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I have the following quadratic cost function

$$ J(t) = \int_{0}^{t} \left[ z(\tau)^\ast A z(\tau) + w(\tau)^\ast B w(\tau) \right] d(\tau) $$

where $w = -Rz$ and A and B are matrices whose values are known. Moreover, $z$ is a vector containing my continous variables. I want to find $R$ which optimizes the cost function and this $R$ is a matrix of real values.

I have read about several ways on how quantum algorithms can be used for optimization of QUBO by using an adiabatic process where a hamiltonian time evolves into another hamiltonian whose ground state is designed to be the minimum of the cost function.

I have since searched for ways in which my problem can be formalized into a QUBO problem and I have found as mentioned in this paper and in answers to questions along the line of this and this one, that continuous variables need to be binarized to fit in the QUBO description. This ultimately leads to an increase of number of binary variables.

My Question resides in that I do not understand how I can map the output of my QAOA to be the values of the $R$ matrix. To clarify what I mean more accurately, consider the maxcut problem. In the maxcut problem you can think of the output of measurement of each qubit as which node is 1 and which is 0. In case of continuous variable optimization, it is the mapping of the output to the $R$ matrix that is missing from my understanding conceptually and mathematically. Please feel free to correct any incorrect assumptions in my understanding along the way.

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  • $\begingroup$ When writing integrals the time dependent variables need be clearly stated. As of now, the integrand looks constant. $\endgroup$
    – MonteNero
    Commented Aug 22 at 19:43
  • $\begingroup$ Okay I have updated the integral $\endgroup$ Commented Aug 22 at 19:58
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    $\begingroup$ Unfortunately the problem at hand is not suitable for QAOA or quantum annealing or quantum computing in general. Discritizing variables will just make the problem worse and entirely neglect all potential quantum benefits. Besides your variables are time dependent. The best bet is to use classical continious optimization theory. If you still want to go QC route then this will be pretty misguided use of QC. $\endgroup$
    – MonteNero
    Commented Aug 22 at 22:45
  • $\begingroup$ Can you please clarify why does time dependency, affect the possibility of being able to solve the problem effectively? $\endgroup$ Commented Aug 24 at 16:21

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