> Weak measurements do destroy some entanglement, just not "all" of it. Which measure of degree of entanglement best characterizes state linkage across spaceti

> Weak measurements do destroy some entanglement, just not "all" of it. Which measure of degree of entanglement best characterizes state linkage across spacetime? Depending on definition, doesn't a laser pointer entangle phase states across spacetime, but only slower than c (the speed of transverse photonic waves in a total vacuum)? Are the states synchronized with a constant delay? Quantum discord: https://en.wikipedia.org/wiki/Quantum_discord https://en.wikipedia.org/wiki/Quantum_discord : > In quantum information theory, quantum discord is a measure of nonclassical correlations between two subsystems of a quantum system. It includes correlations that are due to quantum physical effects but do not necessarily involve quantum entanglement. Quantum mutual information: https://en.wikipedia.org/wiki/Quantum_mutual_information https://en.wikipedia.org/wiki/Quantum_mutual_information