## Anyone can understand quantum mechanics - Part 3

Before we begin, HAVE YOU WATCHED THE VIDEO “ANYONE CAN QUANTUM”??? Paul Rudd, Keanu Reeves, Stephen Hawking, Quantum Chess, Quantum Physics for Babies, and even tardigrades: this video has it all!

## How to enhance separability and entanglement of quantum states

A quantum state \(\rho\) that is shared between two parties is called *separable* if it can be written as a convex combination of local quantum states \(\{\sigma_i\}\) and \(\{\tau_i\}\):

\[\rho = \sum_i p_i \sigma_i \otimes \tau_i.\]

States that are not separable are called entangled, and the distinction between these two types of states is important because there are many senses in which entangled states are exactly the "useful" ones in quantum information theory.