If we violate a Bell inequality, we know we have quantum entanglement, and it used to be thought that these two notions were one and the same. At least, this was commonly accepted until 1989, when R.F. Werner actually proved that this isn’t so. There really are some entangled states that are Bell-local — states…
It’s a principle as old as science itself, and remarkably, remains essentially unchanged in the light of revolution after revolution in our understanding of physics. Many of us see it in our first year of physics and never again, as calculus-based treatments of fluid dynamics are usually left for those seeking to specialize in a…
Though any pair of particles, given their history, might happen to be entangled, some pairs are more entangled than others. Since at least the 1990s, physicists have been honing their understanding and treatment of quantum entanglement. In the past few decades, entanglement has been used as a resource in groundbreaking new techniques giving rise to…