5.1 From adiabatic computing to QAOA
In this first section, we will introduce all the theoretical concepts that will allow us to understand QAOA in depth. But before that, we will give an intuitive idea of how QAOA works by studying its relationship with quantum annealing. Sounds interesting? Then keep on reading, because here we go!
5.1.1 Discretizing adiabatic quantum computing
In the previous chapter, we studied adiabatic quantum computing and its practical realization, quantum annealing, and we learned how to use them in order to obtain approximate solutions to combinatorial optimization problems. Both of these techniques relied on the adiabatic theorem. When we applied them, we used a time-dependent Hamiltonian that induced a continuous transformation of the state of a quantum system: from an initial state to a final state that — hopefully — has a big overlap with the solution to our problem.
A natural question to ask is whether there is any sort of analog to this...