[8] He studied with Yakir Aharonov, followed by postdoctoral research positions with François Englert, and then with Abner Shimony[9] and Bahaa Saleh.

He also proved that there is a unique measure of entanglement for pure bi-partite quantum states[17] (the von Neumann entropy of the reduced density matrix).

With Daniel Rohrlich, Popescu showed that nonlocal correlations stronger than those allowed by quantum mechanics could exist without violating Einstein's principle of no superluminal signalling.

[20] Crucially, this is the first demonstration of equilibration – the most important aspect of statistical mechanics – directly from first principles, without any additional assumptions.

The result holds even in situations in which the standard assumptions of statistical mechanics do not apply, such as systems with strong long-range, non-screened interactions where temperature cannot even be defined.