When is a deck 'truly shuffled'?

We all shuffle cards, but when is a deck truly shuffled? Firstly, what does ‘truly shuffled’ mean? Secondly, are some shuffles just better than others? We’ll explore mixing times, coupling (a technique for analysing markov chains), and why some shuffles are superior than others. Disclaimer: The content presented is not original research, but rather an attempt to explain already known concepts in a…