanced validation methods for quantum devices. This work paves the way for new, more comprehensive test procedures for quantum devices. At the same time, by determining the extent of quantum statistics, this result identifies the limits of quantum physics itself. It thus informs us about the scope of quantum theory and offers new perspectives for better understanding it."

From the abstract:

"In any experimental setting, quantum physics provides the statistical distributions that the observed outcomes are expected to follow. The set formed by all these distributions contains the imprint of quantum theory and captures some of its core properties. So far, only partial explicit descriptions of this set have been found for Bell-type settings in which entangled states can be shared and measured by independent observers.

Here we obtain the complete explicit and analytical description of a full set of quantum statistics in terms of its extremal points. This is made possible by finding all bipartite quantum states and pairs of binary measurements that can be self-tested, that is, reconstructed from empirical statistics only. Our description precisely reveals some of the extent and limitations of quantum theory."

Theoretical physicists completely determine the statistics of quantum entanglement

Quantum Statistics (original news release) "In a new paper ... provide an answer to a 40-year-old open question about the scope of quantum entanglement."

Quantum statistics in the minimal Bell scenario (no public access)