Ars Technica reports: "Since the modern communications revolution got into full swing with the advent of the telegraph, people have always wondered just how much information can be sent down that line. In classical communication, this is governed by Shannon's law, which looks at the correlation between input and output signals. Once the noise in the channel reaches a particular level, the output and the input are no longer correlated and you have to slow the bit rate down. If the noise is high enough, there is a point where no communication is possible. Recently, researchers have been asking the same question about quantum communications channels and it turns out that the answer isn't really that clear."