Embedding returns energies which are lower than the true minimum energy
In my problem, I coupled many qubits together to form a chain. However, after running QUBO and negleting broken chain, I still got some energies which are lower than the true minimum energy. Why it would be the case?
As far as I know, if 2 qubits are coupled to form a chain, a penalty function will be added, so if the chain is broken, energies will get higher than the true minimum energy.
But how about the case of coupling many qubits to form a chain?