In the QAOA algorithm for MaxCut, the authors construct a very specific scheme where the qubits (corresponding to the vertices of the graph) are transformed using a sequence of unitaries
$$|\gamma, \boldsymbol{\beta}\rangle= U\left(B, \beta_{p}\right) U\left(C, \gamma_{p}\right) \cdots U\left(B, \beta_{1}\right) U\left(C, \gamma_{1}\right)|s\rangle$$
Here $\vert s\rangle$ is an intial state constructed by a Hadamard on the all zero state. The $U(B, \beta_i)$ and $U(C,\gamma_i)$ are also specific unitaries that the authors construct. The alternating sequence of $U(B, \beta_i)$ and $U(C,\gamma_i)$ is also specified.
QAOA works by iteratively measuring the output state $|\gamma, \boldsymbol{\beta}\rangle$. It uses a classical optimizer to choose the next set of angles $\{\beta_i\}$ and $\{\gamma_i\}$. This is repeated until the classical optimizer converges and the final measurement on the state $|\gamma, \boldsymbol{\beta}\rangle$ gives us the information of how to cut the graph.
Is there a reference that explains why this specific construction was chosen? The original paper introduces this construction and says that this yields a good cut but what motivated this very specific construction? Any references or links to talks would be greatly appreciated!
