To do universal quantum computation, we need at least one two qubit entangling gate. All the gates we talk about in this article are equivalent to a Controlled NOT gate up-to single qubit rotations. Early proposals for doing gates included gates that depended on inter-atomic forces. These forces are weak and thus the gates were slow. The first fast gate was proposed by Jaksch et al. and made use of the principle of Rydberg Blockade (discussed below). Since then, most gates that have been proposed use this principle. We call all such gates Rydberg mediated gates and discuss them below.